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Geng B, Liu S, Chen Y, Wu Y, Wang Y, Zhou X, Li H, Li M, Yang S. A plasmid-free Zymomonas mobilis mutant strain reducing reactive oxygen species for efficient bioethanol production using industrial effluent of xylose mother liquor. Front Bioeng Biotechnol 2022; 10:1110513. [PMID: 36619397 PMCID: PMC9816438 DOI: 10.3389/fbioe.2022.1110513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Accepted: 12/12/2022] [Indexed: 12/24/2022] Open
Abstract
Genome minimization is an effective way for industrial chassis development. In this study, Zymomonas mobilis ZMNP, a plasmid-free mutant strain of Z. mobilis ZM4 with four native plasmids deleted, was constructed using native type I-F CRISPR-Cas system. Cell growth of ZMNP under different temperatures and industrial effluent of xylose mother liquor were examined to investigate the impact of native plasmid removal. Despite ZMNP grew similarly as ZM4 under different temperatures, ZMNP had better xylose mother liquor utilization than ZM4. In addition, genomic, transcriptomic, and proteomic analyses were applied to unravel the molecular changes between ZM4 and ZMNP. Whole-genome resequencing result indicated that an S267P mutation in the C-terminal of OxyR, a peroxide-sensing transcriptional regulator, probably alters the transcription initiation of antioxidant genes for stress responses. Transcriptomic and proteomic studies illustrated that the reason that ZMNP utilized the toxic xylose mother liquor better than ZM4 was probably due to the upregulation of genes in ZMNP involving in stress responses as well as cysteine biosynthesis to accelerate the intracellular ROS detoxification and nucleic acid damage repair. This was further confirmed by lower ROS levels in ZMNP compared to ZM4 in different media supplemented with furfural or ethanol. The upregulation of stress response genes due to the OxyR mutation to accelerate ROS detoxification and DNA/RNA repair not only illustrates the underlying mechanism of the robustness of ZMNP in the toxic xylose mother liquor, but also provides an idea for the rational design of synthetic inhibitor-tolerant microorganisms for economic lignocellulosic biochemical production.
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Affiliation(s)
- Binan Geng
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, School of Life Sciences, Hubei University, Wuhan, China
| | - Shuyi Liu
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, School of Life Sciences, Hubei University, Wuhan, China
| | - Yunhao Chen
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, School of Life Sciences, Hubei University, Wuhan, China
| | - Yalun Wu
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, School of Life Sciences, Hubei University, Wuhan, China
| | - Yi Wang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, School of Life Sciences, Hubei University, Wuhan, China
| | - Xuan Zhou
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, School of Life Sciences, Hubei University, Wuhan, China
| | - Han Li
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, School of Life Sciences, Hubei University, Wuhan, China
| | - Mian Li
- Zhejiang Huakang Pharmaceutical Co., Ltd., Quzhou, Zhejiang, China
| | - Shihui Yang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, School of Life Sciences, Hubei University, Wuhan, China,*Correspondence: Shihui Yang,
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2
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Yan X, Wang X, Yang Y, Wang Z, Zhang H, Li Y, He Q, Li M, Yang S. Cysteine supplementation enhanced inhibitor tolerance of Zymomonas mobilis for economic lignocellulosic bioethanol production. BIORESOURCE TECHNOLOGY 2022; 349:126878. [PMID: 35189331 DOI: 10.1016/j.biortech.2022.126878] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 02/15/2022] [Accepted: 02/16/2022] [Indexed: 05/26/2023]
Abstract
Inhibitors in lignocellulosic hydrolysates are toxic to Zymomonas mobilis and reduce its bioethanol production. This study revealed cysteine supplementation enhanced furfural tolerance in Z. mobilis with a 2-fold biomass increase. Transcriptomic study illustrated that cysteine biosynthesis pathway was down-regulated while cysteine catabolism was up-regulated with cysteine supplementation. Mutants for genes involved in cysteine metabolism were constructed, and metabolites in cysteine metabolic pathway including methionine, glutathione, NaHS, glutamate, and pyruvate were supplemented into media. Cysteine supplementation boosted glutathione synthesis or H2S release effectively in Z. mobilis leading to the reduced accumulation of reactive oxygen species (ROS) induced by furfural, while pyruvate and glutamate produced in the H2S generation pathway promoted cell growth by serving as the carbon or nitrogen source. Finally, cysteine supplementation was confirmed to enhance Z. mobilis tolerance against ethanol, acetate, and corncob hydrolysate with an enhanced ethanol productivity from 0.38 to 0.55 g-1∙L-1∙h-1.
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Affiliation(s)
- Xiongying Yan
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, and School of Life Sciences, Hubei University, Wuhan 430062, China
| | - Xia Wang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, and School of Life Sciences, Hubei University, Wuhan 430062, China
| | - Yongfu Yang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, and School of Life Sciences, Hubei University, Wuhan 430062, China
| | - Zhen Wang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, and School of Life Sciences, Hubei University, Wuhan 430062, China
| | - Haoyu Zhang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, and School of Life Sciences, Hubei University, Wuhan 430062, China
| | - Yang Li
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, and School of Life Sciences, Hubei University, Wuhan 430062, China
| | - Qiaoning He
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, and School of Life Sciences, Hubei University, Wuhan 430062, China
| | - Mian Li
- Zhejiang Huakang Pharmaceutical Co., Ltd., Kaihua County, Zhejiang, China
| | - Shihui Yang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, and School of Life Sciences, Hubei University, Wuhan 430062, China.
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3
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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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4
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Cheng HH, Whang LM. Resource recovery from lignocellulosic wastes via biological technologies: Advancements and prospects. BIORESOURCE TECHNOLOGY 2022; 343:126097. [PMID: 34626758 DOI: 10.1016/j.biortech.2021.126097] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 10/04/2021] [Accepted: 10/05/2021] [Indexed: 06/13/2023]
Abstract
Lignocellulosic wastes were recently considered as biomass resources, however, its conversion to valuable products is still immature although researchers have put lots of effort into this issue. This article reviews the key challenges of the biorefinery utilizing lignocellulosic materials and recent developments to conquer those obstacles. Available biological techniques and processes, from the pretreatments of cellulosic materials to the valorization processes, were emphasized. Biological pretreatments, including hydrolysis using microbial consortia, fungi, enzymes, engineered bacterial/fungal strains, and co-culture systems, could enhance the release of reducing sugar. Resources recovery, including biogases, ethanol, butanol, PHA, etc., from lignocellulosic materials were also discussed, while the influences of composition of lignocellulosic materials and pretreatment options, applications of co-culture system, and integrated treatments with other wastes, were described. In the review, co-culture system and metabolic engineering are emphasized as the promising biological technologies, while perspectives are provided for their future developments.
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Affiliation(s)
- Hai-Hsuan Cheng
- Department of Environmental Engineering, National Cheng Kung University, No. 1, University Road, Tainan 701, Taiwan
| | - Liang-Ming Whang
- Department of Environmental Engineering, National Cheng Kung University, No. 1, University Road, Tainan 701, Taiwan; Sustainable Environment Research Laboratory (SERL), National Cheng Kung University, No. 1, University Road, Tainan 701, Taiwan.
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5
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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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Shi A, Yomano LP, York SW, Zheng H, Shanmugam KT, Ingram LO. Chromosomal mutations in Escherichia coli that improve tolerance to nonvolatile side-products from dilute acid treatment of sugarcane bagasse. Biotechnol Bioeng 2019; 117:85-95. [PMID: 31612993 DOI: 10.1002/bit.27189] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 09/16/2019] [Accepted: 10/10/2019] [Indexed: 01/03/2023]
Abstract
Lignocellulosic biomass provides attractive nonfood carbohydrates for the production of ethanol, and dilute acid pretreatment is a biomass-independent process for access to these carbohydrates. However, this pretreatment also releases volatile and nonvolatile inhibitors of fermenting microorganisms. To identify unique gene products contributing to sensitivity/tolerance to nonvolatile inhibitors, ethanologenic Escherichia coli strain LY180 was adapted for growth in vacuum-treated sugarcane bagasse acid hydrolysate (VBHz) lacking furfural and other volatile inhibitors. A mutant, strain AQ15, obtained after approximately 500 generations of growth in VBHz, grew and fermented the sugars in a medium with 50% VBHz. Comparative genome sequence analysis of strains AQ15 and LY180 revealed 95 mutations in strain AQ15. Six of these mutations were also found in strain SL112, an independent inhibitor-tolerant derivative of strain LY180. Among these six mutations, null mutations in mdh and bacA were identified as contributing factors to VBHz tolerance in strain AQ15, based on the genetic and physiological analysis. The deletion of either gene in strain LY180 increased tolerance to VBHz from approximately 30-50% (vol/vol). Considering the location and physiological role of the two enzymes in the cell, it is likely that the two enzymes contribute to the VBHz sensitivity of ethanologenic E. coli by different mechanisms.
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Affiliation(s)
- Aiqin Shi
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida.,Department of Biochemistry and Molecular Biology, Penn State College of Medicine, Hershey, Pennsylvania
| | - Lorraine P Yomano
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida
| | - Sean W York
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida
| | - Huabao Zheng
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida.,Key Laboratory of Soil Contamination Bioremediation of Zhejiang Province, College of Environmental and Resource Sciences, Zhejiang A & F University, Hangzhou, China
| | - Keelnatham T Shanmugam
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida
| | - Lonnie O Ingram
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida
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7
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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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8
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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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9
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Skiba EA, Budaeva VV, Baibakova OV, Zolotukhin VN, Sakovich GV. Dilute nitric-acid pretreatment of oat hulls for ethanol production. Biochem Eng J 2017. [DOI: 10.1016/j.bej.2016.09.003] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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10
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Shi A, Zheng H, Yomano LP, York SW, Shanmugam KT, Ingram LO. Plasmidic Expression of nemA and yafC* Increased Resistance of Ethanologenic Escherichia coli LY180 to Nonvolatile Side Products from Dilute Acid Treatment of Sugarcane Bagasse and Artificial Hydrolysate. Appl Environ Microbiol 2016; 82:2137-2145. [PMID: 26826228 PMCID: PMC4807516 DOI: 10.1128/aem.03488-15] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Accepted: 01/24/2016] [Indexed: 11/20/2022] Open
Abstract
Hydrolysate-resistant Escherichia coli SL100 was previously isolated from ethanologenic LY180 after sequential transfers in AM1 medium containing a dilute acid hydrolysate of sugarcane bagasse and was used as a source of resistance genes. Many genes that affect tolerance to furfural, the most abundant inhibitor, have been described previously. To identify genes associated with inhibitors other than furfural, plasmid clones were selected in an artificial hydrolysate that had been treated with a vacuum to remove furfural. Two new resistance genes were discovered from Sau3A1 libraries of SL100 genomic DNA: nemA (N-ethylmaleimide reductase) and a putative regulatory gene containing a mutation in the coding region, yafC*. The presence of these mutations in SL100 was confirmed by sequencing. A single mutation was found in the upstream regulatory region of nemR (nemRA operon) in SL100. This mutation increased nemA activity 20-fold over that of the parent organism (LY180) in AM1 medium without hydrolysate and increased nemA mRNA levels >200-fold. Addition of hydrolysates induced nemA expression (mRNA and activity), in agreement with transcriptional control. NemA activity was stable in cell extracts (9 h, 37°C), eliminating a role for proteinase in regulation. LY180 with a plasmid expressing nemA or yafC* was more resistant to a vacuum-treated sugarcane bagasse hydrolysate and to a vacuum-treated artificial hydrolysate than LY180 with an empty-vector control. Neither gene affected furfural tolerance. The vacuum-treated hydrolysates inhibited the reduction of N-ethylmaleimide by NemA while also serving as substrates. Expression of the nemA or yafC* plasmid in LY180 doubled the rate of ethanol production from the vacuum-treated sugarcane bagasse hydrolysate.
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Affiliation(s)
- Aiqin Shi
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, USA
| | - Huabao Zheng
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, USA
| | - Lorraine P Yomano
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, USA
| | - Sean W York
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, USA
| | - Keelnatham T Shanmugam
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, USA
| | - Lonnie O Ingram
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, USA
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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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12
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Sawisit A, Jantama K, Zheng H, Yomano LP, York SW, Shanmugam KT, Ingram LO. Mutation in galP improved fermentation of mixed sugars to succinate using engineered Escherichia coli AS1600a and AM1 mineral salts medium. BIORESOURCE TECHNOLOGY 2015; 193:433-441. [PMID: 26159300 DOI: 10.1016/j.biortech.2015.06.108] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Revised: 06/18/2015] [Accepted: 06/19/2015] [Indexed: 06/04/2023]
Abstract
Escherichia coli KJ122 was engineered to produce succinate from glucose using the wild type GalP for glucose uptake instead of the native phosphotransferase system (ptsI mutation). This strain now ferments 10% xylose poorly. Mutants were selected by serial transfers in AM1 mineral salts medium with 10% xylose. Clones from this population all exhibited a similar improvement, co-fermentation of an equal mixture of xylose and glucose. One of these, AS1600a, produced 84.26 ± 1.37 g/L succinate, equivalent to that produced by the parent (KJ122) from 10% glucose (85.46 ± 1.78 g/L). AS1600a was sequenced and found to contain a mutation in galactose permease (GalP, G236D). This mutation was shown to be responsible for the improvement in fermentation using KJΔgalP as the host and expression vectors with native galP and with mutant galP(∗). Strain AS1600a and KJΔgalP(pLOI5746; galP(∗)) also co-fermented a mixture of glucose, xylose, arabinose, and galactose in sugarcane bagasse hydrolysate using mineral salts medium.
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Affiliation(s)
- Apichai Sawisit
- Metabolic Engineering Research Unit, School of Biotechnology, Institute of Agricultural Technology, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand
| | - Kaemwich Jantama
- Metabolic Engineering Research Unit, School of Biotechnology, Institute of Agricultural Technology, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand
| | - Huabao Zheng
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL 32611, USA
| | - Lorraine P Yomano
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL 32611, USA
| | - Sean W York
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL 32611, USA
| | - Keelnatham T Shanmugam
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL 32611, USA
| | - Lonnie O Ingram
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL 32611, USA.
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Geddes R, Shanmugam KT, Ingram LO. Combining treatments to improve the fermentation of sugarcane bagasse hydrolysates by ethanologenic Escherichia coli LY180. BIORESOURCE TECHNOLOGY 2015; 189:15-22. [PMID: 25864026 DOI: 10.1016/j.biortech.2015.03.141] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Revised: 03/27/2015] [Accepted: 03/29/2015] [Indexed: 06/04/2023]
Abstract
Inhibitory side products from dilute acid pretreatment is a major challenge for conversion of lignocellulose into ethanol. Six strategies to detoxify sugarcane hydrolysates were investigated alone, and in combinations (vacuum evaporation of volatiles, high pH treatment with ammonia, laccase, bisulfite, microaeration, and inoculum size). High pH was the most beneficial single treatment, increasing the minimum inhibitory concentration (measured by ethanol production) from 15% (control) to 70% hydrolysate. Combining treatments provided incremental improvements, consistent with different modes of action and multiple inhibitory compounds. Screening toxicity using tube cultures proved to be an excellent predictor of relative performance in pH-controlled fermenters. A combination of treatments (vacuum evaporation, laccase, high pH, bisulfite, microaeration) completely eliminated all inhibitory activity present in hydrolysate. With this combination, fermentation of hemicellulose sugars (90% hydrolysate) to ethanol was complete within 48 h, identical to the fermentation of laboratory xylose (50 g/L) in AM1 mineral salts medium (without hydrolysate).
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Affiliation(s)
- Ryan Geddes
- Department of Microbiology & Cell Science, University of Florida, Box 110700, Gainesville, FL 32611, USA.
| | - Keelnatham T Shanmugam
- Department of Microbiology & Cell Science, University of Florida, Box 110700, Gainesville, FL 32611, USA.
| | - Lonnie O Ingram
- Department of Microbiology & Cell Science, University of Florida, Box 110700, Gainesville, FL 32611, USA.
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14
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Skerker JM, Leon D, Price MN, Mar JS, Tarjan DR, Wetmore KM, Deutschbauer AM, Baumohl JK, Bauer S, Ibáñez AB, Mitchell VD, Wu CH, Hu P, Hazen T, Arkin AP. Dissecting a complex chemical stress: chemogenomic profiling of plant hydrolysates. Mol Syst Biol 2013; 9:674. [PMID: 23774757 PMCID: PMC3964314 DOI: 10.1038/msb.2013.30] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Accepted: 05/12/2013] [Indexed: 11/09/2022] Open
Abstract
Complex chemical stress arises during the production of biofuels. Large-scale mutant fitness profiling was used to identify bacterial and yeast tolerance genes and to model fitness in a complex hydrolysate mixture. The resulting model can be used to engineer more tolerant strains. ![]()
Genome-wide fitness profiling was used to identify plant hydrolysate tolerance genes in Zymomonas mobilis and Saccharomyces cerevisiae. We modeled fitness in hydrolysate as a mixture of fitness in its components. Outliers in our model led to the identification of a previously unknown component of hydrolysate. Overexpression of a Z. mobilis tolerance gene of unknown function improved ethanol productivity in plant hydrolysate.
The efficient production of biofuels from cellulosic feedstocks will require the efficient fermentation of the sugars in hydrolyzed plant material. Unfortunately, plant hydrolysates also contain many compounds that inhibit microbial growth and fermentation. We used DNA-barcoded mutant libraries to identify genes that are important for hydrolysate tolerance in both Zymomonas mobilis (44 genes) and Saccharomyces cerevisiae (99 genes). Overexpression of a Z. mobilis tolerance gene of unknown function (ZMO1875) improved its specific ethanol productivity 2.4-fold in the presence of miscanthus hydrolysate. However, a mixture of 37 hydrolysate-derived inhibitors was not sufficient to explain the fitness profile of plant hydrolysate. To deconstruct the fitness profile of hydrolysate, we profiled the 37 inhibitors against a library of Z. mobilis mutants and we modeled fitness in hydrolysate as a mixture of fitness in its components. By examining outliers in this model, we identified methylglyoxal as a previously unknown component of hydrolysate. Our work provides a general strategy to dissect how microbes respond to a complex chemical stress and should enable further engineering of hydrolysate tolerance.
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Affiliation(s)
- Jeffrey M Skerker
- Energy Biosciences Institute, University of California, Berkeley, CA, USA
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Cavka A, Jönsson LJ. Detoxification of lignocellulosic hydrolysates using sodium borohydride. BIORESOURCE TECHNOLOGY 2013; 136:368-76. [PMID: 23567704 DOI: 10.1016/j.biortech.2013.03.014] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2013] [Revised: 03/01/2013] [Accepted: 03/04/2013] [Indexed: 05/12/2023]
Abstract
Addition of sodium borohydride to a lignocellulose hydrolysate of Norway spruce affected the fermentability when cellulosic ethanol was produced using Saccharomyces cerevisiae. Treatment of the hydrolysate with borohydride improved the ethanol yield on consumed sugar from 0.09 to 0.31 g/g, the balanced ethanol yield from 0.02 to 0.30 g/g, and the ethanol productivity from 0.05 to 0.57 g/(L×h). Treatment of a sugarcane bagasse hydrolysate gave similar results, and the experiments indicate that sodium borohydride is suitable for chemical in situ detoxification. The model inhibitors coniferyl aldehyde, p-benzoquinone, 2,6-dimethoxybenzoquinone, and furfural were efficiently reduced by treatment with sodium borohydride, even under mild reaction conditions (20 °C and pH 6.0). While addition of sodium dithionite to pretreatment liquid from spruce improved enzymatic hydrolysis of cellulose, addition of sodium borohydride did not. This result indicates that the strong hydrophilicity resulting from sulfonation of inhibitors by dithionite treatment was particularly important for alleviating enzyme inhibition.
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Affiliation(s)
- Adnan Cavka
- Department of Chemistry, Umeå University, SE-901 87 Umeå, Sweden
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Choh LC, Ong GH, Vellasamy KM, Kalaiselvam K, Kang WT, Al-Maleki AR, Mariappan V, Vadivelu J. Burkholderia vaccines: are we moving forward? Front Cell Infect Microbiol 2013; 3:5. [PMID: 23386999 PMCID: PMC3564208 DOI: 10.3389/fcimb.2013.00005] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2012] [Accepted: 01/20/2013] [Indexed: 11/29/2022] Open
Abstract
The genus Burkholderia consists of diverse species which includes both "friends" and "foes." Some of the "friendly" Burkholderia spp. are extensively used in the biotechnological and agricultural industry for bioremediation and biocontrol. However, several members of the genus including B. pseudomallei, B. mallei, and B. cepacia, are known to cause fatal disease in both humans and animals. B. pseudomallei and B. mallei are the causative agents of melioidosis and glanders, respectively, while B. cepacia infection is lethal to cystic fibrosis (CF) patients. Due to the high rate of infectivity and intrinsic resistance to many commonly used antibiotics, together with high mortality rate, B. mallei and B. pseudomallei are considered to be potential biological warfare agents. Treatments of the infections caused by these bacteria are often unsuccessful with frequent relapse of the infection. Thus, we are at a crucial stage of the need for Burkholderia vaccines. Although the search for a prophylactic therapy candidate continues, to date development of vaccines has not advanced beyond research to human clinical trials. In this article, we review the current research on development of safe vaccines with high efficacy against B. pseudomallei, B. mallei, and B. cepacia. It can be concluded that further research will enable elucidation of the potential benefits and risks of Burkholderia vaccines.
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Affiliation(s)
| | | | | | | | | | | | | | - Jamuna Vadivelu
- Department of Medical Microbiology, Faculty of Medicine, University of MalayaKuala Lumpur, Malaysia
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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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Nieves IU, Geddes CC, Mullinnix MT, Hoffman RW, Tong Z, Castro E, Shanmugam KT, Ingram LO. Injection of air into the headspace improves fermentation of phosphoric acid pretreated sugarcane bagasse by Escherichia coli MM170. BIORESOURCE TECHNOLOGY 2011; 102:6959-65. [PMID: 21531547 DOI: 10.1016/j.biortech.2011.04.036] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2011] [Revised: 04/08/2011] [Accepted: 04/11/2011] [Indexed: 05/23/2023]
Abstract
Microaeration (injecting air into the headspace) improved the fermentation of hemicellulose hydrolysates obtained from the phosphoric acid pretreatment of sugarcane bagasse at 170°C for 10 min. In addition, with 10% slurries of phosphoric acid pretreated bagasse (180°C, 10 min), air injection into the headspace promoted xylose utilization and increased ethanol yields from 0.16 to 0.20 g ethanol/g bagasse dry weight using a liquefaction plus simultaneous saccharification and co-fermentation process (L+SScF). This process was scaled up to 80 L using slurries of acid pretreated bagasse (96 h incubation; 0.6L of air/min into the headspace) with ethanol yields of 312-347 L (82-92 gal) per tone (dry matter), corresponding to 0.25 and 0.27 g/g bagasse (dry weight). Injection of small amounts of air into the headspace may provide a convenient alternative to subsurface sparging that avoids problems of foaming, sparger hygiene, flotation of particulates, and phase separation.
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Affiliation(s)
- I U Nieves
- Department of Microbiology & Cell Science, University of Florida, Box 110700, Gainesville, FL 32611, USA.
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Geddes CC, Nieves IU, Ingram LO. Advances in ethanol production. Curr Opin Biotechnol 2011; 22:312-9. [DOI: 10.1016/j.copbio.2011.04.012] [Citation(s) in RCA: 184] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2011] [Accepted: 04/18/2011] [Indexed: 12/23/2022]
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