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Liu W, Li H, Guo D, Ni Y, Zhang X, Shi J, Koffas MAG, Xu Z. Engineering of redox partners and cofactor NADPH supply of CYP68JX for efficient steroid two-step ordered selective hydroxylation activity. J Steroid Biochem Mol Biol 2024; 238:106452. [PMID: 38160767 DOI: 10.1016/j.jsbmb.2023.106452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 12/25/2023] [Accepted: 12/27/2023] [Indexed: 01/03/2024]
Abstract
CYP68JX, a P450 hydroxylase, derived from Colletotrichum lini ST-1 is capable of biotransforming dehydroepiandrosterone (DHEA) to 3β,7α,15α-trihydroxy-5-androstene-17-one (7α,15α-diOH-DHEA). Redox partners and cofactor supply are important factors affecting the catalytic activity of CYP68JX. In this study, the heterologous expression of CYP68JX in Saccharomyces cerevisiae BY4741 was realized resulting in a 17.1% target product yield. In order to increase the catalytic efficiency of CYP68JX in S. cerevisiae BY4741, a complete cytochrome P450 redox system was constructed. Through the combination of CYP68JX and heterologous CPRs, the yield of the target product 7α,15α-diOH-DHEA in CYP68JX recombinant system was increased to 37.8%. Furthermore, by adding NADPH coenzyme precursor tryptophan of 40 mmol/L and co-substrate fructose of 20 g/L during the conversion process, the catalytic efficiency of CYP68JX was further improved, the target product yield reached 57.9% which was 3.39-fold higher than initial yield. Overall, this study provides a reference for improving the catalytic activity of P450s.
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Affiliation(s)
- Wei Liu
- School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Hui Li
- School of Life Sciences and Health Engineering, Jiangnan University, Wuxi 214122, China.
| | - Dongxin Guo
- School of Life Sciences and Health Engineering, Jiangnan University, Wuxi 214122, China
| | - Yu Ni
- School of Life Sciences and Health Engineering, Jiangnan University, Wuxi 214122, China
| | - Xiaomei Zhang
- School of Life Sciences and Health Engineering, Jiangnan University, Wuxi 214122, China
| | - Jinsong Shi
- School of Life Sciences and Health Engineering, Jiangnan University, Wuxi 214122, China
| | - Mattheos A G Koffas
- Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY 12180, United States.
| | - Zhenghong Xu
- National Engineering Research Center of Cereal Fermentation and Food Biomanufacturing, Jiangnan University, Wuxi 214122, China; Jiangsu Provincial Research Center for Bioactive Product Processing Technology, Jiangnan University, Wuxi 214122, China
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2
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Zou S, Lu J, Zhang B, Li X, Jiang Z, Xue Y, Zheng Y. A combination fermentation strategy for simultaneously increasing cellular NADP(H) level, biomass, and enzymatic activity of glufosinate dehydrogenase in Escherichia coli. Bioprocess Biosyst Eng 2023; 46:867-878. [PMID: 37022468 DOI: 10.1007/s00449-023-02871-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Accepted: 03/26/2023] [Indexed: 04/07/2023]
Abstract
Oxidoreductase is one of the most important biocatalysts for the synthesis of various chiral compounds. However, their whole-cell activity is frequently affected by an insufficient supply of expensive nicotinamide cofactors. This study aimed to overcome such shortcomings by developing a combination fermentation strategy for simultaneously increasing intracellular NADP(H) level, biomass, and glufosinate dehydrogenase activity in E. coli. The results showed that the feeding mode of NAD(H) synthesis precursor and lactose inducer had essential effects on the accumulation level of intracellular NADPH. Adding 40 mg L-1 of L-aspartic acid to the medium increased the intracellular NADP(H) concentration by 36.3%. Under the pH-stat feeding mode and adding 0.4 g L-1 h-1 lactose, the NADP(H) concentration, biomass, and GluDH activity in the 5-L fermenter reached 445.7 μmol L-1, 21.7 gDCW L-1, and 8569.3 U L-1, respectively. As far as we know, this is the highest reported activity of GluDH in the fermentation broth. Finally, the 5000-L fermenter was successfully scaled up to use this fermentation approach. The combination fermentation strategy might serve as a useful approach for the high-activity fermentation of other NADPH-dependent oxidoreductases.
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Affiliation(s)
- Shuping Zou
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, China
- Engineering Research Center of Bioconversion and Biopurification of Ministry of Education, Zhejiang University of Technology, Hangzhou, 310014, China
| | - Jiawei Lu
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, China
- Engineering Research Center of Bioconversion and Biopurification of Ministry of Education, Zhejiang University of Technology, Hangzhou, 310014, China
| | - Bing Zhang
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, China
- Engineering Research Center of Bioconversion and Biopurification of Ministry of Education, Zhejiang University of Technology, Hangzhou, 310014, China
| | - Xia Li
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, China
- Engineering Research Center of Bioconversion and Biopurification of Ministry of Education, Zhejiang University of Technology, Hangzhou, 310014, China
| | - Zhentao Jiang
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, China
- Engineering Research Center of Bioconversion and Biopurification of Ministry of Education, Zhejiang University of Technology, Hangzhou, 310014, China
| | - Yaping Xue
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, China.
- Engineering Research Center of Bioconversion and Biopurification of Ministry of Education, Zhejiang University of Technology, Hangzhou, 310014, China.
| | - Yuguo Zheng
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, China
- Engineering Research Center of Bioconversion and Biopurification of Ministry of Education, Zhejiang University of Technology, Hangzhou, 310014, China
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Metabolic engineering of Escherichia coli for improved D-pantothenic acid biosynthesis by enhancing NADPH availability. Biochem Eng J 2022. [DOI: 10.1016/j.bej.2022.108603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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4
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Paramasivan K, Abdulla A, Gupta N, Mutturi S. In silico target-based strain engineering of Saccharomyces cerevisiae for terpene precursor improvement. Integr Biol (Camb) 2022; 14:25-36. [DOI: 10.1093/intbio/zyac003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 02/22/2022] [Accepted: 02/25/2022] [Indexed: 11/13/2022]
Abstract
Abstract
Systems-based metabolic engineering enables cells to enhance product formation by predicting gene knockout and overexpression targets using modeling tools. FOCuS, a novel metaheuristic tool, was used to predict flux improvement targets in terpenoid pathway using the genome-scale model of Saccharomyces cerevisiae, iMM904. Some of the key knockout target predicted includes LYS1, GAP1, AAT1, AAT2, TH17, KGD-m, MET14, PDC1 and ACO1. It was also observed that the knockout reactions belonged either to fatty acid biosynthesis, amino acid synthesis pathways or nucleotide biosynthesis pathways. Similarly, overexpression targets such as PFK1, FBA1, ZWF1, TDH1, PYC1, ALD6, TPI1, PDX1 and ENO1 were established using three different existing gene amplification algorithms. Most of the overexpression targets belonged to glycolytic and pentose phosphate pathways. Each of these targets had plausible role for improving flux toward sterol pathway and were seemingly not artifacts. Moreover, an in vitro study as validation was carried with overexpression of ALD6 and TPI1. It was found that there was an increase in squalene synthesis by 2.23- and 4.24- folds, respectively, when compared with control. In general, the rationale for predicting these in silico targets was attributed to either increasing the acetyl-CoA precursor pool or regeneration of NADPH, which increase the sterol pathway flux.
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Affiliation(s)
- Kalaivani Paramasivan
- Microbiology and Fermentation Technology Department, CSIR-Central Food Technological Research Institute, Mysuru, India
- Academy of Scientific and Innovative Research, Ghaziabad, Uttar Pradesh, India
- Department of Bioengineering, University of Illinois, Urbana-Champaign, IL, USA
| | - Aneesha Abdulla
- Microbiology and Fermentation Technology Department, CSIR-Central Food Technological Research Institute, Mysuru, India
- Academy of Scientific and Innovative Research, Ghaziabad, Uttar Pradesh, India
| | - Nabarupa Gupta
- Microbiology and Fermentation Technology Department, CSIR-Central Food Technological Research Institute, Mysuru, India
| | - Sarma Mutturi
- Microbiology and Fermentation Technology Department, CSIR-Central Food Technological Research Institute, Mysuru, India
- Academy of Scientific and Innovative Research, Ghaziabad, Uttar Pradesh, India
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Paramasivan K, Kumar HN P, Mutturi S. Systems-based Saccharomyces cerevisiae strain design for improved squalene synthesis. Biochem Eng J 2019. [DOI: 10.1016/j.bej.2019.04.025] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Li T, Zhang C, Yang KL, He J. Unique genetic cassettes in a Thermoanaerobacterium contribute to simultaneous conversion of cellulose and monosugars into butanol. SCIENCE ADVANCES 2018; 4:e1701475. [PMID: 29740597 PMCID: PMC5938282 DOI: 10.1126/sciadv.1701475] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Accepted: 02/07/2018] [Indexed: 05/25/2023]
Abstract
The demand for cellulosic biofuels is on the rise because of the anticipation for sustainable energy and less greenhouse gas emissions in the future. However, production of cellulosic biofuels, especially cellulosic butanol, has been hampered by the lack of potent microbes that are capable of converting cellulosic biomass into biofuels. We report a wild-type Thermoanaerobacterium thermosaccharolyticum strain TG57, which is capable of using microcrystalline cellulose directly to produce butanol (1.93 g/liter) as the only final product (without any acetone or ethanol produced), comparable to that of engineered microbes thus far. Strain TG57 exhibits significant advances including unique genes responsible for a new butyrate synthesis pathway, no carbon catabolite repression, and the absence of genes responsible for acetone synthesis (which is observed as the main by-product in most Clostridium strains known today). Furthermore, the use of glucose analog 2-deoxyglucose posed a selection pressure to facilitate isolation of strain TG57 with deletion/silencing of carbon catabolite repressor genes-the ccr and xylR genes-and thus is able to simultaneously ferment glucose, xylose, and arabinose to produce butanol (7.33 g/liter) as the sole solvent. Combined analysis of genomic and transcriptomic data revealed unusual aspects of genome organization, numerous determinants for unique bioconversions, regulation of central metabolic pathways, and distinct transcriptomic profiles. This study provides a genome-level understanding of how cellulose is metabolized by T. thermosaccharolyticum and sheds light on the potential of competitive and sustainable biofuel production.
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Affiliation(s)
- Tinggang Li
- Department of Civil and Environmental Engineering, National University of Singapore, Singapore 117576
| | - Chen Zhang
- Department of Civil and Environmental Engineering, National University of Singapore, Singapore 117576
| | - Kun-Lin Yang
- Department of Chemical and Biomolecular Engineering, National University of Singapore, Singapore 117576
| | - Jianzhong He
- Department of Civil and Environmental Engineering, National University of Singapore, Singapore 117576
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7
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Wang C, Xin F, Kong X, Zhao J, Dong W, Zhang W, Ma J, Wu H, Jiang M. Enhanced isopropanol-butanol-ethanol mixture production through manipulation of intracellular NAD(P)H level in the recombinant Clostridium acetobutylicum XY16. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:12. [PMID: 29410706 PMCID: PMC5782381 DOI: 10.1186/s13068-018-1024-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Accepted: 01/13/2018] [Indexed: 05/17/2023]
Abstract
BACKGROUND The formation of by-products, mainly acetone in acetone-butanol-ethanol (ABE) fermentation, significantly affects the solvent yield and downstream separation process. In this study, we genetically engineered Clostridium acetobutylicum XY16 isolated by our lab to eliminate acetone production and altered ABE to isopropanol-butanol-ethanol (IBE). Meanwhile, process optimization under pH control strategies and supplementation of calcium carbonate were adopted to investigate the interaction between the reducing force of the metabolic networks and IBE production. RESULTS After successful introduction of secondary alcohol dehydrogenase into C. acetobutylicum XY16, the recombinant XY16 harboring pSADH could completely eliminate acetone production and convert it into isopropanol, indicating great potential for large-scale production of IBE mixtures. Especially, pH could significantly improve final solvent titer through regulation of NADH and NADPH levels in vivo. Under the optimal pH level of 4.8, the total IBE production was significantly increased from 3.88 to 16.09 g/L with final 9.97, 4.98 and 1.14 g/L of butanol, isopropanol, and ethanol. Meanwhile, NADH and NADPH levels were maintained at optimal levels for IBE formation compared to the control one without pH adjustment. Furthermore, calcium carbonate could play dual roles as both buffering agency and activator for NAD kinase (NADK), and supplementation of 10 g/L calcium carbonate could finally improve the IBE production to 17.77 g/L with 10.51, 6.02, and 1.24 g/L of butanol, isopropanol, and ethanol. CONCLUSION The complete conversion of acetone into isopropanol in the recombinant C. acetobutylicum XY16 harboring pSADH could alter ABE to IBE. pH control strategies and supplementation of calcium carbonate were effective in obtaining high IBE titer with high isopropanol production. The analysis of redox cofactor perturbation indicates that the availability of NAD(P)H is the main driving force for the improvement of IBE production.
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Affiliation(s)
- Chao Wang
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Puzhu South Road 30#, Nanjing, 211816 People’s Republic of China
| | - Fengxue Xin
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Puzhu South Road 30#, Nanjing, 211816 People’s Republic of China
- Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University, Nanjing, 211816 People’s Republic of China
| | - Xiangping Kong
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Puzhu South Road 30#, Nanjing, 211816 People’s Republic of China
| | - Jie Zhao
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Puzhu South Road 30#, Nanjing, 211816 People’s Republic of China
| | - Weiliang Dong
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Puzhu South Road 30#, Nanjing, 211816 People’s Republic of China
- Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University, Nanjing, 211816 People’s Republic of China
| | - Wenming Zhang
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Puzhu South Road 30#, Nanjing, 211816 People’s Republic of China
- Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University, Nanjing, 211816 People’s Republic of China
| | - Jiangfeng Ma
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Puzhu South Road 30#, Nanjing, 211816 People’s Republic of China
- Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University, Nanjing, 211816 People’s Republic of China
| | - Hao Wu
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Puzhu South Road 30#, Nanjing, 211816 People’s Republic of China
- Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University, Nanjing, 211816 People’s Republic of China
| | - Min Jiang
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Puzhu South Road 30#, Nanjing, 211816 People’s Republic of China
- Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University, Nanjing, 211816 People’s Republic of China
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8
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On-line monitoring of relevant fluorophores of yeast cultivations due to glucose addition during the diauxic growth. Process Biochem 2017. [DOI: 10.1016/j.procbio.2017.05.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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9
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Wu Y, Li H, Zhang XM, Gong JS, Li H, Rao ZM, Shi JS, Xu ZH. Improvement of NADPH-dependent P450-mediated biotransformation of 7α,15α-diOH-DHEA from DHEA by a dual cosubstrate-coupled system. Steroids 2015; 101:15-20. [PMID: 26032779 DOI: 10.1016/j.steroids.2015.05.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Revised: 04/25/2015] [Accepted: 05/24/2015] [Indexed: 12/16/2022]
Abstract
Hydroxylation of DHEA to 7α,15α-diOH-DHEA was catalyzed by NADPH-dependent cytochrome P450 monooxygenase from Colletotrichum lini. By adding coenzyme precursor nicotinic acid, the NADPH/NADP ratio was significantly increased, and the 7α,15α-diOH-DHEA molar conversion was enhanced from 37.37% to 50.85%. To improve the availability of intracellular NADPH, a dual cosubstrate-coupled system consisting of nicotinic acid and glucose was investigated in C. lini. Using 20mM nicotinic acid and 15g/L glucose as cosubstrate for NADPH regeneration, the 7α,15α-diOH-DHEA molar conversion was dramatically increased by 74.58%. The conversion course was simultaneously shortened by 30h. Moreover, a fed-batch transformation model was established to diminish DHEA toxicity to C. lini and further increase DHEA concentration. The maximum concentration of DHEA was elevated to 15g/L using a three-batch transformation in a coenzyme regeneration system, and 7α,15α-diOH-DHEA production of 11.21g/L could be achieved after 60h of biotransformation. These results demonstrated that this strategy was promising for steroids hydroxylation.
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Affiliation(s)
- Yan Wu
- School of Pharmaceutical Science, Jiangnan University, Wuxi 214122, People's Republic of China; The Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi, People's Republic of China
| | - Hui Li
- School of Pharmaceutical Science, Jiangnan University, Wuxi 214122, People's Republic of China
| | - Xiao-Mei Zhang
- School of Pharmaceutical Science, Jiangnan University, Wuxi 214122, People's Republic of China
| | - Jin-Song Gong
- School of Pharmaceutical Science, Jiangnan University, Wuxi 214122, People's Republic of China
| | - Heng Li
- School of Pharmaceutical Science, Jiangnan University, Wuxi 214122, People's Republic of China
| | - Zhi-Ming Rao
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi, People's Republic of China
| | - Jin-Song Shi
- School of Pharmaceutical Science, Jiangnan University, Wuxi 214122, People's Republic of China
| | - Zheng-Hong Xu
- School of Pharmaceutical Science, Jiangnan University, Wuxi 214122, People's Republic of China.
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Wang G, Huang D, Li Y, Wen J, Jia X. A metabolic-based approach to improve xylose utilization for fumaric acid production from acid pretreated wheat bran by Rhizopus oryzae. BIORESOURCE TECHNOLOGY 2015; 180:119-127. [PMID: 25594507 DOI: 10.1016/j.biortech.2014.12.091] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Revised: 12/24/2014] [Accepted: 12/26/2014] [Indexed: 06/04/2023]
Abstract
In this work, wheat bran (WB) was utilized as feedstock to synthesize fumaric acid by Rhizopus oryzae. Firstly, the pretreatment process of WB by dilute sulfuric acid hydrolysis undertaken at 100°C for 30min offered the best performance for fumaric acid production. Subsequently, through optimizing the seed culture medium, a suitable morphology (0.55mm pellets diameter) of R. oryzae was obtained. Furthermore, a metabolic-based approach was developed to profile the differences of intracellular metabolites concentration of R. oryzae between xylose (the abundant sugar in wheat bran hydrolysate (WBH)) and glucose metabolism. The xylitol, sedoheptulose 7-phosphate, ribulose 5-phosphate, glucose 6-phosphate, proline and serine were responsible for fumaric acid biosynthesis limitation in xylose fermentation. Consequently, regulation strategies were proposed, leading to a 149% increase in titer (up to 15.4g/L). Finally, by combinatorial regulation strategies the highest production was 20.2g/L from WBH, 477% higher than that of initial medium.
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Affiliation(s)
- Guanyi Wang
- Key Laboratory of System Bioengineering (Tianjin University), Ministry of Education, Tianjin 300072, People's Republic of China; SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), 300072, People's Republic of China
| | - Di Huang
- TEDA School of Biological Sciences and Biotechnology, Nankai University, TEDA, Tianjin 300457, People's Republic of China
| | - Yong Li
- Key Laboratory of System Bioengineering (Tianjin University), Ministry of Education, Tianjin 300072, People's Republic of China; SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), 300072, People's Republic of China
| | - Jianping Wen
- Key Laboratory of System Bioengineering (Tianjin University), Ministry of Education, Tianjin 300072, People's Republic of China; SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), 300072, People's Republic of China.
| | - Xiaoqiang Jia
- Key Laboratory of System Bioengineering (Tianjin University), Ministry of Education, Tianjin 300072, People's Republic of China; SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), 300072, People's Republic of China
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Li T, Yan Y, He J. Enhanced direct fermentation of cassava to butanol by Clostridium species strain BOH3 in cofactor-mediated medium. BIOTECHNOLOGY FOR BIOFUELS 2015; 8:166. [PMID: 26464582 PMCID: PMC4603972 DOI: 10.1186/s13068-015-0351-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Accepted: 09/30/2015] [Indexed: 05/07/2023]
Abstract
BACKGROUND The main challenge of cassava-based biobutanol production is to enhance the simultaneous saccharification and fermentation with high hyperamylolytic activity and butanol yield. Manipulation of cofactor [e.g., Ca(2+) and NAD/(P)H] levels as a potential tool to modulate carbon flux plays a key role in the cassava hydrolysis capacity and butanol productivity. Here, we aimed to develop a technology for enhancing butanol production with simultaneous hydrolysis of cassava (a typical model as a non-cereal starchy material) using a cofactor-dependent modulation method to maximize the production efficacy of biobutanol by Clostridium sp. stain BOH3. RESULTS Supplementing CaCO3 to the medium containing cassava significantly promotes activities of α-amylase responsible for cassava hydrolysis and butanol production due to the role of Ca(2+) cofactor-dependent pathway in conversion of cassava starch to reducing sugar and its buffering capacity. Also, after applying redox modulation with l-tryptophan (a precursor as de novo synthesis of NADH and NADPH), the levels of cofactor NADH and NADPH increased significantly by 67 % in the native cofactor-dependent system of the wild-type Clostridium sp. stain BOH3. Increasing availability of NADH and NADPH improved activities of NADH- and NADPH-dependent butanol dehydrogenases, and thus could selectively open the valve of carbon flux toward the more reduced product, butanol, against the more oxidized acid or acetone products. By combining CaCO3 and l-tryptophan, 17.8 g/L butanol with a yield of 30 % and a productivity of 0.25 g/L h was obtained with a hydrolytic capacity of 88 % towards cassava in a defined medium. The metabolic patterns were shifted towards more reduced metabolites as reflected by higher butanol-acetone ratio (76 %) and butanol-bioacid ratio (500 %). CONCLUSIONS The strategy of altering enzyme cofactor supply may provide an alternative tool to enhance the stimulation of saccharification and fermentation in a cofactor-dependent production system. While genetic engineering focuses on strain improvement to enhance butanol production, cofactor technology can fully exploit the productivity of a strain and maximize the production efficiency.
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Affiliation(s)
- Tinggang Li
- Department of Civil and Environmental Engineering, National University of Singapore, Block E2-02-13, 1 Engineering Drive 3, Singapore, 117576 Singapore
| | - Yu Yan
- Department of Civil and Environmental Engineering, National University of Singapore, Block E2-02-13, 1 Engineering Drive 3, Singapore, 117576 Singapore
| | - Jianzhong He
- Department of Civil and Environmental Engineering, National University of Singapore, Block E2-02-13, 1 Engineering Drive 3, Singapore, 117576 Singapore
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12
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Li T, Yan Y, He J. Reducing cofactors contribute to the increase of butanol production by a wild-type Clostridium sp. strain BOH3. BIORESOURCE TECHNOLOGY 2014; 155:220-8. [PMID: 24463410 DOI: 10.1016/j.biortech.2013.12.089] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Revised: 12/16/2013] [Accepted: 12/19/2013] [Indexed: 05/10/2023]
Abstract
Availability of reducing factors (e.g., NADH and NADPH) plays an important role in improving the efficacy of products conversion in cofactor-dependent production systems. In this study, nicotinic acid (NA), the precursor of NADH and NADPH, was supplemented to the growth medium of a wild-type Clostridium sp. strain BOH3. Results showed that the addition of precursor NA to the medium led to a significant increase in the levels of NADH and NADPH. Meanwhile, a maximal cell growth rate and butanol generation rate were reached by applying a two-stage pH-shift strategy, achieving 18.7g/L butanol with a yield of 24.6% and a productivity of 0.26g/Lh. The metabolic patterns were shifted towards more reduced metabolites as reflected by higher butanol-to-acetone ratio (11%) and butanol-to-acid ratio (292%). Redistributing metabolic flux to butanol via manipulations of reducing cofactor and pH shift could become an alternative tool to realize metabolic engineering goals.
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Affiliation(s)
- Tinggang Li
- Department of Civil and Environmental Engineering, National University of Singapore, Singapore 117576, Singapore
| | - Yu Yan
- Department of Civil and Environmental Engineering, National University of Singapore, Singapore 117576, Singapore
| | - Jianzhong He
- Department of Civil and Environmental Engineering, National University of Singapore, Singapore 117576, Singapore.
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Determining the extremes of the cellular NAD(H) level by using an Escherichia coli NAD(+)-auxotrophic mutant. Appl Environ Microbiol 2011; 77:6133-40. [PMID: 21742902 DOI: 10.1128/aem.00630-11] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
NAD (NAD(+)) and its reduced form (NADH) are omnipresent cofactors in biological systems. However, it is difficult to determine the extremes of the cellular NAD(H) level in live cells because the NAD(+) level is tightly controlled by a biosynthesis regulation mechanism. Here, we developed a strategy to determine the extreme NAD(H) levels in Escherichia coli cells that were genetically engineered to be NAD(+) auxotrophic. First, we expressed the ntt4 gene encoding the NAD(H) transporter in the E. coli mutant YJE001, which had a deletion of the nadC gene responsible for NAD(+) de novo biosynthesis, and we showed NTT4 conferred on the mutant strain better growth in the presence of exogenous NAD(+). We then constructed the NAD(+)-auxotrophic mutant YJE003 by disrupting the essential gene nadE, which is responsible for the last step of NAD(+) biosynthesis in cells harboring the ntt4 gene. The minimal NAD(+) level was determined in M9 medium in proliferating YJE003 cells that were preloaded with NAD(+), while the maximal NAD(H) level was determined by exposing the cells to high concentrations of exogenous NAD(H). Compared with supplementation of NADH, cells grew faster and had a higher intracellular NAD(H) level when NAD(+) was fed. The intracellular NAD(H) level increased with the increase of exogenous NAD(+) concentration, until it reached a plateau. Thus, a minimal NAD(H) level of 0.039 mM and a maximum of 8.49 mM were determined, which were 0.044× and 9.6× those of wild-type cells, respectively. Finally, the potential application of this strategy in biotechnology is briefly discussed.
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