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Wang X, Qiu C, Chen C, Gao C, Wei W, Song W, Wu J, Liu L, Chen X. Metabolic Engineering of Escherichia coli for High-Level Production of l-Phenylalanine. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2024; 72:11029-11040. [PMID: 38699920 DOI: 10.1021/acs.jafc.4c01563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2024]
Abstract
l-Phenylalanine (l-Phe) is widely used in the food and pharmaceutical industries. However, the biosynthesis of l-Phe using Escherichia coli remains challenging due to its lower tolerance to high concentration of l-Phe. In this study, to efficiently synthesize l-Phe, the l-Phe biosynthetic pathway was reconstructed by expressing the heterologous genes aroK1, aroL1, and pheA1, along with the native genes aroA, aroC, and tyrB in the shikimate-producing strain E. coli SA09, resulting in the engineered strain E. coli PHE03. Subsequently, adaptive evolution was conducted on E. coli PHE03 to enhance its tolerance to high concentrations of l-Phe, resulting in the strain E. coli PHE04, which reduced the cell mortality to 36.2% after 48 h of fermentation. To elucidate the potential mechanisms, transcriptional profiling was conducted, revealing MarA, a DNA-binding transcriptional dual regulator, as playing a crucial role in enhancing cell membrane integrity and fluidity for improving cell tolerance to high concentrations of l-Phe. Finally, the titer, yield, and productivity of l-Phe with E. coli PHE05 overexpressing marA were increased to 80.48 g/L, 0.27 g/g glucose, and 1.68 g/L/h in a 5-L fed-batch fermentation, respectively.
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Affiliation(s)
- Xiaoge Wang
- School of Biotechnology, Jiangnan University, Wuxi 214122, China
- Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China
| | - Chong Qiu
- School of Biotechnology, Jiangnan University, Wuxi 214122, China
- Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China
| | - Chenghu Chen
- School of Biotechnology, Jiangnan University, Wuxi 214122, China
- Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China
| | - Cong Gao
- School of Biotechnology, Jiangnan University, Wuxi 214122, China
- Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China
| | - Wanqing Wei
- School of Biotechnology, Jiangnan University, Wuxi 214122, China
- Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China
| | - Wei Song
- School of Life Sciences and Health Engineering, Jiangnan University, Wuxi 214122, China
| | - Jing Wu
- School of Life Sciences and Health Engineering, Jiangnan University, Wuxi 214122, China
| | - Liming Liu
- School of Biotechnology, Jiangnan University, Wuxi 214122, China
- Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China
| | - Xiulai Chen
- School of Biotechnology, Jiangnan University, Wuxi 214122, China
- Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China
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2
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Tong Z, Tong Y, Wang D, Shi Y. Whole Maize Flour and Isolated Maize Starch for Production of Citric Acid by
Aspergillus niger
: A Review. STARCH-STARKE 2021. [DOI: 10.1002/star.202000014] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Zhenyu Tong
- Department of Grain Science and Industry Kansas State University Manhattan KS 66506 USA
| | - Yi Tong
- COFCO Biochemical (Anhui) Co., Ltd Bengbu 233000 P. R. China
| | - Donghai Wang
- Department of Biological and Agricultural Engineering Kansas State University Manhattan KS 66506 USA
| | - Yong‐Cheng Shi
- Department of Grain Science and Industry Kansas State University Manhattan KS 66506 USA
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3
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Construction of recombinant Escherichia coli for production of L-phenylalanine-derived compounds. World J Microbiol Biotechnol 2021; 37:84. [PMID: 33855641 DOI: 10.1007/s11274-021-03050-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Accepted: 04/03/2021] [Indexed: 10/21/2022]
Abstract
L-phenylalanine is an important amino acid that is widely used in the fields of food flavors and pharmaceuticals. Apart from L-phenylalanine itself, various commercially valuable chemical compounds can also be generated via the L-phenylalanine biosynthesis pathway. Compared with direct extraction from plants or synthesis by chemical reaction, microbial production of L-phenylalanine -derived compounds can overcome the drawbacks of environmental pollution, low yield, and mixtures of stereoisomeric products. Accordingly, increasing intracellular levels of precursors, deregulating feedback inhibition and transcription repression, engineering global regulators and other effective strategies have been implemented to produce different L-phenylalanine -derived compounds in the excellent chassis host Escherichia coli. Finally, this review highlights principal strategies for improving the production of L-phenylalanine and/or its derivatives in E. coli, and discusses the future outlook for further enhancing the titer and yields of these compounds.
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4
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Analyzing the genetic characteristics of a tryptophan-overproducing Escherichia coli. Bioprocess Biosyst Eng 2021; 44:1685-1697. [PMID: 33748869 DOI: 10.1007/s00449-021-02552-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Accepted: 03/12/2021] [Indexed: 10/21/2022]
Abstract
L-tryptophan (L-trp) production in Escherichia coli has been developed by employing random mutagenesis and selection for a long time, but this approach produces an unclear genetic background. Here, we generated the L-trp overproducer TPD5 by combining an intracellular L-trp biosensor and fluorescence-activated cell sorting (FACS) in E. coli, and succeeded in elucidating the genetic basis for L-trp overproduction. The most significant identified positive mutations affected TnaA (deletion), AroG (S211F), TrpE (A63V), and RpoS (nonsense mutation Q33*). The underlying structure-function relationships of the feedback-resistant AroG (S211F) and TrpE (A63V) mutants were uncovered based on protein structure modeling and molecular dynamics simulations, respectively. According to transcriptomic analysis, the global regulator RpoS not only has a great influence on cell growth and morphology, but also on carbon utilization and the direction of carbon flow. Finally, by balancing the concentrations of the L-trp precursors' serine and glutamine based on the above analysis, we further increased the titer of L-trp to 3.18 g/L with a yield of 0.18 g/g. The analysis of the genetic characteristics of an L-trp overproducing E. coli provides valuable information on L-trp synthesis and elucidates the phenotype and complex cellular properties in a high-yielding strain, which opens the possibility to transfer beneficial mutations and reconstruct an overproducer with a clean genetic background.
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5
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Zhao C, Fang H, Wang J, Zhang S, Zhao X, Li Z, Lin C, Shen Z, Cheng L. Application of fermentation process control to increase l-tryptophan production in Escherichia coli. Biotechnol Prog 2019; 36:e2944. [PMID: 31804750 DOI: 10.1002/btpr.2944] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 11/04/2019] [Accepted: 11/26/2019] [Indexed: 11/11/2022]
Abstract
In this study, process engineering and process control were applied to increase the production of l-tryptophan using Escherichia coli Dmtr/pta-Y. Different dissolved oxygen (DO) and pH control strategies were applied in l-tryptophan production. DO and pH were maintained at [20% (0-20 hr); 30% (20-40 hr)] and [7.0 (0-20 hr), 6.5 (20-40 hr)], respectively, which increased l-tryptophan production, glucose conversion percentage [g (l-tryptophan)/g (glucose)], and transcription levels of key genes for tryptophan biosynthesis and tryptophan biosynthesis flux, and decreased the accumulation of acetate and transcription levels of genes related to acetate synthesis and acetate synthesis flux. Using E. coli Dmtr/pta-Y with optimized DO [20% (0-20 hr); 30% (20-40 hr)] and pH [7.0 (0-20 hr), 6.5 (20-40 hr)] values, the highest l-tryptophan production (52.57 g/L) and glucose conversion percentage (20.15%) were obtained. The l-tryptophan production was increased by 26.58%, the glucose conversion percentage was increased by 22.64%, and the flux of tryptophan biosynthesis was increased to 21.5% compared with different conditions for DO [50% (0-20 hr), 20% (20-40 hr)] and pH [7.0].
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Affiliation(s)
- Chunguang Zhao
- Key Laboratory of Fermentation Engineering, Shandong Binzhou Animal Science and Veterinary Medicine Academy, Binzhou, China.,School of Agriculture, Ningxia University, Ningxia Eppen Biotech Co., Ltd, Yinchuan, China
| | - Haitian Fang
- School of Agriculture, Ningxia University, Ningxia Eppen Biotech Co., Ltd, Yinchuan, China
| | - Jing Wang
- Key Laboratory of Fermentation Engineering, Shandong Binzhou Animal Science and Veterinary Medicine Academy, Binzhou, China.,Department of Critical Care Medicine, Affiliated Hospital of Binzhou Medical University, Binzhou, China
| | - Shasha Zhang
- Key Laboratory of Fermentation Engineering, Shandong Binzhou Animal Science and Veterinary Medicine Academy, Binzhou, China
| | - Xiubao Zhao
- Key Laboratory of Fermentation Engineering, Shandong Binzhou Animal Science and Veterinary Medicine Academy, Binzhou, China
| | - Zengliang Li
- Shandong Research Center of High Cell Density Fermentation and Efficient Expression Technology, Shandong Lvdu Bio-science and Technology Co., Ltd, Binzhou, China
| | - Chuwen Lin
- Key Laboratory of Fermentation Engineering, Shandong Binzhou Animal Science and Veterinary Medicine Academy, Binzhou, China.,Shandong Research Center of High Cell Density Fermentation and Efficient Expression Technology, Shandong Lvdu Bio-science and Technology Co., Ltd, Binzhou, China
| | - Zhiqiang Shen
- Key Laboratory of Fermentation Engineering, Shandong Binzhou Animal Science and Veterinary Medicine Academy, Binzhou, China.,Shandong Research Center of High Cell Density Fermentation and Efficient Expression Technology, Shandong Lvdu Bio-science and Technology Co., Ltd, Binzhou, China
| | - Likun Cheng
- Key Laboratory of Fermentation Engineering, Shandong Binzhou Animal Science and Veterinary Medicine Academy, Binzhou, China.,Shandong Research Center of High Cell Density Fermentation and Efficient Expression Technology, Shandong Lvdu Bio-science and Technology Co., Ltd, Binzhou, China
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6
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Tröndle J, Schoppel K, Bleidt A, Trachtmann N, Sprenger GA, Weuster-Botz D. Metabolic control analysis of L-tryptophan production with Escherichia coli based on data from short-term perturbation experiments. J Biotechnol 2019; 307:15-28. [PMID: 31639341 DOI: 10.1016/j.jbiotec.2019.10.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2019] [Accepted: 10/10/2019] [Indexed: 12/21/2022]
Abstract
E. coli strain NT1259 /pF112aroFBLkan was able to produce 14.3 g L-1 L-tryptophan within 68 h in a fed-batch process from glycerol on a 15 L scale. To gain detailed insight into metabolism of this E. coli strain in the fed-batch process, a sample of L-tryptophan producing cells was withdrawn after 47 h, was separated rapidly and then resuspended in four parallel stirred-tank bioreactors with fresh media. Four different carbon sources (glucose, glycerol, succinate, pyruvate) were supplied individually with varying feeding rates within 19 min and the metabolic reactions of the cells in the four parallel reactors were analyzed by quantification of extracellular and intracellular substrate, product and metabolite concentrations. Data analysis allowed the estimation of intracellular carbon fluxes and of thermodynamic limitations concerning intracellular concentrations and reaction energies. Carbon fluxes and intracellular metabolite concentrations enabled the estimation of elasticities and flux control coefficients by applying metabolic control analysis making use of a metabolic model considering 48 enzymatic reactions and 56 metabolites. As the flux control coefficients describe connections between enzyme activities and metabolic fluxes, they reveal genetic targets for strain improvement. Metabolic control analysis of the recombinant E. coli cells withdrawn from the fed-batch production process clearly indicated that (i) the supply of two precursors for L-tryptophan biosynthesis, L-serine and phosphoribosyl-pyrophosphate, as well as (ii) the formation of aromatic byproducts and (iii) the enzymatic steps of igps and trps2 within the L-tryptophan biosynthesis pathway have major impact on fed-batch production of L-tryptophan from glycerol and should be the targets for further strain improvements.
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Affiliation(s)
- Julia Tröndle
- Technical University of Munich, Institute of Biochemical Engineering, Boltzmannstr. 15, 85748, Garching, Germany
| | - Kristin Schoppel
- Technical University of Munich, Institute of Biochemical Engineering, Boltzmannstr. 15, 85748, Garching, Germany
| | - Arne Bleidt
- Technical University of Munich, Institute of Biochemical Engineering, Boltzmannstr. 15, 85748, Garching, Germany
| | - Natalia Trachtmann
- University of Stuttgart, Institute of Microbiology, Allmandring 31, 70569, Stuttgart, Germany
| | - Georg A Sprenger
- University of Stuttgart, Institute of Microbiology, Allmandring 31, 70569, Stuttgart, Germany
| | - Dirk Weuster-Botz
- Technical University of Munich, Institute of Biochemical Engineering, Boltzmannstr. 15, 85748, Garching, Germany.
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7
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Metabolic Engineering and Fermentation Process Strategies for L-Tryptophan Production by Escherichia coli. Processes (Basel) 2019. [DOI: 10.3390/pr7040213] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
L-tryptophan is an essential aromatic amino acid that has been widely used in medicine, food, and animal feed. Microbial biosynthesis of L-tryptophan through metabolic engineering approaches represents a sustainable, cost-effective, and environmentally friendly route compared to chemical synthesis. In particular, metabolic pathway engineering allows enhanced product titers by inactivating/blocking the competing pathways, increasing the intracellular level of essential precursors, and overexpressing rate-limiting enzymatic steps. Based on the route of the l-tryptophan biosynthesis pathway, this review presents a systematic and detailed summary of the contemporary metabolic engineering approaches employed for l-tryptophan production. In addition to the engineering of the l-tryptophan biosynthesis pathway, the metabolic engineering modification of carbon source uptake, by-product formation, key regulatory factors, and the polyhydroxybutyrate biosynthesis pathway in l-tryptophan biosynthesis are discussed. Moreover, fermentation bioprocess optimization strategies used for l-tryptophan overproduction are also delineated. Towards the end, the review is wrapped up with the concluding remarks, and future strategies are outlined for the development of a high l-tryptophan production strain.
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8
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Metabolic engineering for improving l-tryptophan production in Escherichia coli. ACTA ACUST UNITED AC 2019; 46:55-65. [DOI: 10.1007/s10295-018-2106-5] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 11/03/2018] [Indexed: 11/26/2022]
Abstract
Abstract
l-Tryptophan is an important aromatic amino acid that is used widely in the food, chemical, and pharmaceutical industries. Compared with the traditional synthetic methods, production of l-tryptophan by microbes is environmentally friendly and has low production costs, and feed stocks are renewable. With the development of metabolic engineering, highly efficient production of l-tryptophan in Escherichia coli has been achieved by eliminating negative regulation factors, improving the intracellular level of precursors, engineering of transport systems and overexpression of rate-limiting enzymes. However, challenges remain for l-tryptophan biosynthesis to be cost-competitive. In this review, successful and applicable strategies derived from metabolic engineering for increasing l-tryptophan accumulation in E. coli are summarized. In addition, perspectives for further efficient production of l-tryptophan are discussed.
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9
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Tröndle J, Trachtmann N, Sprenger GA, Weuster-Botz D. Fed-batch production ofl-tryptophan from glycerol using recombinantEscherichia coli. Biotechnol Bioeng 2018; 115:2881-2892. [DOI: 10.1002/bit.26834] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 08/27/2018] [Accepted: 09/05/2018] [Indexed: 01/21/2023]
Affiliation(s)
- Julia Tröndle
- Institute of Biochemical Engineering, Department of Mechanical Engineering Technical University of Munich; Garching Germany
| | - Natalia Trachtmann
- Institute of Microbiology, Center of Biochemical Engineering, University of Stuttgart; Stuttgart Germany
| | - Georg A. Sprenger
- Institute of Microbiology, Center of Biochemical Engineering, University of Stuttgart; Stuttgart Germany
| | - Dirk Weuster-Botz
- Institute of Biochemical Engineering, Department of Mechanical Engineering Technical University of Munich; Garching Germany
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10
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Xu Q, Bai F, Chen N, Bai G. Removing the by-products acetic acid and NH 4 + from the l -tryptophan broth by vacuum thin film evaporation during l -tryptophan production. ELECTRON J BIOTECHN 2018. [DOI: 10.1016/j.ejbt.2018.04.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022] Open
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11
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Gene modification of Escherichia coli and incorporation of process control to decrease acetate accumulation and increase ʟ-tryptophan production. ANN MICROBIOL 2017. [DOI: 10.1007/s13213-017-1289-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
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12
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Wang B, Li H, Zhu L, Tan F, Li Y, Zhang L, Ding Z, Shi G. High-efficient production of citric acid by Aspergillus niger from high concentration of substrate based on the staged-addition glucoamylase strategy. Bioprocess Biosyst Eng 2017; 40:891-899. [DOI: 10.1007/s00449-017-1753-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Accepted: 02/14/2017] [Indexed: 11/25/2022]
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13
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Rational design and metabolic analysis of Escherichia coli for effective production of L-tryptophan at high concentration. Appl Microbiol Biotechnol 2016; 101:559-568. [DOI: 10.1007/s00253-016-7772-5] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Accepted: 08/01/2016] [Indexed: 01/09/2023]
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14
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Lin C, Cheng L, Wang J, Zhang S, Fu Q, Li S, Li F, Han W, Shen Z. Optimization of culture conditions to improve the expression level of beta1–epsilon toxin ofClostridium perfringenstype B inEscherichia coli. BIOTECHNOL BIOTEC EQ 2016. [DOI: 10.1080/13102818.2015.1126201] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
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15
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A pH shift feeding strategy for increased enduracidin production during fed–batch fermentation by a deep–sea, bacterium, Streptomyces sp. MC079. BIOTECHNOL BIOPROC E 2015. [DOI: 10.1007/s12257-015-0251-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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16
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Improvement of the production of L-tryptophan in Escherichia coli by application of a dissolved oxygen stage control strategy. ANN MICROBIOL 2015. [DOI: 10.1007/s13213-015-1172-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
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17
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Wang J, Wen B, Xu Q, Xie X, Chen N. Optimization of carbon source and glucose feeding strategy for improvement of L-isoleucine production by Escherichia coli. BIOTECHNOL BIOTEC EQ 2015; 29:374-380. [PMID: 26019655 PMCID: PMC4433842 DOI: 10.1080/13102818.2015.1006899] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2014] [Accepted: 10/24/2014] [Indexed: 11/30/2022] Open
Abstract
Fed-batch cultivations of L-isoleucine-producing Escherichia coli TRFP (SGr, α-ABAr, with a pTHR101 plasmid containing a thr operon and ilvA) were carried out on different carbon sources: glucose, sucrose, fructose, maltose and glycerol. The results indicated that sucrose was the best initial carbon source for L-isoleucine production and then sucrose concentration of 30 g·L−1 was determined in the production medium. The results of different carbon sources feeding showed that the glucose solution was the most suitable feeding media. The dissolved oxygen (DO) of L-isoleucine fermentation was maintained at 5%, 15% and 30% with DO-stat feeding, respectively. The results indicated that when the DO level was maintained at 30%, the highest biomass and L-isoleucine production were obtained. The accumulation of acetate was decreased and the production of L-isoleucine was increased markedly, when the glucose concentration was maintained at 0.15 g·L−1 by using glucose-stat feeding. Finally, the glucose concentration was maintained at 0.10 g·L−1 and the DO level was controlled at approximately 30% during the whole fermentation period, using the combined feeding strategy of glucose-stat feeding and DO feedback feeding. The acetate accumulation was decreased to 7.23 g·L−1, and biomass and production of L-isoleucine were increased to 46.8 and 11.95 g·L−1, respectively.
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Affiliation(s)
- Jian Wang
- Department of Bioengineering, College of Biological and Agricultural Engineering, Jilin University, Changchun , Jilin , China
| | - Bing Wen
- National and Local United Engineering Lab of Metabolic Control Fermentation Technology, Tianjin University of Science and Technology , Tianjin , China ; Key Laboratory of Industrial Microbiology of Education Ministry, Tianjin University of Science and Technology , Tianjin , China ; Tianjin Research Institute of Industrial Microbiology , Tianjin , China
| | - Qingyang Xu
- National and Local United Engineering Lab of Metabolic Control Fermentation Technology, Tianjin University of Science and Technology , Tianjin , China ; Key Laboratory of Industrial Microbiology of Education Ministry, Tianjin University of Science and Technology , Tianjin , China
| | - Xixian Xie
- National and Local United Engineering Lab of Metabolic Control Fermentation Technology, Tianjin University of Science and Technology , Tianjin , China ; Key Laboratory of Industrial Microbiology of Education Ministry, Tianjin University of Science and Technology , Tianjin , China
| | - Ning Chen
- National and Local United Engineering Lab of Metabolic Control Fermentation Technology, Tianjin University of Science and Technology , Tianjin , China ; Key Laboratory of Industrial Microbiology of Education Ministry, Tianjin University of Science and Technology , Tianjin , China
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Jin H, Chen X, Yang J, Wu L, Wang L. Hybrid intelligent control of substrate feeding for industrial fed-batch chlortetracycline fermentation process. ISA TRANSACTIONS 2014; 53:1822-1837. [PMID: 25245525 DOI: 10.1016/j.isatra.2014.08.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2014] [Revised: 08/23/2014] [Accepted: 08/30/2014] [Indexed: 06/03/2023]
Abstract
The lack of accurate process models and reliable online sensors for substrate measurements poses significant challenges for controlling substrate feeding accurately, automatically and optimally in fed-batch fermentation industries. It is still a common practice to regulate the feeding rate based upon manual operations. To address this issue, a hybrid intelligent control method is proposed to enable automatic substrate feeding. The resulting control system consists of three modules: a presetting module for providing initial set-points; a predictive module for estimating substrate concentration online based on a new time interval-varying soft sensing algorithm; and a feedback compensator using expert rules. The effectiveness of the proposed approach is demonstrated through its successful applications to the industrial fed-batch chlortetracycline fermentation process.
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Affiliation(s)
- Huaiping Jin
- Department of Chemical Engineering, Beijing Institute of Technology, Beijing 100081, People׳s Republic of China.
| | - Xiangguang Chen
- Department of Chemical Engineering, Beijing Institute of Technology, Beijing 100081, People׳s Republic of China.
| | - Jianwen Yang
- Department of Chemical Engineering, Beijing Institute of Technology, Beijing 100081, People׳s Republic of China.
| | - Lei Wu
- Department of Chemical Engineering, Beijing Institute of Technology, Beijing 100081, People׳s Republic of China.
| | - Li Wang
- Department of Chemical Engineering, Beijing Institute of Technology, Beijing 100081, People׳s Republic of China.
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19
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Construction and expression of mutagenesis strain of aroG gene from Escherichia coli K-12. Int J Biol Macromol 2014; 68:173-7. [DOI: 10.1016/j.ijbiomac.2014.04.034] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Revised: 03/25/2014] [Accepted: 04/17/2014] [Indexed: 11/22/2022]
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20
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Tang Y, Gan M, Xie Y, Li X, Chen L. Fast screening of bacterial suspension culture conditions on chips. LAB ON A CHIP 2014; 14:1162-1167. [PMID: 24477551 DOI: 10.1039/c3lc51332g] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Culture conditions including pH, nutrient concentration and temperature strongly influence the properties of a microbial strain by affecting many factors such as the microbial membrane and metabolism. We present a microfluidic chip for screening pH and nutrient content with a concentration gradient generator connected to eight parallel suspension culture loops and another chip for the screening of temperature with four different temperature zones under suspension culture loops. Bacteria grow much faster on chips than in test tubes, and yet interestingly, on-chip screening of culture conditions for E. coli yields results similar to those from a culture in test tubes, demonstrating the validity of the on-chip screening approach. The microfluidic chips were applied to study the growth conditions of two wild type Bacillus subtilis strains isolated from polluted water. The on-chip screening experiments show advantages of nanoliter scale screening units, high-throughput and requiring only one-fourth of the time.
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Affiliation(s)
- Yunfang Tang
- i-LAB, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, 398 Ruoshui Road, Suzhou Industrial Park, Suzhou, PR China.
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21
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Wang J, Cheng LK, Wang J, Liu Q, Shen T, Chen N. Genetic engineering of Escherichia coli to enhance production of L-tryptophan. Appl Microbiol Biotechnol 2013; 97:7587-96. [PMID: 23775271 DOI: 10.1007/s00253-013-5026-3] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2013] [Revised: 05/08/2013] [Accepted: 05/30/2013] [Indexed: 10/26/2022]
Abstract
Reducing the accumulation of acetate in Escherichia coli cultures can decrease carbon efflux as by-products and reduce acetate toxicity, and therefore enable high cell density cultivation. The concentration of intracellular amino acids can be decreased by genetic modifications of the corresponding amino acid transport systems. This can increase the levels of amino acids in the fermentation broth by decreasing the feedback inhibition on the corresponding biosynthetic pathways. Here, the effects of genetic manipulation of phosphate acetyltransferase (pta), high affinity tryptophan transporter (mtr) and aromatic amino acid exporter (yddG) on L-tryptophan production were investigated. The pta mutants accumulated less acetate and showed higher capacity for producing L-tryptophan as compared with the parental strain. The strains lacking mtr, or overexpressed yddG, or with the both mtr knockout and yddG overexpression, accumulated lower concentrations of intracellular tryptophan but higher production of extracellular L-tryptophan. In the L-tryptohan fed-batch fermentation of an E. coli derived from TRTH0709/pMEL03 having deletion of pta-mtr and overexpression of yddG in a 30-L fermentor, the maximum concentration of L-tryptophan (48.68 g/L) was obtained, which represented a 15.96 % increase as compared with the parental strain. Acetate accumulated to a concentration of 0.95 g/L. The intracellular concentration of L-tryptophan was low, and the glucose conversion rate reached a high level of 21.87 %, which was increased by 15.53 % as compared with the parent strain.
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Affiliation(s)
- Jian Wang
- College of Biological and Agricultural Engineering, Jilin University, Changchun, 130022, People's Republic of China.
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