1
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Jilani SB, Olson DG. Mechanism of furfural toxicity and metabolic strategies to engineer tolerance in microbial strains. Microb Cell Fact 2023; 22:221. [PMID: 37891678 PMCID: PMC10612203 DOI: 10.1186/s12934-023-02223-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Accepted: 10/05/2023] [Indexed: 10/29/2023] Open
Abstract
Lignocellulosic biomass represents a carbon neutral cheap and versatile source of carbon which can be converted to biofuels. A pretreatment step is frequently used to make the lignocellulosic carbon bioavailable for microbial metabolism. Dilute acid pretreatment at high temperature and pressure is commonly utilized to efficiently solubilize the pentose fraction by hydrolyzing the hemicellulose fibers and the process results in formation of furans-furfural and 5-hydroxymethyl furfural-and other inhibitors which are detrimental to metabolism. The presence of inhibitors in the medium reduce productivity of microbial biocatalysts and result in increased production costs. Furfural is the key furan inhibitor which acts synergistically along with other inhibitors present in the hydrolysate. In this review, the mode of furfural toxicity on microbial metabolism and metabolic strategies to increase tolerance is discussed. Shared cellular targets between furfural and acetic acid are compared followed by discussing further strategies to engineer tolerance. Finally, the possibility to use furfural as a model inhibitor of dilute acid pretreated lignocellulosic hydrolysate is discussed. The furfural tolerant strains will harbor an efficient lignocellulosic carbon to pyruvate conversion mechanism in presence of stressors in the medium. The pyruvate can be channeled to any metabolite of interest by appropriate modulation of downstream pathway of interest. The aim of this review is to emphasize the use of hydrolysate as a carbon source for bioproduction of biofuels and other compounds of industrial importance.
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Affiliation(s)
- S Bilal Jilani
- Thayer School of Engineering, Dartmouth College, 15 Thayer Drive, Hanover, NH, 03755, USA.
| | - Daniel G Olson
- Thayer School of Engineering, Dartmouth College, 15 Thayer Drive, Hanover, NH, 03755, USA
- Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA
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2
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Lee H, Jung Sohn Y, Jeon S, Yang H, Son J, Jin Kim Y, Jae Park S. Sugarcane wastes as microbial feedstocks: A review of the biorefinery framework from resource recovery to production of value-added products. BIORESOURCE TECHNOLOGY 2023; 376:128879. [PMID: 36921642 DOI: 10.1016/j.biortech.2023.128879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2023] [Revised: 03/07/2023] [Accepted: 03/09/2023] [Indexed: 06/18/2023]
Abstract
Sugarcane industry is a major agricultural sector capable of producing sugars with byproducts including straw, bagasse, and molasses. Sugarcane byproducts are no longer wastes since they can be converted into carbon-rich resources for biorefinery if pretreatment of these is well established. Considerable efforts have been devoted to effective pretreatment techniques for each sugarcane byproduct to supply feedstocks in microbial fermentation to produce value-added fuels, chemicals, and polymers. These value-added chains, which start with low-value industrial wastes and end with high-value products, can make sugarcane-based biorefinery a more viable option for the modern chemical industry. In this review, recent advances in sugarcane valorization techniques are presented, ranging from sugarcane processing, pretreatment, and microbial production of value-added products. Three lucrative products, ethanol, 2,3-butanediol, and polyhydroxyalkanoates, whose production from sugarcane wastes has been widely researched, are being explored. Future studies and development in sugarcane waste biorefinery are discussed to overcome the challenges remaining.
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Affiliation(s)
- Haeyoung Lee
- Department of Chemical Engineering and Materials Science, Graduate Program in System Health Science and Engineering, Ewha Womans University, Seoul 03760, Republic of Korea
| | - Yu Jung Sohn
- Department of Chemical Engineering and Materials Science, Graduate Program in System Health Science and Engineering, Ewha Womans University, Seoul 03760, Republic of Korea
| | - Subeen Jeon
- Department of Chemical Engineering and Materials Science, Graduate Program in System Health Science and Engineering, Ewha Womans University, Seoul 03760, Republic of Korea
| | - Hyoju Yang
- Department of Chemical Engineering and Materials Science, Graduate Program in System Health Science and Engineering, Ewha Womans University, Seoul 03760, Republic of Korea
| | - Jina Son
- Department of Chemical Engineering and Materials Science, Graduate Program in System Health Science and Engineering, Ewha Womans University, Seoul 03760, Republic of Korea
| | - Yu Jin Kim
- Department of Chemical Engineering and Materials Science, Graduate Program in System Health Science and Engineering, Ewha Womans University, Seoul 03760, Republic of Korea
| | - Si Jae Park
- Department of Chemical Engineering and Materials Science, Graduate Program in System Health Science and Engineering, Ewha Womans University, Seoul 03760, Republic of Korea.
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3
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Tong D, Zhan P, Zhang W, Zhou Y, Huang Y, Qing Y, Chen J. Surfactant‐Assisted Dilute Phosphoric Acid Plus Steam Explosion of Poplar for Fermentable Sugar Production. ChemistrySelect 2022. [DOI: 10.1002/slct.202200423] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Denghui Tong
- Ministry of Forestry Bioethanol Research Center Central South University of Forestry and Technology Changsha 410004 China
- Hunan Engineering Research Center for Woody Biomass Conversion Central South University of Forestry and Technology Changsha 410004 China
- Hunan International Joint Laboratory of Woody Biomass Conversion Central South University of Forestry and Technology Changsha 410004 China
- School of Materials Science and Engineering Central South University of Forestry and Technology Changsha 410004, China
| | - Peng Zhan
- Ministry of Forestry Bioethanol Research Center Central South University of Forestry and Technology Changsha 410004 China
- Hunan Engineering Research Center for Woody Biomass Conversion Central South University of Forestry and Technology Changsha 410004 China
- Hunan International Joint Laboratory of Woody Biomass Conversion Central South University of Forestry and Technology Changsha 410004 China
- School of Materials Science and Engineering Central South University of Forestry and Technology Changsha 410004, China
| | - Weifeng Zhang
- Ministry of Forestry Bioethanol Research Center Central South University of Forestry and Technology Changsha 410004 China
- Hunan Engineering Research Center for Woody Biomass Conversion Central South University of Forestry and Technology Changsha 410004 China
- Hunan International Joint Laboratory of Woody Biomass Conversion Central South University of Forestry and Technology Changsha 410004 China
- School of Materials Science and Engineering Central South University of Forestry and Technology Changsha 410004, China
| | - Yongcai Zhou
- Ministry of Forestry Bioethanol Research Center Central South University of Forestry and Technology Changsha 410004 China
- Hunan Engineering Research Center for Woody Biomass Conversion Central South University of Forestry and Technology Changsha 410004 China
- Hunan International Joint Laboratory of Woody Biomass Conversion Central South University of Forestry and Technology Changsha 410004 China
- School of Materials Science and Engineering Central South University of Forestry and Technology Changsha 410004, China
| | - Yilei Huang
- Ministry of Forestry Bioethanol Research Center Central South University of Forestry and Technology Changsha 410004 China
- Hunan Engineering Research Center for Woody Biomass Conversion Central South University of Forestry and Technology Changsha 410004 China
- Hunan International Joint Laboratory of Woody Biomass Conversion Central South University of Forestry and Technology Changsha 410004 China
- School of Materials Science and Engineering Central South University of Forestry and Technology Changsha 410004, China
| | - Yan Qing
- Ministry of Forestry Bioethanol Research Center Central South University of Forestry and Technology Changsha 410004 China
- Hunan Engineering Research Center for Woody Biomass Conversion Central South University of Forestry and Technology Changsha 410004 China
- Hunan International Joint Laboratory of Woody Biomass Conversion Central South University of Forestry and Technology Changsha 410004 China
- School of Materials Science and Engineering Central South University of Forestry and Technology Changsha 410004, China
| | - Jienan Chen
- Ministry of Forestry Bioethanol Research Center Central South University of Forestry and Technology Changsha 410004 China
- Hunan Engineering Research Center for Woody Biomass Conversion Central South University of Forestry and Technology Changsha 410004 China
- Hunan International Joint Laboratory of Woody Biomass Conversion Central South University of Forestry and Technology Changsha 410004 China
- School of Materials Science and Engineering Central South University of Forestry and Technology Changsha 410004, China
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4
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Jarboe LR, Khalid A, Ocasio ER, Fashkami KN. Extrapolation of design strategies for lignocellulosic biomass conversion to the challenge of plastic waste. J Ind Microbiol Biotechnol 2022; 49:6510821. [PMID: 35040946 PMCID: PMC9119000 DOI: 10.1093/jimb/kuac001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 01/18/2022] [Indexed: 11/12/2022]
Abstract
The goal of cost-effective production of fuels and chemicals from biomass has been a substantial driver of the development of the field of Metabolic Engineering. The resulting design principles and procedures provide a guide for the development of cost-effective methods for degradation, and possibly even valorization, of plastic wastes. Here we highlight these parallels, using the creative work of Lonnie O'Neal (Neal) Ingram in enabling production of fuels and chemicals from lignocellulosic biomass, with a focus on ethanol production as an exemplar process.
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Affiliation(s)
- Laura R Jarboe
- Department of Chemical and Biological Engineering, Iowa State University, Ames, IA 50011, USA
| | - Ammara Khalid
- Department of Chemical and Biological Engineering, Iowa State University, Ames, IA 50011, USA
| | - Efrain Rodriguez Ocasio
- Department of Chemical and Biological Engineering, Iowa State University, Ames, IA 50011, USA
| | - Kimia Noroozi Fashkami
- Department of Chemical and Biological Engineering, Iowa State University, Ames, IA 50011, USA
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5
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Shi A, Broach JR. Microbial adaptive evolution. J Ind Microbiol Biotechnol 2021; 49:6407523. [PMID: 34673973 PMCID: PMC9118994 DOI: 10.1093/jimb/kuab076] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2021] [Accepted: 09/27/2021] [Indexed: 01/08/2023]
Abstract
Bacterial species can adapt to significant changes in their environment by mutation followed by selection, a phenomenon known as “adaptive evolution.” With the development of bioinformatics and genetic engineering, research on adaptive evolution has progressed rapidly, as have applications of the process. In this review, we summarize various mechanisms of bacterial adaptive evolution, the technologies used for studying it, and successful applications of the method in research and industry. We particularly highlight the contributions of Dr. L. O. Ingram. Microbial adaptive evolution has significant impact on our society not only from its industrial applications, but also in the evolution, emergence, and control of various pathogens.
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Affiliation(s)
- Aiqin Shi
- Institute for Personalized Medicine, Department of Biochemistry and Molecular Biology, Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
| | - James R Broach
- Institute for Personalized Medicine, Department of Biochemistry and Molecular Biology, Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
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Ajala EO, Ighalo JO, Ajala MA, Adeniyi AG, Ayanshola AM. Sugarcane bagasse: a biomass sufficiently applied for improving global energy, environment and economic sustainability. BIORESOUR BIOPROCESS 2021; 8:87. [PMID: 38650274 PMCID: PMC10991612 DOI: 10.1186/s40643-021-00440-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Accepted: 08/28/2021] [Indexed: 11/10/2022] Open
Abstract
Sugarcane (Saccharum officinarum) bagasse (SCB) is a biomass of agricultural waste obtained from sugarcane processing that has been found in abundance globally. Due to its abundance in nature, researchers have been harnessing this biomass for numerous applications such as in energy and environmental sustainability. However, before it could be optimally utilised, it has to be pre-treated using available methods. Different pre-treatment methods were reviewed for SCB, both alkaline and alkali-acid process reveal efficient and successful approaches for obtaining higher glucose production from hydrolysis. Procedures for hydrolysis were evaluated, and results indicate that pre-treated SCB was susceptible to acid and enzymatic hydrolysis as > 80% glucose yield was obtained in both cases. The SCB could achieve a bio-ethanol (a biofuel) yield of > 0.2 g/g at optimal conditions and xylitol (a bio-product) yield at > 0.4 g/g in most cases. Thermochemical processing of SCB also gave excellent biofuel yields. The plethora of products obtained in this regard have been catalogued and elucidated extensively. As found in this study, the SCB could be used in diverse applications such as adsorbent, ion exchange resin, briquettes, ceramics, concrete, cement and polymer composites. Consequently, the SCB is a biomass with great potential to meet global energy demand and encourage environmental sustainability.
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Affiliation(s)
- E O Ajala
- Department of Chemical Engineering, University of Ilorin, Ilorin, Nigeria.
- Unilorin Sugar Research Institute, University of Ilorin, Ilorin, Nigeria.
| | - J O Ighalo
- Department of Chemical Engineering, University of Ilorin, Ilorin, Nigeria
- Department of Chemical Engineering, Nnamdi Azikiwe University, Awka, Nigeria
| | - M A Ajala
- Department of Chemical Engineering, University of Ilorin, Ilorin, Nigeria
| | - A G Adeniyi
- Department of Chemical Engineering, University of Ilorin, Ilorin, Nigeria
| | - A M Ayanshola
- Department of Water Resources and Environmental Engineering, University of Ilorin, Ilorin, Nigeria
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7
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Wang F, Shi D, Han J, Zhang G, Jiang X, Yang M, Wu Z, Fu C, Li Z, Xian M, Zhang H. Comparative Study on Pretreatment Processes for Different Utilization Purposes of Switchgrass. ACS OMEGA 2020; 5:21999-22007. [PMID: 32923758 PMCID: PMC7482092 DOI: 10.1021/acsomega.0c01047] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2020] [Accepted: 08/11/2020] [Indexed: 05/19/2023]
Abstract
Switchgrass (Panicum virgatum, L., Poaceae) with the advantages of high cellulose yield, and high growth even under low input and poor soil quality, has been identified as a promising candidate for production of low-cost biofuels, papermaking, and nanocellulose. In this study, 12 chemical pretreatments on a laboratory scale were compared for different utilization purposes of switchgrass. It was found that the pretreated switchgrass with sodium hydroxide showed considerable potential for providing mixed sugars for fermentation with 11.10% of residual lignin, 53.85% of residual cellulose, and 22.06% of residual hemicellulose. The pretreatment with 2.00% (v/v) nitric acid was the best method to remove 78.37% of hemicellulose and 39.82% of lignin under a low temperature (125 °C, 30 min), which can be used in the production of nanocellulose. Besides, a completely randomized design analysis of switchgrass pretreatments provided the alternative ethanol organosolv delignification of switchgrass for the papermaking industry with a high residual cellulose of 58.56%. Finally, scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FT-IR) were carried out to confirm the changes in functional groups, crystallinity, and thermal behavior of the three materials, respectively, from the optimal pretreatments.
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Affiliation(s)
- Fan Wang
- Key
Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and
Bioprocess Technology, Chinese Academy of
Sciences, 189 Songling Road, Qingdao, Shandong 266101, China
- Sino-Danish
College, University of Chinese Academy of
Sciences, 19(A) Yuquan
Road, Beijing 100049, China
| | - Dongxiang Shi
- Key
Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and
Bioprocess Technology, Chinese Academy of
Sciences, 189 Songling Road, Qingdao, Shandong 266101, China
- Lanzhou
University of Technology, 287 Langongping Road, Lanzhou, Gansu 730050, China
| | - Ju Han
- Key
Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and
Bioprocess Technology, Chinese Academy of
Sciences, 189 Songling Road, Qingdao, Shandong 266101, China
- Sino-Danish
College, University of Chinese Academy of
Sciences, 19(A) Yuquan
Road, Beijing 100049, China
| | - Ge Zhang
- Key
Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and
Bioprocess Technology, Chinese Academy of
Sciences, 189 Songling Road, Qingdao, Shandong 266101, China
- Sino-Danish
College, University of Chinese Academy of
Sciences, 19(A) Yuquan
Road, Beijing 100049, China
| | - Xinglin Jiang
- The
Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet Building 220, Kongens Lyngby 2800, Denmark
| | - Mingjun Yang
- Lanzhou
University of Technology, 287 Langongping Road, Lanzhou, Gansu 730050, China
| | - Zhenying Wu
- Key
Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and
Bioprocess Technology, Chinese Academy of
Sciences, 189 Songling Road, Qingdao, Shandong 266101, China
| | - Chunxiang Fu
- Key
Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and
Bioprocess Technology, Chinese Academy of
Sciences, 189 Songling Road, Qingdao, Shandong 266101, China
| | - Zhihao Li
- Key
Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and
Bioprocess Technology, Chinese Academy of
Sciences, 189 Songling Road, Qingdao, Shandong 266101, China
| | - Mo Xian
- Key
Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and
Bioprocess Technology, Chinese Academy of
Sciences, 189 Songling Road, Qingdao, Shandong 266101, China
- Sino-Danish
College, University of Chinese Academy of
Sciences, 19(A) Yuquan
Road, Beijing 100049, China
| | - Haibo Zhang
- Key
Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and
Bioprocess Technology, Chinese Academy of
Sciences, 189 Songling Road, Qingdao, Shandong 266101, China
- Sino-Danish
College, University of Chinese Academy of
Sciences, 19(A) Yuquan
Road, Beijing 100049, China
- . Phone: +86 139 6978 0438
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8
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Jilani SB, Dev C, Eqbal D, Jawed K, Prasad R, Yazdani SS. Deletion of pgi gene in E. coli increases tolerance to furfural and 5-hydroxymethyl furfural in media containing glucose-xylose mixture. Microb Cell Fact 2020; 19:153. [PMID: 32723338 PMCID: PMC7389444 DOI: 10.1186/s12934-020-01414-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Accepted: 07/20/2020] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND Furfural and 5-hydroxymethyl furfural (5-HMF) are key furan inhibitors that are generated due to breakdown of lignocellulosic sugars at high temperature and acidic treatment conditions. Both furfural and 5-HMF act in a synergistic manner to inhibit microbial metabolism and resistance to both is a desirable characteristic for efficient conversion of lignocellulosic carbon to ethanol. Genetic manipulations targeted toward increasing cellular NADPH pools have successfully imparted tolerance against furfural and 5-HMF. In present study, deletion of pgi gene as a strategy to augment carbon flow through pentose phosphate pathway (PPP) was studied in ethanologenic Escherichia coli strain SSK101 to impart tolerance towards either furfural or 5-HMFor both inhibitors together. RESULTS A key gene of EMP pathway, pgi, was deleted in an ethanologenic E. coli strain SSK42 to yield strain SSK101. In presence of 1 g/L furfural in minimal AM1 media, the rate of biomass formation for strain SSK101 was up to 1.9-fold higher as compared to parent SSK42 strain, and it was able to clear furfural in half the time. Tolerance to inhibitor was associated with glucose as carbon source and not xylose, and the tolerance advantage of SSK101 was neutralized in LB media. Bioreactor studies were performed under binary stress of furfural and 5-HMF (1 g/L each) and different glucose concentrations in a glucose-xylose mixture with final sugar concentration of 5.5%, mimicking major components of dilute acid treated biomass hydrolysate. In the mixture having 6 g/L and 12 g/L glucose, SSK101 strain produced ~ 18 g/L and 20 g/L ethanol, respectively. Interestingly, the maximum ethanol productivity was better at lower glucose load with 0.46 g/(L.h) between 96 and 120 h, as compared to higher glucose load where it was 0.33 g/(L.h) between 144 and 168 h. Importantly, parent strain SSK42 did not exhibit significant metabolic activity under similar conditions of inhibitor load and sugar concentration. CONCLUSIONS E. coli strain SSK101 with pgi deletion had enhanced tolerance against both furfural and 5-HMF, which was associated with presence of glucose in media. Strain SSK101 also had improved fermentation characteristics under both hyperosmotic as well as binary stress of furfural and 5-HMF in media containing glucose-xylose mixture.
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Affiliation(s)
- Syed Bilal Jilani
- Microbial Engineering Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), Aruna Asaf Ali Marg, New Delhi, India
- DBT-ICGEB Centre for Advanced Bioenergy Research, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
- Institute of Biotechnology, Amity University, Manesar, Haryana India
| | - Chandra Dev
- Microbial Engineering Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), Aruna Asaf Ali Marg, New Delhi, India
- DBT-ICGEB Centre for Advanced Bioenergy Research, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
| | - Danish Eqbal
- Microbial Engineering Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), Aruna Asaf Ali Marg, New Delhi, India
- DBT-ICGEB Centre for Advanced Bioenergy Research, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
| | - Kamran Jawed
- Microbial Engineering Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), Aruna Asaf Ali Marg, New Delhi, India
- DBT-ICGEB Centre for Advanced Bioenergy Research, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
- Present Address: Biodiscovery Institute, School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Rajendra Prasad
- Institute of Biotechnology, Amity University, Manesar, Haryana India
| | - Syed Shams Yazdani
- Microbial Engineering Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), Aruna Asaf Ali Marg, New Delhi, India
- DBT-ICGEB Centre for Advanced Bioenergy Research, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
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Production of Ethanol from Hemicellulosic Sugars of Exhausted Olive Pomace by Escherichia coli. Processes (Basel) 2020. [DOI: 10.3390/pr8050533] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Exhausted olive pomace (EOP) is the main residue generated in olive oil industries, after the extraction of the residual oil from olive pomace with hexane. This work studies the ethanol production from hemicellulosic sugars of EOP. The fermentability of the sugar solution, resulting from the acid pretreatment of EOP, was evaluated using Escherichia coli SL100, although a detoxification step was required before fermentation. Overliming and activated charcoal detoxification were tested to minimize the presence of inhibitory compounds in the hydrolysate and to achieve a fermentable medium. E. coli assimilated all sugars in both detoxified hydrolysates and achieved ethanol yields of about 90% of the theoretical one. However, the fermentation time was much shorter when the hydrolysate had been detoxified with activated charcoal (20 h versus 120 h).
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10
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Rojas-Chamorro JA, Romero-García JM, Cara C, Romero I, Castro E. Improved ethanol production from the slurry of pretreated brewers' spent grain through different co-fermentation strategies. BIORESOURCE TECHNOLOGY 2020; 296:122367. [PMID: 31727558 DOI: 10.1016/j.biortech.2019.122367] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 10/31/2019] [Accepted: 11/01/2019] [Indexed: 06/10/2023]
Abstract
The aim of this work was to bioconvert all sugars in BSG into ethanol using a process scheme that includes the enzymatic hydrolysis of the whole slurry resulting from the pretreatment of BSG with phosphoric and sulfuric acid using previously optimised conditions, followed by the co-fermentation of the mixed sugars. More than 90% of the sugars in raw BSG were recovered in the pretreatment and the subsequent enzymatic hydrolysis of the whole slurry. The co-fermentation of the enzymatic hydrolysates with Escherichia coli was then compared with that the co-culture of Scheffersomyces stipitis and Saccharomyces cerevisiae, which resulted in lower ethanol production. The co-fermentation strategy with a single microorganism (E. coli) when BSG was pretreated with phosphoric acid resulted into the highest ethanol concentration, 39 g/L, which means that 222 L of ethanol can be obtained from a ton of BSG without detoxification requirements.
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Affiliation(s)
- J A Rojas-Chamorro
- Dpt. Chemical, Environmental and Materials Engineering, Universidad de Jaén, Spain
| | - J M Romero-García
- Dpt. Chemical, Environmental and Materials Engineering, Universidad de Jaén, Spain; Center for Advanced Studies in Energy and Environment, Universidad de Jaén, Campus las Lagunillas, 23071 Jaén, Spain
| | - C Cara
- Dpt. Chemical, Environmental and Materials Engineering, Universidad de Jaén, Spain; Center for Advanced Studies in Energy and Environment, Universidad de Jaén, Campus las Lagunillas, 23071 Jaén, Spain
| | - I Romero
- Dpt. Chemical, Environmental and Materials Engineering, Universidad de Jaén, Spain; Center for Advanced Studies in Energy and Environment, Universidad de Jaén, Campus las Lagunillas, 23071 Jaén, Spain.
| | - E Castro
- Dpt. Chemical, Environmental and Materials Engineering, Universidad de Jaén, Spain; Center for Advanced Studies in Energy and Environment, Universidad de Jaén, Campus las Lagunillas, 23071 Jaén, Spain
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11
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Flores AD, Ayla EZ, Nielsen DR, Wang X. Engineering a Synthetic, Catabolically Orthogonal Coculture System for Enhanced Conversion of Lignocellulose-Derived Sugars to Ethanol. ACS Synth Biol 2019; 8:1089-1099. [PMID: 30979337 DOI: 10.1021/acssynbio.9b00007] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Fermentation of lignocellulosic sugar mixtures is often suboptimal due to inefficient xylose catabolism and sequential sugar utilization caused by carbon catabolite repression. Unlike in conventional applications employing a single engineered strain, the alternative development of synthetic microbial communities facilitates the execution of complex metabolic tasks by exploiting the unique community features, including modularity, division of labor, and facile tunability. A series of synthetic, catabolically orthogonal coculture systems were systematically engineered, as derived from either wild-type Escherichia coli W or ethanologenic LY180. Net catabolic activities were effectively balanced by simple tuning of the inoculum ratio between specialist strains, which enabled coutilization (98% of 100 g L-1 total sugars) of glucose-xylose mixtures (2:1 by mass) for both culture systems in simple batch fermentations. The engineered ethanologenic cocultures achieved ethanol titer (46 g L-1), productivity (488 mg L-1 h-1), and yield (∼90% of theoretical maximum), which were all significantly increased compared to LY180 monocultures.
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Affiliation(s)
- Andrew D. Flores
- Chemical Engineering, School for Engineering of Matter, Transport, and Energy, Arizona State University, ECG 301, 501 E. Tyler Mall, Tempe, Arizona 85287, United States
| | - E. Zeynep Ayla
- Chemical Engineering, School for Engineering of Matter, Transport, and Energy, Arizona State University, ECG 301, 501 E. Tyler Mall, Tempe, Arizona 85287, United States
| | - David R. Nielsen
- Chemical Engineering, School for Engineering of Matter, Transport, and Energy, Arizona State University, ECG 301, 501 E. Tyler Mall, Tempe, Arizona 85287, United States
| | - Xuan Wang
- School of Life Sciences, Arizona State University, 427 E. Tyler Mall, Tempe, Arizona 85287, United States
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12
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Wang L, York SW, Ingram LO, Shanmugam KT. Simultaneous fermentation of biomass-derived sugars to ethanol by a co-culture of an engineered Escherichia coli and Saccharomyces cerevisiae. BIORESOURCE TECHNOLOGY 2019; 273:269-276. [PMID: 30448678 DOI: 10.1016/j.biortech.2018.11.016] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Revised: 11/04/2018] [Accepted: 11/05/2018] [Indexed: 06/09/2023]
Abstract
Microorganisms ferment xylose at high rate only when glucose concentration in the medium falls below a critical level. Since the specific productivity of product is highest during exponential to early stationary phase of growth, a glucose utilization negative ethanologenic E. coli (strain LW419a) was constructed for high rate of xylose fermentation in combination with Turbo yeast. This co-culture fermented all the released sugars in an acid/enzyme-treated sugar cane bagasse slurry (10% solids) to an ethanol titer of 24.9 ± 0.8 g.L-1 (70% of the theoretical yield) in <30 h. Ethanol titer increased to 48.6 ± 1.04 g.L-1 (yield, 0.45 g.g-1 sugars) at a solids content of 20% and the highest rate of xylose consumption was 1.58 ± 0.21 g.L-1.h-1. This study demonstrates the potential of a co-culture of strain LW419a and yeast to rapidly ferment all the sugars in pretreated biomass slurries to ethanol at their respective highest rates.
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Affiliation(s)
- Liang Wang
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL 32611, United States.
| | - Sean W York
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL 32611, United States.
| | - Lonnie O Ingram
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL 32611, United States.
| | - K T Shanmugam
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL 32611, United States.
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13
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Martínez-Patiño JC, Ruiz E, Cara C, Romero I, Castro E. Advanced bioethanol production from olive tree biomass using different bioconversion schemes. Biochem Eng J 2018. [DOI: 10.1016/j.bej.2018.06.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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14
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Zebec Z, Scrutton NS. Genome Editing for the Production of Natural Products inEscherichia coli. ACTA ACUST UNITED AC 2018. [DOI: 10.1002/adbi.201800056] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- Ziga Zebec
- Manchester Institute of Biotechnology and School of Chemistry; The University of Manchester; Manchester M1 7DN UK
| | - Nigel S. Scrutton
- Manchester Institute of Biotechnology and School of Chemistry; The University of Manchester; Manchester M1 7DN UK
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15
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Ethanol Production by Soy Fiber Treatment and Simultaneous Saccharification and Co-Fermentation in an Integrated Corn-Soy Biorefinery. FERMENTATION-BASEL 2018. [DOI: 10.3390/fermentation4020035] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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16
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Wu W, Rondon V, Weeks K, Pullammanappallil P, Ingram LO, Shanmugam KT. Phosphoric acid based pretreatment of switchgrass and fermentation of entire slurry to ethanol using a simplified process. BIORESOURCE TECHNOLOGY 2018; 251:171-180. [PMID: 29274857 DOI: 10.1016/j.biortech.2017.12.041] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 12/13/2017] [Accepted: 12/14/2017] [Indexed: 05/21/2023]
Abstract
Switchgrass (Alamo) was pretreated with phosphoric acid (0.75 and 1%, w/w) at three temperatures (160, 175 and 190 °C) and time (5, 7.5 and 10 min) using a steam gun. The slurry after pretreatment was liquefied by enzymes and the released sugars were fermented in a simultaneous saccharification and co-fermentation process to ethanol using ethanologenic Escherichia coli strain SL100. Among the three variables in pretreatment, temperature and time were critical in supporting ethanol titer and yield. Enzyme hydrolysis significantly increased the concentration of furans in slurries, apparently due to release of furans bound to the solids. The highest ethanol titer of 21.2 ± 0.3 g/L ethanol obtained at the pretreatment condition of 190-1-7.5 (temperature-acid concentration-time) and 10% solids loading accounted for 190 ± 2.9 g ethanol/kg of raw switch grass. This converts to 61.7 gallons of ethanol per ton of dry switchgrass, a value that is comparable to other published pretreatment conditions.
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Affiliation(s)
- Wei Wu
- Department of Microbiology and Cell Science, Gainesville, FL 32611, United States; Department of Agricultural and Biological Engineering, Gainesville, FL 32611, United States
| | - Vanessa Rondon
- Department of Microbiology and Cell Science, Gainesville, FL 32611, United States; Stan Mayfield Biorefinery, University of Florida, Gainesville, FL 32611, United States
| | - Kalvin Weeks
- Stan Mayfield Biorefinery, University of Florida, Gainesville, FL 32611, United States
| | | | - Lonnie O Ingram
- Department of Microbiology and Cell Science, Gainesville, FL 32611, United States; Stan Mayfield Biorefinery, University of Florida, Gainesville, FL 32611, United States
| | - K T Shanmugam
- Department of Microbiology and Cell Science, Gainesville, FL 32611, United States.
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17
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Martínez-Patiño JC, Ruiz E, Romero I, Cara C, López-Linares JC, Castro E. Combined acid/alkaline-peroxide pretreatment of olive tree biomass for bioethanol production. BIORESOURCE TECHNOLOGY 2017; 239:326-335. [PMID: 28531858 DOI: 10.1016/j.biortech.2017.04.102] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Revised: 04/24/2017] [Accepted: 04/25/2017] [Indexed: 06/07/2023]
Abstract
Olive tree biomass (OTB) can be used for producing second generation bioethanol. In this work, extracted OTB was subjected to fractionation using a sequential acid/alkaline oxidative pretreatment. In the first acid stage, the effects of sulfuric acid concentration and reaction times at 130°C were investigated. Up to 71% solubilization of hemicellulosic sugars was achieved under optimized conditions (2.4% H2SO4, 84min). In the second stage, the influence of hydrogen peroxide concentration and process time were evaluated at 80°C. Approximately 80% delignification was achieved under the best operational conditions (7% H2O2, 90min) within the experimental range studied. This pretreatment produced a substrate with 72% cellulose that was highly accessible to enzymatic attack, yielding 82g glucose/100g glucose in delignified OTB. Ethanol production from both hemicellulosic sugars solubilized in the acid pretreatment and glucose from enzymatic hydrolysis of delignified OTB yielded 15g ethanol/100g OTB.
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Affiliation(s)
- José Carlos Martínez-Patiño
- Centre for Advanced Studies in Energy and Environment, University of Jaén, Campus Las Lagunillas, 23071 Jaén, Spain
| | - Encarnación Ruiz
- Centre for Advanced Studies in Energy and Environment, University of Jaén, Campus Las Lagunillas, 23071 Jaén, Spain
| | - Inmaculada Romero
- Centre for Advanced Studies in Energy and Environment, University of Jaén, Campus Las Lagunillas, 23071 Jaén, Spain.
| | - Cristóbal Cara
- Centre for Advanced Studies in Energy and Environment, University of Jaén, Campus Las Lagunillas, 23071 Jaén, Spain
| | - Juan Carlos López-Linares
- Centre for Advanced Studies in Energy and Environment, University of Jaén, Campus Las Lagunillas, 23071 Jaén, Spain
| | - Eulogio Castro
- Centre for Advanced Studies in Energy and Environment, University of Jaén, Campus Las Lagunillas, 23071 Jaén, Spain
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18
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Experimental evolution reveals an effective avenue to release catabolite repression via mutations in XylR. Proc Natl Acad Sci U S A 2017; 114:7349-7354. [PMID: 28655843 DOI: 10.1073/pnas.1700345114] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Microbial production of fuels and chemicals from lignocellulosic biomass provides promising biorenewable alternatives to the conventional petroleum-based products. However, heterogeneous sugar composition of lignocellulosic biomass hinders efficient microbial conversion due to carbon catabolite repression. The most abundant sugar monomers in lignocellulosic biomass materials are glucose and xylose. Although industrial Escherichia coli strains efficiently use glucose, their ability to use xylose is often repressed in the presence of glucose. Here we independently evolved three E. coli strains from the same ancestor to achieve high efficiency for xylose fermentation. Each evolved strain has a point mutation in a transcriptional activator for xylose catabolic operons, either CRP or XylR, and these mutations are demonstrated to enhance xylose fermentation by allelic replacements. Identified XylR variants (R121C and P363S) have a higher affinity to their DNA binding sites, leading to a xylose catabolic activation independent of catabolite repression control. Upon introducing these amino acid substitutions into the E. coli D-lactate producer TG114, 94% of a glucose-xylose mixture (50 g⋅L-1 each) was used in mineral salt media that led to a 50% increase in product titer after 96 h of fermentation. The two amino acid substitutions in XylR enhance xylose utilization and release glucose-induced repression in different E. coli hosts, including wild type, suggesting its potential wide application in industrial E. coli biocatalysts.
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19
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Su H, Lin J, Wang Y, Chen Q, Wang G, Tan F. Engineering Brevibacterium flavum
for the production of renewable bioenergy: C4-C5 advanced alcohols. Biotechnol Bioeng 2017; 114:1946-1958. [DOI: 10.1002/bit.26324] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Revised: 04/18/2017] [Accepted: 04/26/2017] [Indexed: 12/30/2022]
Affiliation(s)
- HaiFeng Su
- Chongqing Institute of Green and Interligent Technology; Chinese Academy of Science; 266, Fangzheng Avenue, Shuitu High-Tech Park, Beibei Chongqing 400714 P. R. China
| | - JiaFu Lin
- Antibiotics Research and Re-evaluation Key Laboratory of Sichuan Province; Sichuan Industrial Institute of Antibiotics, Chengdu University; Chengdu P. R. China
| | - YuanHong Wang
- Center of Analysis and Testing; School of Public Health; Institute of Analytical Chemistry for Life Science; Nantong University; Nantong P. R. China
| | - Qiao Chen
- Chongqing Institute of Green and Interligent Technology; Chinese Academy of Science; 266, Fangzheng Avenue, Shuitu High-Tech Park, Beibei Chongqing 400714 P. R. China
| | - GuangWei Wang
- Chongqing Institute of Green and Interligent Technology; Chinese Academy of Science; 266, Fangzheng Avenue, Shuitu High-Tech Park, Beibei Chongqing 400714 P. R. China
| | - FuRong Tan
- Biogas Institute of Ministry of Agriculture; Chengdu 610041 Sichuan P. R. China
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20
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Gubicza K, Nieves IU, Sagues WJ, Barta Z, Shanmugam KT, Ingram LO. Techno-economic analysis of ethanol production from sugarcane bagasse using a Liquefaction plus Simultaneous Saccharification and co-Fermentation process. BIORESOURCE TECHNOLOGY 2016; 208:42-48. [PMID: 26918837 DOI: 10.1016/j.biortech.2016.01.093] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Revised: 01/22/2016] [Accepted: 01/25/2016] [Indexed: 06/05/2023]
Abstract
A techno-economic analysis was conducted for a simplified lignocellulosic ethanol production process developed and proven by the University of Florida at laboratory, pilot, and demonstration scales. Data obtained from all three scales of development were used with Aspen Plus to create models for an experimentally-proven base-case and 5 hypothetical scenarios. The model input parameters that differed among the hypothetical scenarios were fermentation time, enzyme loading, enzymatic conversion, solids loading, and overall process yield. The minimum ethanol selling price (MESP) varied between 50.38 and 62.72 US cents/L. The feedstock and the capital cost were the main contributors to the production cost, comprising between 23-28% and 40-49% of the MESP, respectively. A sensitivity analysis showed that overall ethanol yield had the greatest effect on the MESP. These findings suggest that future efforts to increase the economic feasibility of a cellulosic ethanol process should focus on optimization for highest ethanol yield.
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Affiliation(s)
- Krisztina Gubicza
- Department of Applied Biotechnology and Food Science, Faculty of Chemical Technology and Biotechnology, Budapest University of Technology and Economics, H-1111 Budapest, Muegyetem rkp. 3, Hungary
| | - Ismael U Nieves
- Stan Mayfield Biorefinery, University of Florida, Perry, FL 32348, United States
| | - William J Sagues
- Stan Mayfield Biorefinery, University of Florida, Perry, FL 32348, United States
| | - Zsolt Barta
- Department of Applied Biotechnology and Food Science, Faculty of Chemical Technology and Biotechnology, Budapest University of Technology and Economics, H-1111 Budapest, Muegyetem rkp. 3, Hungary
| | - K T Shanmugam
- Stan Mayfield Biorefinery, University of Florida, Perry, FL 32348, United States; Microbiology & Cell Science, University of Florida, Gainesville, FL 32611-0700, United States
| | - Lonnie O Ingram
- Stan Mayfield Biorefinery, University of Florida, Perry, FL 32348, United States; Microbiology & Cell Science, University of Florida, Gainesville, FL 32611-0700, United States.
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21
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Cellulases: Classification, Methods of Determination and Industrial Applications. Appl Biochem Biotechnol 2016; 179:1346-80. [PMID: 27068832 DOI: 10.1007/s12010-016-2070-3] [Citation(s) in RCA: 87] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Accepted: 03/31/2016] [Indexed: 10/22/2022]
Abstract
Microbial cellulases have been receiving worldwide attention, as they have enormous potential to process the most abundant cellulosic biomass on this planet and transform it into sustainable biofuels and other value added products. The synergistic action of endoglucanases, exoglucanases, and β-glucosidases is required for the depolymerization of cellulose to fermentable sugars for transformation in to useful products using suitable microorganisms. The lack of a better understanding of the mechanisms of individual cellulases and their synergistic actions is the major hurdles yet to be overcome for large-scale commercial applications of cellulases. We have reviewed various microbial cellulases with a focus on their classification with mechanistic aspects of cellulase hydrolytic action, insights into novel approaches for determining cellulase activity, and potential industrial applications of cellulases.
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22
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Romero-García J, Martínez-Patiño C, Ruiz E, Romero I, Castro E. Ethanol production from olive stone hydrolysates by xylose fermenting microorganisms. ACTA ACUST UNITED AC 2016. [DOI: 10.1515/bioeth-2016-0002] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
AbstractOlive stones are the main solid byproducts obtained from olive oil production and from table olives production. As a lignocellulosic material, the use of olive stones for ethanol and other chemicals production has been proposed, particularly under the biorefinery concept. As part of such a process, this work deals with the fractionation of the lignocellulosic material by dilute acid autoclave pretreatment at 2% sulfuric acid, 130°C, 60 min and 1:1 liquid to solid ratio. Moreover, the work addresses the fermentation of the liquors obtained after pretreatment. The released sugars are composed mainly by xylose and other hemicellulosic sugars. The fermentation performance of three xylose-fermenting microorganisms, e.g. two Escherichia coli species and Scheffersomyces stipitis, are compared. The study analyzes in a first step the microorganism behavior on synthetic liquors, with a similar composition to that of the real liquors. Finally, and taken into account the results from the previous steps, the real liquor obtained from olive stones pretreatment is fermented. Results show that E. coli MM160 is the best ethanol producer out of the three microorganisms studied. Globally, the pretreatment produced a liquor containing 140 g hemicellulosic sugars/l and requiring firstly dilution by 50% and a detoxification step by overliming. The fermentation of this liquor by E. coli MM160 results in a 25 g ethanol/l solution equivalent to 50 g ethanol/kg olive stone, in spite of 20 g acetic acid/l also present. These results confirm both olive stones and E. coli MM160 as promising feedstock and microorganism for ethanol production.
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23
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Si HM, Zhang F, Wu AN, Han RZ, Xu GC, Ni Y. DNA microarray of global transcription factor mutant reveals membrane-related proteins involved in n-butanol tolerance in Escherichia coli. BIOTECHNOLOGY FOR BIOFUELS 2016; 9:114. [PMID: 27252779 PMCID: PMC4888631 DOI: 10.1186/s13068-016-0527-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Accepted: 05/11/2016] [Indexed: 05/07/2023]
Abstract
BACKGROUND Escherichia coli has been explored as a platform host strain for biofuels production such as butanol. However, the severe toxicity of butanol is considered to be one major limitation for butanol production from E. coli. The goal of this study is therefore to construct butanol-tolerant E. coli strains and clarify the tolerance mechanisms. RESULTS A recombinant E. coli strain harboring σ(70) mutation capable of tolerating 2 % (v/v) butanol was isolated by the global transcription machinery engineering (gTME) approach. DNA microarrays were employed to assess the transcriptome profile of butanol-tolerant strain B8. Compared with the wild-type strain, 329 differentially expressed genes (197 up-regulated and 132 down-regulated) (p < 0.05; FC ≥ 2) were identified. These genes are involved in carbohydrate metabolism, energy metabolism, two-component signal transduction system, oxidative stress response, lipid and cell envelope biogenesis and efflux pump. CONCLUSIONS Several membrane-related proteins were proved to be involved in butanol tolerance of E. coli. Two down-regulated genes, yibT and yghW, were identified to be capable of affecting butanol tolerance by regulating membrane fatty acid composition. Another down-regulated gene ybjC encodes a predicted inner membrane protein. In addition, a number of up-regulated genes, such as gcl and glcF, contribute to supplement metabolic intermediates for glyoxylate and TCA cycles to enhance energy supply. Our results could serve as a practical strategy for the construction of platform E. coli strains as biofuel producer.
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Affiliation(s)
- Hai-Ming Si
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122 Jiangsu China
| | - Fa Zhang
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122 Jiangsu China
| | - An-Ning Wu
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122 Jiangsu China
| | - Rui-Zhi Han
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122 Jiangsu China
| | - Guo-Chao Xu
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122 Jiangsu China
| | - Ye Ni
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122 Jiangsu China
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24
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Wang L, Ou MS, Nieves I, Erickson JE, Vermerris W, Ingram LO, Shanmugam KT. Fermentation of sweet sorghum derived sugars to butyric acid at high titer and productivity by a moderate thermophile Clostridium thermobutyricum at 50°C. BIORESOURCE TECHNOLOGY 2015; 198:533-539. [PMID: 26432057 DOI: 10.1016/j.biortech.2015.09.062] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Revised: 09/11/2015] [Accepted: 09/13/2015] [Indexed: 06/05/2023]
Abstract
In this study, a moderate thermophile Clostridium thermobutyricum is shown to ferment the sugars in sweet sorghum juice treated with invertase and supplemented with tryptone (10 g L(-1)) and yeast extract (10 g L(-1)) at 50°C to 44 g L(-1) butyrate at a calculated highest volumetric productivity of 1.45 g L(-1)h(-1) (molar butyrate yield of 0.85 based on sugars fermented). This volumetric productivity is among the highest reported for batch fermentations. Sugars from acid and enzyme-treated sweet sorghum bagasse were also fermented to butyrate by this organism with a molar yield of 0.81 (based on the amount of cellulose and hemicellulose). By combining the results from juice and bagasse, the calculated yield of butyric acid is approximately 90 kg per tonne of fresh sweet sorghum stalk. This study demonstrates that C. thermobutyricum can be an effective microbial biocatalyst for production of bio-based butyrate from renewable feedstocks at 50°C.
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Affiliation(s)
- Liang Wang
- Department of Microbiology and Cell Science, IFAS, University of Florida, Gainesville, FL 32611, USA
| | - Mark S Ou
- Department of Microbiology and Cell Science, IFAS, University of Florida, Gainesville, FL 32611, USA
| | - Ismael Nieves
- Department of Microbiology and Cell Science, IFAS, University of Florida, Gainesville, FL 32611, USA
| | - John E Erickson
- Department of Agronomy, IFAS, University of Florida, Gainesville, FL 32611, USA
| | - Wilfred Vermerris
- Department of Microbiology and Cell Science, IFAS, University of Florida, Gainesville, FL 32611, USA
| | - L O Ingram
- Department of Microbiology and Cell Science, IFAS, University of Florida, Gainesville, FL 32611, USA
| | - K T Shanmugam
- Department of Microbiology and Cell Science, IFAS, University of Florida, Gainesville, FL 32611, USA.
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25
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Liu J, Chen S, Ding J, Xiao Y, Han H, Zhong G. Sugarcane bagasse as support for immobilization of Bacillus pumilus HZ-2 and its use in bioremediation of mesotrione-contaminated soils. Appl Microbiol Biotechnol 2015; 99:10839-51. [PMID: 26337896 DOI: 10.1007/s00253-015-6935-0] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Revised: 07/21/2015] [Accepted: 08/11/2015] [Indexed: 11/26/2022]
Abstract
The degrading microorganisms isolated from environment usually fail to degrade pollutants when used for bioremediation of contaminated soils; thus, additional treatments are needed to enhance biodegradation. In the present study, the potential of sugarcane bagasse as bacteria-immobilizing support was investigated in mesotrione biodegradation. A novel isolate Bacillus pumilus HZ-2 was applied in bacterial immobilization, which was capable of degrading over 95 % of mesotrione at initial concentrations ranging from 25 to 200 mg L(-1) within 4 days in flask-shaking tests. Scanning electron microscope (SEM) images showed that the bacterial cells were strongly absorbed and fully dispersed on bagasse surface after immobilization. Specially, 86.5 and 82.9 % of mesotrione was eliminated by bacteria immobilized on bagasse of 100 and 60 mesh, respectively, which indicated that this immobilization was able to maintain a high degrading activity of the bacteria. Analysis of the degradation products determined 2-amino-4-methylsulfonylbenzoic acid (AMBA) and 4-methylsulfonyl-2-nitrobenzoic acid (MNBA) as the main metabolites in the biodegradation pathway of mesotrione. In the sterile soil, approximately 90 % of mesotrione was degraded after supplementing 5.0 % of molasses in bacteria-bagasse composite, which greatly enhanced microbial adaptability and growth in the soil environment. In the field tests, over 75 % of mesotrione in soil was degraded within 14 days. The immobilized preparation demonstrated that mesotrione could be degraded at a wide range of pH values (5.0-8.0) and temperatures (25-35 °C), especially at low concentrations of mesotrione (5 to 20 mg kg(-1)). These results showed that sugarcane bagasse might be a good candidate as bacteria-immobilizing support to enhance mesotrione degradation by Bacillus p. HZ-2 in contaminated soils.
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Affiliation(s)
- Jie Liu
- Key Laboratory of Natural Pesticide and Chemical Biology, Ministry of Education, and Lab of Insect Toxicology, South China Agricultural University, Guangzhou, 510642, People's Republic of China
| | - Shaohua Chen
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, 510642, People's Republic of China
| | - Jie Ding
- Key Laboratory of Natural Pesticide and Chemical Biology, Ministry of Education, and Lab of Insect Toxicology, South China Agricultural University, Guangzhou, 510642, People's Republic of China
| | - Ying Xiao
- Key Laboratory of Natural Pesticide and Chemical Biology, Ministry of Education, and Lab of Insect Toxicology, South China Agricultural University, Guangzhou, 510642, People's Republic of China
| | - Haitao Han
- Key Laboratory of Natural Pesticide and Chemical Biology, Ministry of Education, and Lab of Insect Toxicology, South China Agricultural University, Guangzhou, 510642, People's Republic of China
| | - Guohua Zhong
- Key Laboratory of Natural Pesticide and Chemical Biology, Ministry of Education, and Lab of Insect Toxicology, South China Agricultural University, Guangzhou, 510642, People's Republic of China.
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26
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Tanaka T, Kondo A. Cell surface engineering of industrial microorganisms for biorefining applications. Biotechnol Adv 2015; 33:1403-11. [PMID: 26070720 DOI: 10.1016/j.biotechadv.2015.06.002] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2014] [Revised: 06/04/2015] [Accepted: 06/06/2015] [Indexed: 11/19/2022]
Abstract
In order to decrease carbon emissions and negative environmental impacts of various pollutants, biofuel/biochemical production should be promoted for replacing fossil-based industrial processes. Utilization of abundant lignocellulosic biomass as a feedstock has recently become an attractive option. In this review, we focus on recent efforts of cell surface display using industrial microorganisms such as Escherichia coli and yeast. Cell surface display is used primarily for endowing cellulolytic activity on the host cells, and enables direct fermentation to generate useful fuels and chemicals from lignocellulosic biomass. Cell surface display systems are systematically summarized, and the drawbacks/perspectives as well as successful application of surface display for industrial biotechnology are discussed.
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Affiliation(s)
- Tsutomu Tanaka
- Department of Chemical Science and Technology, Graduate School of Engineering, Kobe University, 1-1, Rokkodaicho, Nada, Kobe 657-8501 Japan
| | - Akihiko Kondo
- Department of Chemical Science and Technology, Graduate School of Engineering, Kobe University, 1-1, Rokkodaicho, Nada, Kobe 657-8501 Japan.
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27
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Nieves LM, Panyon LA, Wang X. Engineering Sugar Utilization and Microbial Tolerance toward Lignocellulose Conversion. Front Bioeng Biotechnol 2015; 3:17. [PMID: 25741507 PMCID: PMC4332379 DOI: 10.3389/fbioe.2015.00017] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Accepted: 02/04/2015] [Indexed: 12/22/2022] Open
Abstract
Production of fuels and chemicals through a fermentation-based manufacturing process that uses renewable feedstock such as lignocellulosic biomass is a desirable alternative to petrochemicals. Although it is still in its infancy, synthetic biology offers great potential to overcome the challenges associated with lignocellulose conversion. In this review, we will summarize the identification and optimization of synthetic biological parts used to enhance the utilization of lignocellulose-derived sugars and to increase the biocatalyst tolerance for lignocellulose-derived fermentation inhibitors. We will also discuss the ongoing efforts and future applications of synthetic integrated biological systems used to improve lignocellulose conversion.
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Affiliation(s)
- Lizbeth M Nieves
- School of Life Sciences, Arizona State University , Tempe, AZ , USA
| | - Larry A Panyon
- School of Life Sciences, Arizona State University , Tempe, AZ , USA
| | - Xuan Wang
- School of Life Sciences, Arizona State University , Tempe, AZ , USA
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Su H, Jiang J, Lu Q, Zhao Z, Xie T, Zhao H, Wang M. Engineering Corynebacterium crenatum to produce higher alcohols for biofuel using hydrolysates of duckweed (Landoltia punctata) as feedstock. Microb Cell Fact 2015; 14:16. [PMID: 25889648 PMCID: PMC4324788 DOI: 10.1186/s12934-015-0199-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2014] [Accepted: 01/26/2015] [Indexed: 11/10/2022] Open
Abstract
Early trials have demonstrated great potential for the use of duckweed (family Lemnaceae) as the next generation of energy plants for the production of biofuels. Achieving this technological advance demands research to develop novel bioengineering microorganisms that can ferment duckweed feedstock to produce higher alcohols. In this study, we used relevant genes to transfer five metabolic pathways of isoleucine, leucine and valine from the yeast Saccharomyces cerevisiae into the bioengineered microorganism Corynebacterium crenatum. Experimental results showed that the bioengineered strain was able to produce 1026.61 mg/L of 2-methyl-1-butanol by fermenting glucose, compared to 981.79 mg/L from the acid hydrolysates of duckweed. The highest isobutanol yields achieved were 1264.63 mg/L from glucose and 1154.83 mg/L from duckweed, and the corresponding highest yields of 3-methyl-1-butanol were 748.35 and 684.79 mg/L. Our findings demonstrate the feasibility of using bioengineered C. crenatum as a platform to construct a bacterial strain that is capable of producing higher alcohols. We have also shown the promise of using duckweed as the basis for developing higher alcohols, illustrating that this group of plants represents an ideal fermentation substrate that can be considered the next generation of alternative energy feedstocks.
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Affiliation(s)
- Haifeng Su
- Key Laboratory of Bio-resources and Eco-environment of the Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610064, Sichuan, PR China.
| | - Juan Jiang
- Key Laboratory of Bio-resources and Eco-environment of the Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610064, Sichuan, PR China.
| | - Qiuli Lu
- Key Laboratory of Bio-resources and Eco-environment of the Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610064, Sichuan, PR China.
| | - Zhao Zhao
- Key Laboratory of Bio-resources and Eco-environment of the Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610064, Sichuan, PR China.
| | - Tian Xie
- Key Laboratory of Bio-resources and Eco-environment of the Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610064, Sichuan, PR China.
| | - Hai Zhao
- Bioenergy Laboratory, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041, Sichuan, PR China.
| | - Maolin Wang
- Key Laboratory of Bio-resources and Eco-environment of the Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610064, Sichuan, PR China.
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Su H, Lu Q, Zhao Y, Jiang J, Zhao Z, Wang M. Preliminary investigation of metabolic engineering in a novel host bacterium Corynebacterium crenatum for alcohol biofuel production. RSC Adv 2014. [DOI: 10.1039/c4ra08668f] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
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Toward aldehyde and alkane production by removing aldehyde reductase activity in Escherichia coli. Metab Eng 2014; 25:227-37. [PMID: 25108218 DOI: 10.1016/j.ymben.2014.07.012] [Citation(s) in RCA: 101] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Revised: 06/30/2014] [Accepted: 07/30/2014] [Indexed: 01/15/2023]
Abstract
Advances in synthetic biology and metabolic engineering have enabled the construction of novel biological routes to valuable chemicals using suitable microbial hosts. Aldehydes serve as chemical feedstocks in the synthesis of rubbers, plastics, and other larger molecules. Microbial production of alkanes is dependent on the formation of a fatty aldehyde intermediate which is converted to an alkane by an aldehyde deformylating oxygenase (ADO). However, microbial hosts such as Escherichia coli are plagued by many highly active endogenous aldehyde reductases (ALRs) that convert aldehydes to alcohols, which greatly complicates strain engineering for aldehyde and alkane production. It has been shown that the endogenous ALR activity outcompetes the ADO enzyme for fatty aldehyde substrate. The large degree of ALR redundancy coupled with an incomplete database of ALRs represents a significant obstacle in engineering E. coli for either aldehyde or alkane production. In this study, we identified 44 ALR candidates encoded in the E. coli genome using bioinformatics tools, and undertook a comprehensive screening by measuring the ability of these enzymes to produce isobutanol. From the pool of 44 candidates, we found five new ALRs using this screening method (YahK, DkgA, GldA, YbbO, and YghA). Combined deletions of all 13 known ALRs resulted in a 90-99% reduction in endogenous ALR activity for a wide range of aldehyde substrates (C2-C12). Elucidation of the ALRs found in E. coli could guide one in reducing competing alcohol formation during alkane or aldehyde production.
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Förster AH, Gescher J. Metabolic Engineering of Escherichia coli for Production of Mixed-Acid Fermentation End Products. Front Bioeng Biotechnol 2014; 2:16. [PMID: 25152889 PMCID: PMC4126452 DOI: 10.3389/fbioe.2014.00016] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Accepted: 05/09/2014] [Indexed: 01/25/2023] Open
Abstract
Mixed-acid fermentation end products have numerous applications in biotechnology. This is probably the main driving force for the development of multiple strains that are supposed to produce individual end products with high yields. The process of engineering Escherichia coli strains for applied production of ethanol, lactate, succinate, or acetate was initiated several decades ago and is still ongoing. This review follows the path of strain development from the general characteristics of aerobic versus anaerobic metabolism over the regulatory machinery that enables the different metabolic routes. Thereafter, major improvements for broadening the substrate spectrum of E. coli toward cheap carbon sources like molasses or lignocellulose are highlighted before major routes of strain development for the production of ethanol, acetate, lactate, and succinate are presented.
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Affiliation(s)
- Andreas H Förster
- Institute of Applied Biosciences, Karlsruhe Institute of Technology , Karlsruhe , Germany
| | - Johannes Gescher
- Institute of Applied Biosciences, Karlsruhe Institute of Technology , Karlsruhe , Germany
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Zhang Y, Chen X, Luo J, Qi B, Wan Y. An efficient process for lactic acid production from wheat straw by a newly isolated Bacillus coagulans strain IPE22. BIORESOURCE TECHNOLOGY 2014; 158:396-9. [PMID: 24679663 DOI: 10.1016/j.biortech.2014.02.128] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2013] [Revised: 02/27/2014] [Accepted: 02/28/2014] [Indexed: 05/26/2023]
Abstract
A thermophilic lactic acid (LA) producer was isolated and identified as Bacillus coagulans strain IPE22. The strain showed remarkable capability to ferment pentose, hexose and cellobiose, and was also resistant to inhibitors from lignocellulosic hydrolysates. Based on the strain's promising features, an efficient process was developed to produce LA from wheat straw. The process consisted of biomass pretreatment by dilute sulfuric acid and subsequent SSCF (simultaneous saccharification and co-fermentation), while the operations of solid-liquid separation and detoxification were avoided. Using this process, 46.12 g LA could be produced from 100g dry wheat straw with a supplement of 10 g/L corn steep liquid powder at the cellulase loading of 20 FPU (filter paper activity units)/g cellulose. The process by B. coagulans IPE22 provides an economical route to produce LA from lignocellulose.
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Affiliation(s)
- Yuming Zhang
- State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China; University of the Chinese Academy of Sciences, Beijing 100049, China; College of Life Sciences, Hebei University, Baoding 071002, China
| | - Xiangrong Chen
- State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China
| | - Jianquan Luo
- Department of Chemical and Biochemical Engineering, Center for Bioprocess Engineering, Technical University of Denmark, Building 229, DK-2800 Kgs. Lyngby, Denmark
| | - Benkun Qi
- State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China
| | - Yinhua Wan
- State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China.
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Zeng J, Tong Z, Wang L, Zhu JY, Ingram L. Isolation and structural characterization of sugarcane bagasse lignin after dilute phosphoric acid plus steam explosion pretreatment and its effect on cellulose hydrolysis. BIORESOURCE TECHNOLOGY 2014; 154:274-81. [PMID: 24412855 DOI: 10.1016/j.biortech.2013.12.072] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2013] [Revised: 12/12/2013] [Accepted: 12/14/2013] [Indexed: 05/09/2023]
Abstract
The structure of lignin after dilute phosphoric acid plus steam explosion pretreatment process of sugarcane bagasse in a pilot scale and the effect of the lignin extracted by ethanol on subsequent cellulose hydrolysis were investigated. The lignin structural changes caused by pretreatment were identified using advanced nondestructive techniques such as gel permeation chromatography (GPC), quantitative (13)C, and 2-D nuclear magnetic resonance (NMR). The structural analysis revealed that ethanol extractable lignin preserved basic lignin structure, but had relatively lower amount of β-O-4 linkages, syringyl/guaiacyl units ratio (S/G), p-coumarate/ferulate ratio, and other ending structures. The results also indicated that approximately 8% of mass weight was extracted by pure ethanol. The bagasse after ethanol extraction had an approximate 22% higher glucose yield after enzyme hydrolysis compared to pretreated bagasse without extraction.
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Affiliation(s)
- Jijiao Zeng
- Department of Agriculture & Biological Engineering, IFAS, University of Florida, Gainesville, FL 32611, USA
| | - Zhaohui Tong
- Department of Agriculture & Biological Engineering, IFAS, University of Florida, Gainesville, FL 32611, USA.
| | - Letian Wang
- Department of Agriculture & Biological Engineering, IFAS, University of Florida, Gainesville, FL 32611, USA
| | - J Y Zhu
- USDA Forest Service, Forest Products Laboratory, One Gifford Pinchot Dr., Madison, WI 53726, USA
| | - Lonnie Ingram
- Department of Microbiology & Cell Science, University of Florida, PO Box 110700, Gainesville, FL 32606, USA
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Negro MJ, Alvarez C, Ballesteros I, Romero I, Ballesteros M, Castro E, Manzanares P, Moya M, Oliva JM. Ethanol production from glucose and xylose obtained from steam exploded water-extracted olive tree pruning using phosphoric acid as catalyst. BIORESOURCE TECHNOLOGY 2014; 153:101-107. [PMID: 24345569 DOI: 10.1016/j.biortech.2013.11.079] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Revised: 11/26/2013] [Accepted: 11/28/2013] [Indexed: 06/03/2023]
Abstract
In this work, the effect of phosphoric acid (1% w/w) in steam explosion pretreatment of water extracted olive tree pruning at 175°C and 195°C was evaluated. The objective is to produce ethanol from all sugars (mainly glucose and xylose) contained in the pretreated material. The water insoluble fraction obtained after pretreatment was used as substrate in a simultaneous saccharification and fermentation (SSF) process by a commercial strain of Saccharomyces cerevisiae. The liquid fraction, containing mainly xylose, was detoxified by alkali and ion-exchange resin and then fermented by the xylose fermenting yeast Scheffersomyces stipitis. Ethanol yields reached in a SSF process were close to 80% when using 15% (w/w) substrate consistency and about 70% of theoretical when using prehydrolysates detoxified by ion-exchange resins. Considering sugars recovery and ethanol yields about 160g of ethanol from kg of water extracted olive tree pruning could be obtained.
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Affiliation(s)
- M J Negro
- Biofuels Unit, DER-CIEMAT, Avda. Complutense 40, 28040 Madrid, Spain
| | - C Alvarez
- Biofuels Unit, DER-CIEMAT, Avda. Complutense 40, 28040 Madrid, Spain
| | - I Ballesteros
- Biofuels Unit, DER-CIEMAT, Avda. Complutense 40, 28040 Madrid, Spain
| | - I Romero
- Department of Chemical, Environmental and Materials Engineering, University of Jaen, Campus Las Lagunillas, 23071 Jaen, Spain
| | - M Ballesteros
- Biofuels Unit, DER-CIEMAT, Avda. Complutense 40, 28040 Madrid, Spain
| | - E Castro
- Department of Chemical, Environmental and Materials Engineering, University of Jaen, Campus Las Lagunillas, 23071 Jaen, Spain
| | - P Manzanares
- Biofuels Unit, DER-CIEMAT, Avda. Complutense 40, 28040 Madrid, Spain
| | - M Moya
- Department of Chemical, Environmental and Materials Engineering, University of Jaen, Campus Las Lagunillas, 23071 Jaen, Spain
| | - J M Oliva
- Biofuels Unit, DER-CIEMAT, Avda. Complutense 40, 28040 Madrid, Spain.
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Chen X, Zhou L, Tian K, Kumar A, Singh S, Prior BA, Wang Z. Metabolic engineering of Escherichia coli: A sustainable industrial platform for bio-based chemical production. Biotechnol Adv 2013; 31:1200-23. [DOI: 10.1016/j.biotechadv.2013.02.009] [Citation(s) in RCA: 117] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2012] [Revised: 02/04/2013] [Accepted: 02/25/2013] [Indexed: 12/20/2022]
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36
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Engineering of transcriptional regulators enhances microbial stress tolerance. Biotechnol Adv 2013; 31:986-91. [DOI: 10.1016/j.biotechadv.2013.02.010] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2012] [Revised: 01/17/2013] [Accepted: 02/25/2013] [Indexed: 11/20/2022]
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Optimization of Endoglucanase and Xylanase Activities from Fusarium verticillioides for Simultaneous Saccharification and Fermentation of Sugarcane Bagasse. Appl Biochem Biotechnol 2013; 172:1332-46. [DOI: 10.1007/s12010-013-0572-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Accepted: 09/30/2013] [Indexed: 10/26/2022]
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38
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Linville JL, Rodriguez M, Land M, Syed MH, Engle NL, Tschaplinski TJ, Mielenz JR, Cox CD. Industrial robustness: understanding the mechanism of tolerance for the Populus hydrolysate-tolerant mutant strain of Clostridium thermocellum. PLoS One 2013; 8:e78829. [PMID: 24205326 PMCID: PMC3804516 DOI: 10.1371/journal.pone.0078829] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Accepted: 09/16/2013] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND An industrially robust microorganism that can efficiently degrade and convert lignocellulosic biomass into ethanol and next-generation fuels is required to economically produce future sustainable liquid transportation fuels. The anaerobic, thermophilic, cellulolytic bacterium Clostridium thermocellum is a candidate microorganism for such conversions but it, like many bacteria, is sensitive to potential toxic inhibitors developed in the liquid hydrolysate produced during biomass processing. Microbial processes leading to tolerance of these inhibitory compounds found in the pretreated biomass hydrolysate are likely complex and involve multiple genes. METHODOLOGY/PRINCIPAL FINDINGS In this study, we developed a 17.5% v/v Populus hydrolysate tolerant mutant strain of C. thermocellum by directed evolution. The genome of the wild type strain, six intermediate population samples and seven single colony isolates were sequenced to elucidate the mechanism of tolerance. Analysis of the 224 putative mutations revealed 73 high confidence mutations. A longitudinal analysis of the intermediate population samples, a pan-genomic analysis of the isolates, and a hotspot analysis revealed 24 core genes common to all seven isolates and 8 hotspots. Genetic mutations were matched with the observed phenotype through comparison of RNA expression levels during fermentation by the wild type strain and mutant isolate 6 in various concentrations of Populus hydrolysate (0%, 10%, and 17.5% v/v). CONCLUSION/SIGNIFICANCE The findings suggest that there are multiple mutations responsible for the Populus hydrolysate tolerant phenotype resulting in several simultaneous mechanisms of action, including increases in cellular repair, and altered energy metabolism. To date, this study provides the most comprehensive elucidation of the mechanism of tolerance to a pretreated biomass hydrolysate by C. thermocellum. These findings make important contributions to the development of industrially robust strains of consolidated bioprocessing microorganisms.
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Affiliation(s)
- Jessica L Linville
- Department of Civil and Environmental Engineering, University of Tennessee, Knoxville, Tennessee, United States of America ; Bioenergy Science Center, Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States of America
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Polysaccharide hydrolysis with engineered Escherichia coli for the production of biocommodities. ACTA ACUST UNITED AC 2013; 40:401-10. [DOI: 10.1007/s10295-013-1245-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2012] [Accepted: 02/13/2013] [Indexed: 02/06/2023]
Abstract
Abstract
Escherichia coli can ferment a broad range of sugars, including pentoses, hexoses, uronic acids, and polyols. These features make E. coli a suitable microorganism for the development of biocatalysts to be used in the production of biocommodities and biofuels by metabolic engineering. E. coli cannot directly ferment polysaccharides because it does not produce and secrete the necessary saccharolytic enzymes; however, there are many genetic tools that can be used to confer this ability on this prokaryote. The construction of saccharolytic E. coli strains will reduce costs and simplify the production process because the saccharification and fermentation can be conducted in a single reactor with a reduced concentration or absence of additional external saccharolytic enzymes. Recent advances in metabolic engineering, surface display, and excretion of hydrolytic enzymes provide a framework for developing E. coli strains for the so-called consolidated bioprocessing. This review presents the different strategies toward the development of E. coli strains that have the ability to display and secrete saccharolytic enzymes to hydrolyze different sugar-polymeric substrates and reduce the loading of saccharolytic enzymes.
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Engineering furfural tolerance in Escherichia coli improves the fermentation of lignocellulosic sugars into renewable chemicals. Proc Natl Acad Sci U S A 2013; 110:4021-6. [PMID: 23431191 DOI: 10.1073/pnas.1217958110] [Citation(s) in RCA: 116] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Pretreatments such as dilute acid at elevated temperature are effective for the hydrolysis of pentose polymers in hemicellulose and also increase the access of enzymes to cellulose fibers. However, the fermentation of resulting syrups is hindered by minor reaction products such as furfural from pentose dehydration. To mitigate this problem, four genetic traits have been identified that increase furfural tolerance in ethanol-producing Escherichia coli LY180 (strain W derivative): increased expression of fucO, ucpA, or pntAB and deletion of yqhD. Plasmids and integrated strains were used to characterize epistatic interactions among traits and to identify the most effective combinations. Furfural resistance traits were subsequently integrated into the chromosome of LY180 to construct strain XW129 (LY180 ΔyqhD ackA::PyadC'fucO-ucpA) for ethanol. This same combination of traits was also constructed in succinate biocatalysts (Escherichia coli strain C derivatives) and found to increase furfural tolerance. Strains engineered for resistance to furfural were also more resistant to the mixture of inhibitors in hemicellulose hydrolysates, confirming the importance of furfural as an inhibitory component. With resistant biocatalysts, product yields (ethanol and succinate) from hemicellulose syrups were equal to control fermentations in laboratory media without inhibitors. The combination of genetic traits identified for the production of ethanol (strain W derivative) and succinate (strain C derivative) may prove useful for other renewable chemicals from lignocellulosic sugars.
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Wei D, Liu X, Yang ST. Butyric acid production from sugarcane bagasse hydrolysate by Clostridium tyrobutyricum immobilized in a fibrous-bed bioreactor. BIORESOURCE TECHNOLOGY 2013; 129:553-560. [PMID: 23270719 DOI: 10.1016/j.biortech.2012.11.065] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2012] [Revised: 11/10/2012] [Accepted: 11/16/2012] [Indexed: 06/01/2023]
Abstract
A fermentation process using Clostridium tyrobutyricum immobilized in a fibrous-bed bioreactor (FBB) was developed for butyric acid production from sugarcane bagasse (SCB) hydrolysate. SCB was first treated with dilute acid and then hydrolyzed with cellulases. The hydrolysate containing glucose and xylose was used as carbon source for the fermentation without detoxification. The bacterium was able to grow at a specific growth rate of ∼0.06 h(-1) in media containing 15-20% (w/v) SCB in serum bottles. In batch cultures in the FBB, both glucose and xylose in the SCB hydrolysate were simultaneously converted to butyrate with a high yield (0.45-0.54 g/gsugar) and productivity (0.48-0.60 g/Lh). A final butyrate concentration of 20.9 g/L was obtained in a fed-batch culture, with an overall productivity of 0.51 g/Lh and butyrate yield of 0.48 g/g sugar consumed. This work demonstrated the feasibility of using SCB as a low-cost feedstock to produce butyric acid.
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Affiliation(s)
- Dong Wei
- State Key Laboratory of Pulp and Paper Engineering, School of Light Industry and Food Sciences, South China University of Technology, Guangzhou 510640, PR China; William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, 140 West 19th Avenue, Columbus, OH 43210, USA.
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Yanagisawa M, Kawai S, Murata K. Strategies for the production of high concentrations of bioethanol from seaweeds: production of high concentrations of bioethanol from seaweeds. Bioengineered 2013; 4:224-35. [PMID: 23314751 DOI: 10.4161/bioe.23396] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Bioethanol has attracted attention as an alternative to petroleum-derived fuel. Seaweeds have been proposed as some of the most promising raw materials for bioethanol production because they have several advantages over lignocellulosic biomass. However, because seaweeds contain low contents of glucans, i.e., polysaccharides composed of glucose, the conversion of only the glucans from seaweed is not sufficient to produce high concentrations of ethanol. Therefore, it is also necessary to produce ethanol from other specific carbohydrate components of seaweeds, including sulfated polysaccharides, mannitol, alginate, agar and carrageenan. This review summarizes the current state of research on the production of ethanol from seaweed carbohydrates for which the conversion of carbohydrates to sugars is a key step and makes comparisons with the production of ethanol from lignocellulosic biomass. This review provides valuable information necessary for the production of high concentrations of ethanol from seaweeds.
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Affiliation(s)
- Mitsunori Yanagisawa
- Laboratory of Basic and Applied Molecular Biotechnology, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
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Geddes CC, Mullinnix MT, Nieves IU, Hoffman RW, Sagues WJ, York SW, Shanmugam KT, Erickson JE, Vermerris WE, Ingram LO. Seed train development for the fermentation of bagasse from sweet sorghum and sugarcane using a simplified fermentation process. BIORESOURCE TECHNOLOGY 2013; 128:716-724. [PMID: 23375156 DOI: 10.1016/j.biortech.2012.09.121] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2012] [Revised: 09/21/2012] [Accepted: 09/28/2012] [Indexed: 06/01/2023]
Abstract
A process was developed for seed culture expansion (3.6 million-fold) using 5% of the hemicellulose hydrolysate from dilute acid pretreatment as the sole organic nutrient and source of sugar. Hydrolysate used for seed growth was neutralized with ammonia and combined with 1.0mM sodium metabisulfite immediately before inoculation. This seed protocol was tested with phosphoric acid pretreated sugarcane and sweet sorghum bagasse using a simplified process with co-fermentation of fiber, pentoses, and hexoses in a single vessel (SScF). A 6h liquefaction (L) step improved mixing prior to inoculation. Fermentations (L+SScF process) were completed in 72 h with high yields (>80 gal/US ton). Ethanol titers for this L+SScF process ranged from 24 g/L to 32 g/L, and were limited by the bagasse concentration (10% dry matter).
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Affiliation(s)
- C C Geddes
- Dept Microbiology & Cell Science, Univ Florida, Box 110700, Gainesville, FL 32611, United States
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Wang J, Zhang Y, Chen Y, Lin M, Lin Z. Global regulator engineering significantly improvedEscherichia colitolerances toward inhibitors of lignocellulosic hydrolysates. Biotechnol Bioeng 2012; 109:3133-42. [DOI: 10.1002/bit.24574] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2012] [Revised: 04/06/2012] [Accepted: 05/30/2012] [Indexed: 01/09/2023]
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Lee S, Nam D, Jung JY, Oh MK, Sang BI, Mitchell RJ. Identification of Escherichia coli biomarkers responsive to various lignin-hydrolysate compounds. BIORESOURCE TECHNOLOGY 2012; 114:450-456. [PMID: 22445268 DOI: 10.1016/j.biortech.2012.02.085] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Revised: 02/16/2012] [Accepted: 02/17/2012] [Indexed: 05/31/2023]
Abstract
Aberrations in the growth and transcriptome of Escherichia coli str. BL21(DE3) were determined when exposed to varying concentrations of ferulic acid (0.25-1 g/L), an aromatic carboxylic acid identified within lignin-cellulose hydrolysate samples. The expression of several individual genes (aaeA, aaeB, inaA and marA) was significantly induced, i.e., more than 4-fold, and thus these genes and the heat shock response gene htpG were selected as biomarkers to monitor E. coli's responses to five additional hydrolysate-related compounds, including vanillic acid, coumaric acid, 4-hydroxybenzoic acid, ferulaldehyde and furfural. While all of the biomarkers showed dose-dependent responses to most of the compounds, expression of aaeA and aaeB showed the greatest induction (5-30-fold) for all compounds tested except furfural. Lastly, the marA, inaA and htpG genes all showed higher expression levels when the culture was exposed to spruce hydrolysate samples, demonstrating the potential use of these genes as biomarkers.
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Affiliation(s)
- Siseon Lee
- School of Nano-Bioscience and Chemical Engineering, Ulsan National Institute of Science and Technology, 100 Banyeon-ri, Eonyang-eup, Ulsan 689-805, Republic of Korea
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Complex physiology and compound stress responses during fermentation of alkali-pretreated corn stover hydrolysate by an Escherichia coli ethanologen. Appl Environ Microbiol 2012; 78:3442-57. [PMID: 22389370 DOI: 10.1128/aem.07329-11] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The physiology of ethanologenic Escherichia coli grown anaerobically in alkali-pretreated plant hydrolysates is complex and not well studied. To gain insight into how E. coli responds to such hydrolysates, we studied an E. coli K-12 ethanologen fermenting a hydrolysate prepared from corn stover pretreated by ammonia fiber expansion. Despite the high sugar content (∼6% glucose, 3% xylose) and relatively low toxicity of this hydrolysate, E. coli ceased growth long before glucose was depleted. Nevertheless, the cells remained metabolically active and continued conversion of glucose to ethanol until all glucose was consumed. Gene expression profiling revealed complex and changing patterns of metabolic physiology and cellular stress responses during an exponential growth phase, a transition phase, and the glycolytically active stationary phase. During the exponential and transition phases, high cell maintenance and stress response costs were mitigated, in part, by free amino acids available in the hydrolysate. However, after the majority of amino acids were depleted, the cells entered stationary phase, and ATP derived from glucose fermentation was consumed entirely by the demands of cell maintenance in the hydrolysate. Comparative gene expression profiling and metabolic modeling of the ethanologen suggested that the high energetic cost of mitigating osmotic, lignotoxin, and ethanol stress collectively limits growth, sugar utilization rates, and ethanol yields in alkali-pretreated lignocellulosic hydrolysates.
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48
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Increased furan tolerance in Escherichia coli due to a cryptic ucpA gene. Appl Environ Microbiol 2012; 78:2452-5. [PMID: 22267665 DOI: 10.1128/aem.07783-11] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Expression arrays were used to identify 4 putative oxidoreductases that were upregulated (>3-fold) by furfural (15 mM, 15 min). Plasmid expression of one (ucpA) increased furan tolerance in ethanologenic strain LY180 and wild-type strain W. Deleting ucpA decreased furfural tolerance. Although the mechanism remains unknown, the cryptic ucpA gene is now associated with a phenotype: furan resistance.
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49
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Yanagisawa M, Nakamura K, Ariga O, Nakasaki K. Production of high concentrations of bioethanol from seaweeds that contain easily hydrolyzable polysaccharides. Process Biochem 2011. [DOI: 10.1016/j.procbio.2011.08.001] [Citation(s) in RCA: 124] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Enzyme-assisted extraction of bioactives from plants. Trends Biotechnol 2011; 30:37-44. [PMID: 21816495 DOI: 10.1016/j.tibtech.2011.06.014] [Citation(s) in RCA: 350] [Impact Index Per Article: 26.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2010] [Revised: 06/01/2011] [Accepted: 06/27/2011] [Indexed: 11/22/2022]
Abstract
Demand for new and novel natural compounds has intensified the development of plant-derived compounds known as bioactives that either promote health or are toxic when ingested. Enhanced release of these bioactives from plant cells by cell disruption and extraction through the cell wall can be optimized using enzyme preparations either alone or in mixtures. However, the biotechnological application of enzymes is not currently exploited to its maximum potential within the food industry. Here, we discuss the use of environmentally friendly enzyme-assisted extraction of bioactive compounds from plant sources, particularly for food and nutraceutical purposes. In particular, we discuss an enzyme-assisted extraction of stevioside from Stevia rebaudiana, as an example of a process of potential value to the food industry.
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