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Zhou Z, Li Z, Zhong Y, Xu S, Li Z. Engineering of the Lrp/AsnC-type transcriptional regulator DecR as a genetically encoded biosensor for multilevel optimization of L-cysteine biosynthesis pathway in Escherichia coli. Biotechnol Bioeng 2024; 121:2133-2146. [PMID: 38634289 DOI: 10.1002/bit.28716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Revised: 03/27/2024] [Accepted: 04/08/2024] [Indexed: 04/19/2024]
Abstract
L-cysteine is an important sulfur-containing amino acid being difficult to produce by microbial fermentation. Due to the lack of high-throughput screening methods, existing genetically engineered bacteria have been developed by simply optimizing the expression of L-cysteine-related genes one by one. To overcome this limitation, in this study, a biosensor-based approach for multilevel biosynthetic pathway optimization of L-cysteine from the DecR regulator variant of Escherichia coli was applied. Through protein engineering, we obtained the DecRN29Y/C81E/M90Q/M99E variant-based biosensor with improved specificity and an 8.71-fold increase in dynamic range. Using the developed biosensor, we performed high-throughput screening of the constructed promoter and RBS combination library, and successfully obtained the optimized strain, which resulted in a 6.29-fold increase in L-cysteine production. Molecular dynamics (MD) simulations and electrophoretic mobility shift analysis (EMSA) showed that the N29Y/C81E/M90Q/M99E variant had enhanced induction activity. This enhancement may be due to the increased binding of the variant to DNA in the presence of L-cysteine, which enhances transcriptional activation. Overall, our biosensor-based strategy provides a promising approach for optimizing biosynthetic pathways at multiple levels. The successful implementation of this strategy demonstrates its potential for screening improved recombinant strains.
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Affiliation(s)
- Zhiyou Zhou
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - Zonglin Li
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - Yahui Zhong
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - Shuai Xu
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - Zhimin Li
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
- Shanghai Collaborative Innovation Center for Biomanufacturing Technology, Shanghai, China
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Cai M, Liu Z, Zhao Z, Wu H, Xu M, Rao Z. Microbial production of L-methionine and its precursors using systems metabolic engineering. Biotechnol Adv 2023; 69:108260. [PMID: 37739275 DOI: 10.1016/j.biotechadv.2023.108260] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 08/11/2023] [Accepted: 09/18/2023] [Indexed: 09/24/2023]
Abstract
L-methionine is an essential amino acid with versatile applications in food, feed, cosmetics and pharmaceuticals. At present, the production of L-methionine mainly relies on chemical synthesis, which conflicts with the concern over serious environmental problems and sustainable development goals. In recent years, microbial production of natural products has been amply rewarded with the emergence and rapid development of system metabolic engineering. However, efficient L-methionine production by microbial fermentation remains a great challenge due to its complicated biosynthetic pathway and strict regulatory mechanism. Additionally, the engineered production of L-methionine precursors, L-homoserine, O-succinyl-L-homoserine (OSH) and O-acetyl-L-homoserine (OAH), has also received widespread attention because they can be catalyzed to L-methionine via a high-efficiently enzymatic reaction in vitro, which is also a promising alternative to chemical route. This review provides a comprehensive overview on the recent advances in the microbial production of L-methionine and its precursors, highlighting the challenges and potential solutions for developing L-methionine microbial cell factories from the perspective of systems metabolic engineering, aiming to offer guidance for future engineering.
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Affiliation(s)
- Mengmeng Cai
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu 214122, China; Yixing Institute of Food and Biotechnology Co., Ltd, Yixing 214200, China
| | - Zhifei Liu
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu 214122, China; Yixing Institute of Food and Biotechnology Co., Ltd, Yixing 214200, China
| | - Zhenqiang Zhao
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu 214122, China; Yixing Institute of Food and Biotechnology Co., Ltd, Yixing 214200, China
| | - Hongxuan Wu
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu 214122, China; Yixing Institute of Food and Biotechnology Co., Ltd, Yixing 214200, China
| | - Meijuan Xu
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu 214122, China; Yixing Institute of Food and Biotechnology Co., Ltd, Yixing 214200, China
| | - Zhiming Rao
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu 214122, China; Yixing Institute of Food and Biotechnology Co., Ltd, Yixing 214200, China.
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3
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Du H, Qi Y, Qiao J, Li L, Xu N, Shao L, Wei L, Liu J. Balancing Redox Homeostasis to Improve l-Cysteine Production in Corynebacterium glutamicum. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2023; 71:13848-13856. [PMID: 37669547 DOI: 10.1021/acs.jafc.3c03828] [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: 09/07/2023]
Abstract
l-Cysteine is a valuable sulfur-containing amino acid with applications across a wide range of fields. Recently, microbial fermentation has emerged as a method to produce l-cysteine. However, cellular redox stress from high levels of l-cysteine is a bottleneck for achieving efficient production. In this study, we aimed to facilitate l-cysteine biosynthesis by modulating cellular redox homeostasis through the introduction of the natural antioxidant astaxanthin in Corynebacterium glutamicum. To achieve this, we first introduced an exogenous astaxanthin synthesis module in C. glutamicum. Then, an l-cysteine-dependent autonomous bifunctional genetic switch was developed to dynamically regulate the l-cysteine and astaxanthin biosynthesis pathway to maintain cellular redox homeostasis. This regulation system achieved high biosynthesis of astaxanthin, which significantly facilitated l-cysteine production. Finally, engineered strain Cg-10 produced 8.45 g/L l-cysteine and 95 mg/L astaxanthin in a 5 L bioreactor, both of which are the highest reported levels in C. glutamicum.
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Affiliation(s)
- Huanmin Du
- Key Laboratory of Engineering Biology for Low-Carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 West seventh Avenue, Tianjin Airport Economic Area, Tianjin 300308, China
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yuting Qi
- Department of Microbiology and Biotechnology, College of Life Sciences, Northeast Agricultural University, No. 600 Changjiang Road, Xiangfang District, Harbin 150030, China
| | - Jinfang Qiao
- College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, China
| | - Lingcong Li
- Key Laboratory of Engineering Biology for Low-Carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 West seventh Avenue, Tianjin Airport Economic Area, Tianjin 300308, China
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ning Xu
- Key Laboratory of Engineering Biology for Low-Carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 West seventh Avenue, Tianjin Airport Economic Area, Tianjin 300308, China
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
| | - Li Shao
- Department of Microbiology and Biotechnology, College of Life Sciences, Northeast Agricultural University, No. 600 Changjiang Road, Xiangfang District, Harbin 150030, China
| | - Liang Wei
- Key Laboratory of Engineering Biology for Low-Carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 West seventh Avenue, Tianjin Airport Economic Area, Tianjin 300308, China
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
| | - Jun Liu
- Key Laboratory of Engineering Biology for Low-Carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 West seventh Avenue, Tianjin Airport Economic Area, Tianjin 300308, China
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
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Chen Z, Lian X, Zhou M, Zhang X, Wang C. Quantitation of L-cystine in Food Supplements and Additives Using 1H qNMR: Method Development and Application. Foods 2023; 12:2421. [PMID: 37372631 DOI: 10.3390/foods12122421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 06/12/2023] [Accepted: 06/16/2023] [Indexed: 06/29/2023] Open
Abstract
Cystine-enriched food supplements are increasingly popular due to their beneficial health effects. However, the lack of industry standards and market regulations resulted in quality issues with cystine food products, including cases of food adulteration and fraud. This study established a reliable and practical method for determining cystine in food supplements and additives using quantitative NMR (qNMR). With the optimized testing solvent, acquisition time, and relaxation delay, the method exhibited higher sensitivity, precision, and reproducibility than the conventional titrimetric method. Additionally, it was more straightforward and more economical than HPLC and LC-MS. Furthermore, the current qNMR method was applied to investigate different food supplements and additives regarding cystine quantity. As a result, four of eight food supplement samples were found to be inaccurately labeled or even with fake labeling, with the relative actual amount of cystine ranging from 0.3% to 107.2%. In comparison, all three food additive samples exhibited satisfactory quality (the relative actual amount of cystine: 97.0-99.9%). Notably, there was no obvious correlation between the quantifiable properties (price and labeled cystine amount) of the tested food supplement samples and their relative actual amount of cystine. The newly developed qNMR-based approach and the subsequent findings might help standardization and regulation of the cystine supplement market.
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Affiliation(s)
- Zhen Chen
- School of Pharmacy, Jiangsu University, Zhenjiang 212013, China
| | - Xiaofang Lian
- Key Laboratory of Marine Drugs, Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao 266003, China
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
| | - Meichen Zhou
- Key Laboratory of Marine Drugs, Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao 266003, China
| | - Xiuli Zhang
- Key Laboratory of Marine Drugs, Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao 266003, China
- Laboratory for Marine Drugs and Bioproducts of Qingdao Pilot National Laboratory for Marine Science and Technology, Qingdao 266237, China
| | - Cong Wang
- Key Laboratory of Marine Drugs, Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao 266003, China
- Laboratory for Marine Drugs and Bioproducts of Qingdao Pilot National Laboratory for Marine Science and Technology, Qingdao 266237, China
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Yin X, Zhou Y, Yang H, Liao Y, Ma T, Wang F. Enhanced selenocysteine biosynthesis for seleno-methylselenocysteine production in Bacillus subtilis. Appl Microbiol Biotechnol 2023; 107:2843-2854. [PMID: 36941436 DOI: 10.1007/s00253-023-12482-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Revised: 02/10/2023] [Accepted: 03/12/2023] [Indexed: 03/23/2023]
Abstract
Seleno-methylselenocysteine (SeMCys) is an effective component for selenium supplementation with anti-carcinogenic potential and can ameliorate neuropathology and cognitive deficits. In this study, we aimed to engineer Bacillus subtilis 168 for the microbial production of SeMCys. First, the accumulation of intracellular selenocysteine (SeCys) as the precursor of SeMCys was enhanced through overexpression of serine O-acetyltransferase, which was desensitized against feedback inhibition by cysteine. Next, the S-adenosylmethionine (SAM) synthetic pathway was optimized to improve methyl donor availability through expression of S-adenosylmethionine synthetase. Further, SeMCys was successfully produced through expression of the selenocysteine methyltransferase in SeCys and SAM-producing strain. The increased expression level of selenocysteine methyltransferase benefited the SeMCys production. Finally, all the heterologous genes were integrated into the genome of B. subtilis, and the strain produced SeMCys at a titer of 18.4 μg/L in fed-batch culture. This is the first report on the metabolic engineering of B. subtilis for microbial production of SeMCys and provides a good starting point for future pathway engineering to achieve the industrial-grade production of SeMCys. KEY POINTS: • Expression of the feedback-insensitive serine O-acetyltransferase provided B. subtilis the ability of accumulating SeCys. • SAM production was enhanced through expressing S-adenosylmethionine synthetase in B. subtilis. • Expression of selenocysteine methyltransferase in SeCys and SAM-accumulating strain facilitated SeMCys production.
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Affiliation(s)
- Xian Yin
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, Beijing Technology and Business University, Fucheng RD 11, Beijing, 100048, China
- School of Light Industry, Beijing Technology and Business University, Fucheng RD 11, Beijing, 100048, China
| | - Yu Zhou
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, Beijing Technology and Business University, Fucheng RD 11, Beijing, 100048, China
- School of Light Industry, Beijing Technology and Business University, Fucheng RD 11, Beijing, 100048, China
| | - Hulin Yang
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, Beijing Technology and Business University, Fucheng RD 11, Beijing, 100048, China
- School of Light Industry, Beijing Technology and Business University, Fucheng RD 11, Beijing, 100048, China
| | - Yonghong Liao
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, Beijing Technology and Business University, Fucheng RD 11, Beijing, 100048, China
- School of Light Industry, Beijing Technology and Business University, Fucheng RD 11, Beijing, 100048, China
| | - Tengbo Ma
- Biological Defense Department, Institute of Chemical Defence, Zhongxin RD 1, Beijing, 102205, China
| | - Fenghuan Wang
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, Beijing Technology and Business University, Fucheng RD 11, Beijing, 100048, China.
- School of Light Industry, Beijing Technology and Business University, Fucheng RD 11, Beijing, 100048, China.
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Qin X, Yang C, Guo Y, Liu J, Bitter JH, Scott EL, Zhang C. Effect of ultrasound on keratin valorization from chicken feather waste: Process optimization and keratin characterization. ULTRASONICS SONOCHEMISTRY 2023; 93:106297. [PMID: 36641870 PMCID: PMC9860336 DOI: 10.1016/j.ultsonch.2023.106297] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 01/01/2023] [Accepted: 01/08/2023] [Indexed: 06/17/2023]
Abstract
Chicken feather (CF) has been deemed as one of the main poultry byproducts with a large amount produced globally. However, the robust chemical nature of chicken feathers has been limiting in its wide-scale utilization and valorization. The study proposed a strategy of keratin regeneration from chicken feather combining ultrasound and Cysteine (Cys)-reduction for keratin regeneration. First, the ultrasonic effect on feather degradation and keratin properties was systematically explored based on Cys-reduction. Results showed that the feather dissolution was significantly improved by increasing both ultrasonic time and power, and the former had a greater impact on keratin yield. However, the treatment time over 4 h led to a decrease of keratin yield, producing more soluble peptides, > 9.7 % of which were < 0.5 kDa. Meanwhile, prolonging time decreased the thermal stability with weight loss at a lower temperature and amino acids content (e.g., Ser, Pro and Gly) of keratin. Conversely, no remarkable damage in chemical structure and thermal stability of regenerated keratin was observed by only increasing ultrasonic power, while the keratin solubility was notably promoted and reached 745.72 mg·g-1 in NaOH (0.1 M) solution (400 W, 4 h). The regenerated keratin under optimal conditions (130 W, 2.7 h, and 15 % of Cys) possessed better solubility while without obvious damage in chemical structure, thermal stability, and amino acids composition. The study illustrated that ultrasound physically improved CF degradation and keratin solubility without nature damage and provided an alternative for keratin regeneration involving no toxic reagent, probably holding promise in the utilization and valorization of feather waste.
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Affiliation(s)
- Xiaojie Qin
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing 100193, China
- Biobased Chemistry and Technology, Wageningen University and Research, Wageningen 6700AA, Netherlands
| | - Chuan Yang
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Yujie Guo
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing 100193, China
- Xinjiang Taikun Group Co. Ltd, Xinjiang Uygur Autonomous Region, Changji 831100, China
| | - Jiqian Liu
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Johannes H. Bitter
- Biobased Chemistry and Technology, Wageningen University and Research, Wageningen 6700AA, Netherlands
| | - Elinor L. Scott
- Biobased Chemistry and Technology, Wageningen University and Research, Wageningen 6700AA, Netherlands
| | - Chunhui Zhang
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing 100193, China
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7
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Kong G, Yang Y, Luo Y, Liu F, Song D, Sun G, Li D, Guo J, Dong M, Xu M. Cysteine-Mediated Extracellular Electron Transfer of Lysinibacillus varians GY32. Microbiol Spectr 2022; 10:e0279822. [PMID: 36318024 PMCID: PMC9769522 DOI: 10.1128/spectrum.02798-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Accepted: 10/04/2022] [Indexed: 11/06/2022] Open
Abstract
Microbial extracellular electron transfer (EET) is essential in many natural and engineering processes. Compared with the versatile EET pathways of Gram-negative bacteria, the EET of Gram-positive bacteria has been studied much less and is mainly limited to the flavin-mediated pathway. Here, we investigate the EET pathway of a Gram-positive filamentous bacterium Lysinibacillus varians GY32. Strain GY32 has a wide electron donor spectrum (including lactate, acetate, formate, and some amino acids) in electrode respiration. Transcriptomic, proteomic, and electrochemical analyses show that the electrode respiration of GY32 mainly depends on electron mediators, and c-type cytochromes may be involved in its respiration. Fluorescent sensor and electrochemical analyses demonstrate that strain GY32 can secrete cysteine and flavins. Cysteine added shortly after inoculation into microbial fuel cells accelerated EET, showing cysteine is a new endogenous electron mediator of Gram-positive bacteria, which provides novel information to understand the EET networks in natural environments. IMPORTANCE Extracellular electron transport (EET) is a key driving force in biogeochemical element cycles and microbial chemical-electrical-optical energy conversion on the Earth. Gram-positive bacteria are ubiquitous and even dominant in EET-enriched environments. However, attention and knowledge of their EET pathways are largely lacking. Gram-positive bacterium Lysinibacillus varians GY32 has extremely long cells (>1 mm) and conductive nanowires, promising a unique and enormous role in the microenvironments where it lives. Its capability to secrete cysteine renders it not only an EET pathway to respire and survive, but also an electrochemical strategy to connect and shape the ambient microbial community at a millimeter scale. Moreover, its incapability of using flavins as an electron mediator suggests that the common electron mediator is species-dependent. Therefore, our results are important to understanding the EET networks in natural and engineering processes.
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Affiliation(s)
- Guannan Kong
- Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China
| | - Yonggang Yang
- Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China
| | - Yeshen Luo
- Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China
| | - Fei Liu
- Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China
| | - Da Song
- Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China
| | - Guoping Sun
- Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China
| | - Daobo Li
- Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China
| | - Jun Guo
- Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China
| | - Meijun Dong
- Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China
| | - Meiying Xu
- Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China
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Usuda Y, Nishio Y, Nonaka G, Hara Y. Microbial Production Potential of Pantoea ananatis: From Amino Acids to Secondary Metabolites. Microorganisms 2022; 10:microorganisms10061133. [PMID: 35744651 PMCID: PMC9231021 DOI: 10.3390/microorganisms10061133] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 05/25/2022] [Accepted: 05/27/2022] [Indexed: 11/16/2022] Open
Abstract
Pantoea ananatis, a gram-negative bacterium belonging to the Erwiniaceae family, is a well-known phytopathogen isolated from many ecological niches and plant hosts. However, this bacterium also provides us with various beneficial characteristics, such as the growth promotion of their host plants and increased crop yield. Some isolated non-pathogenic strains are promising for the microbial production of useful substances. P. ananatis AJ13355 was isolated as an acidophilic bacterium and was used as an excellent host to produce L-glutamic acid under acidic conditions. The genome sequence of P. ananatis AJ13355 was determined, and specific genome-engineering technologies were developed. As a result, P. ananatis was successfully used to construct a bacterial strain that produces cysteine, a sulfur-containing amino acid that has been difficult to produce through fermentation because of complex regulation. Furthermore, by heterologous expression including plant-derived genes, construction of a strain that produces isoprenoids such as isoprene and linalool as secondary metabolites was achieved. P. ananatis is shown to be a useful host for the production of secondary metabolites, as well as amino acids, and is expected to be used as a platform for microbial production of bioactive substances, aromatic substances, and other high-value-added substances of plant origin in the future.
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Affiliation(s)
- Yoshihiro Usuda
- Research and Business Planning Department, Ajinomoto Co., Inc., Tokyo 104-8315, Japan
- Correspondence: ; Tel.: +81-70-4361-3762; Fax: +81-3-5250-8352
| | - Yousuke Nishio
- Research Institute for Bioscience Products & Fine Chemicals, Ajinomoto Co., Inc., Kawasaki 210-8681, Japan; (Y.N.); (Y.H.)
| | - Gen Nonaka
- Ajinomoto-Genetika Research Institute, Moscow 117545, Russia;
| | - Yoshihiko Hara
- Research Institute for Bioscience Products & Fine Chemicals, Ajinomoto Co., Inc., Kawasaki 210-8681, Japan; (Y.N.); (Y.H.)
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A novel rosamine-based fluorescent probe for the rapid and selective detection of cysteine in BSA, water, milk, cabbage, radish, apple, and pear. Food Chem 2021; 356:129658. [PMID: 33838604 DOI: 10.1016/j.foodchem.2021.129658] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 01/21/2021] [Accepted: 03/16/2021] [Indexed: 01/25/2023]
Abstract
A novel fluorescent probe (RA), based on the rosamine skeleton bearing acrylate group, has been reasonably designed and prepared, which employed an addition-cyclization-elimination sequence reaction mechanism to detect cysteine. RA displayed rapid response to cysteine within 1.5 min, and exhibited satisfactory selectivity for cysteine over H2S, glutathione (Glu), and homocysteine (Hcy), due to the formation of seven-membered lactam favored kinetically. Fluorescence ratio was utilized to detect cysteine from 6.0 to 20.0 μM with a detection limit of 0.29 μM. More, RA was used to monitor cysteine in BSA, water, milk, milk powder, cabbage, radish, apple, and pear.
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10
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Gallardo-Benavente C, Campo-Giraldo JL, Castro-Severyn J, Quiroz A, Pérez-Donoso JM. Genomics Insights into Pseudomonas sp. CG01: An Antarctic Cadmium-Resistant Strain Capable of Biosynthesizing CdS Nanoparticles Using Methionine as S-Source. Genes (Basel) 2021; 12:187. [PMID: 33514061 PMCID: PMC7912247 DOI: 10.3390/genes12020187] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2020] [Revised: 01/20/2021] [Accepted: 01/22/2021] [Indexed: 12/23/2022] Open
Abstract
Here, we present the draft genome sequence of Pseudomonas sp. GC01, a cadmium-resistant Antarctic bacterium capable of biosynthesizing CdS fluorescent nanoparticles (quantum dots, QDs) employing a unique mechanism involving the production of methanethiol (MeSH) from methionine (Met). To explore the molecular/metabolic components involved in QDs biosynthesis, we conducted a comparative genomic analysis, searching for the genes related to cadmium resistance and sulfur metabolic pathways. The genome of Pseudomonas sp. GC01 has a 4,706,645 bp size with a 58.61% G+C content. Pseudomonas sp. GC01 possesses five genes related to cadmium transport/resistance, with three P-type ATPases (cadA, zntA, and pbrA) involved in Cd-secretion that could contribute to the extracellular biosynthesis of CdS QDs. Furthermore, it exhibits genes involved in sulfate assimilation, cysteine/methionine synthesis, and volatile sulfur compounds catabolic pathways. Regarding MeSH production from Met, Pseudomonas sp. GC01 lacks the genes E4.4.1.11 and megL for MeSH generation. Interestingly, despite the absence of these genes, Pseudomonas sp. GC01 produces high levels of MeSH. This is probably associated with the metC gene that also produces MeSH from Met in bacteria. This work is the first report of the potential genes involved in Cd resistance, sulfur metabolism, and the process of MeSH-dependent CdS QDs bioproduction in Pseudomonas spp. strains.
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Affiliation(s)
- Carla Gallardo-Benavente
- Programa de Doctorado en Ciencias de Recursos Naturales, Universidad de La Frontera, 4780000 Temuco, Chile;
- Centro de Excelencia en Investigación Biotecnológica Aplicada al Medio Ambiente (CIBAMA), Facultad de Ingeniería y Ciencias, Universidad de La Frontera, 4780000 Temuco, Chile
| | - Jessica L. Campo-Giraldo
- BioNanotechnology and Microbiology Lab, Center for Bioinformatics and Integrative Biology, Facultad de Ciencias de la Vida, Universidad Andres Bello, 8320000 Santiago, Chile;
| | - Juan Castro-Severyn
- Laboratorio de Microbiología Aplicada y Extremófilos, Facultad de Ingeniería y Ciencias Geológicas, Universidad Católica del Norte, 1240000 Antofagasta, Chile;
| | - Andrés Quiroz
- Centro de Excelencia en Investigación Biotecnológica Aplicada al Medio Ambiente (CIBAMA), Facultad de Ingeniería y Ciencias, Universidad de La Frontera, 4780000 Temuco, Chile
- Departamento de Ciencias Químicas y Recursos Naturales, Facultad de Ingeniería y Ciencias, Universidad de La Frontera, 4780000 Temuco, Chile
| | - José M. Pérez-Donoso
- BioNanotechnology and Microbiology Lab, Center for Bioinformatics and Integrative Biology, Facultad de Ciencias de la Vida, Universidad Andres Bello, 8320000 Santiago, Chile;
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Sagong HY, Kim B, Joo S, Kim KJ. Structural and Functional Characterization of Cystathionine γ-lyase from Bacillus cereus ATCC 14579. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2020; 68:15267-15274. [PMID: 33301683 DOI: 10.1021/acs.jafc.0c06503] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Cysteine is a semiessential amino acid and plays an important role in metabolism and protein structure and has also been applied in various industrial fields, such as pharmaceutical, food, cosmetic, and animal feed industries. Metabolic engineering studies have been conducted for the cysteine production through bacterial fermentation, but studies on the cysteine biosynthetic pathway in microorganisms are limited. We report the biochemical characteristics of cystathionine γ-lyase from Bacillus cereus ATCC 14579 (BcCGL). We also determined the crystal structure of BcCGL in complex with the PLP cofactor and identified the substrate binding mode. We observed that the replacement of the conserved Glu321 residue to alanine showed increased activity by providing wider active site entrance and hydrophobic interaction for the substrate. We suggest that the structural differences of the α13-α14 region in CGL enzymes might determine the active site conformation.
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Affiliation(s)
- Hye-Young Sagong
- School of Life Sciences, KNU Creative BioResearch Group, Kyungpook National University, Daegu 41566, Republic of Korea
- KNU Institute for Microorganisms, Kyungpook National University, Daegu 41566, Republic of Korea
| | - Bongsang Kim
- School of Life Sciences, KNU Creative BioResearch Group, Kyungpook National University, Daegu 41566, Republic of Korea
- KNU Institute for Microorganisms, Kyungpook National University, Daegu 41566, Republic of Korea
| | - Seongjoon Joo
- School of Life Sciences, KNU Creative BioResearch Group, Kyungpook National University, Daegu 41566, Republic of Korea
- KNU Institute for Microorganisms, Kyungpook National University, Daegu 41566, Republic of Korea
| | - Kyung-Jin Kim
- School of Life Sciences, KNU Creative BioResearch Group, Kyungpook National University, Daegu 41566, Republic of Korea
- KNU Institute for Microorganisms, Kyungpook National University, Daegu 41566, Republic of Korea
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12
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Tanaka Y, Yoshikaie K, Takeuchi A, Ichikawa M, Mori T, Uchino S, Sugano Y, Hakoshima T, Takagi H, Nonaka G, Tsukazaki T. Crystal structure of a YeeE/YedE family protein engaged in thiosulfate uptake. SCIENCE ADVANCES 2020; 6:eaba7637. [PMID: 32923628 PMCID: PMC7449682 DOI: 10.1126/sciadv.aba7637] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Accepted: 07/13/2020] [Indexed: 05/04/2023]
Abstract
We have demonstrated that a bacterial membrane protein, YeeE, mediates thiosulfate uptake. Thiosulfate is used for cysteine synthesis in bacteria as an inorganic sulfur source in the global biological sulfur cycle. The crystal structure of YeeE at 2.5-Å resolution reveals an unprecedented hourglass-like architecture with thiosulfate in the positively charged outer concave side. YeeE is composed of loops and 13 helices including 9 transmembrane α helices, most of which show an intramolecular pseudo 222 symmetry. Four characteristic loops are buried toward the center of YeeE and form its central region surrounded by the nine helices. Additional electron density maps and successive molecular dynamics simulations imply that thiosulfate can remain temporally at several positions in the proposed pathway. We propose a plausible mechanism of thiosulfate uptake via three important conserved cysteine residues of the loops along the pathway.
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Affiliation(s)
- Yoshiki Tanaka
- Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan
| | | | - Azusa Takeuchi
- Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan
| | | | - Tomoyuki Mori
- Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan
- Institute for Quantitative Biosciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Sayaka Uchino
- Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan
| | - Yasunori Sugano
- Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan
| | - Toshio Hakoshima
- Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan
| | - Hiroshi Takagi
- Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan
| | - Gen Nonaka
- Ajinomoto-Genetika Research Institute, Moscow 117545, Russia
- Research Institute for Bioscience Products and Fine Chemicals, Ajinomoto Co. Inc., Kawasaki 210-8681, Japan
| | - Tomoya Tsukazaki
- Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan
- Corresponding author.
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Onyeabor M, Martinez R, Kurgan G, Wang X. Engineering transport systems for microbial production. ADVANCES IN APPLIED MICROBIOLOGY 2020; 111:33-87. [PMID: 32446412 DOI: 10.1016/bs.aambs.2020.01.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The rapid development in the field of metabolic engineering has enabled complex modifications of metabolic pathways to generate a diverse product portfolio. Manipulating substrate uptake and product export is an important research area in metabolic engineering. Optimization of transport systems has the potential to enhance microbial production of renewable fuels and chemicals. This chapter comprehensively reviews the transport systems critical for microbial production as well as current genetic engineering strategies to improve transport functions and thus production metrics. In addition, this chapter highlights recent advancements in engineering microbial efflux systems to enhance cellular tolerance to industrially relevant chemical stress. Lastly, future directions to address current technological gaps are discussed.
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Affiliation(s)
- Moses Onyeabor
- School of Life Sciences, Arizona State University, Tempe, AZ, United States
| | - Rodrigo Martinez
- School of Life Sciences, Arizona State University, Tempe, AZ, United States
| | - Gavin Kurgan
- School of Life Sciences, Arizona State University, Tempe, AZ, United States
| | - Xuan Wang
- School of Life Sciences, Arizona State University, Tempe, AZ, United States.
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14
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Liu W, Zhu X, Lian J, Huang L, Xu Z. Efficient production of glutathione with multi-pathway engineering in Corynebacterium glutamicum. J Ind Microbiol Biotechnol 2019; 46:1685-1695. [PMID: 31420796 DOI: 10.1007/s10295-019-02220-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2019] [Accepted: 07/11/2019] [Indexed: 01/15/2023]
Abstract
Glutathione is a bioactive tripeptide composed of glycine, L-cysteine, and L-glutamate, and has been widely used in pharmaceutical, food, and healthy products. The current metabolic studies of glutathione were mainly focused on the native producing strains with precursor amino acid supplementation. In the present work, Corynebacterium glutamicum, a workhorse for industrial production of a series of amino acids, was engineered to produce glutathione. First, the introduction of glutathione synthetase gene gshF from Streptococcus agalactiae fulfilled the ability of glutathione production in C. glutamicum and revealed that L-cysteine was the limiting factor. Then, considering the inherent capability of L-glutamate synthesis and the availability of external addition of low-cost glycine, L-cysteine biosynthesis was enhanced using a varieties of pathway engineering methods, such as disrupting the degradation pathways of L-cysteine and L-serine, and removing the repressor responsible for sulfur metabolism. Finally, the simultaneously introduction of gshF and enhancement of cysteine formation enabled C. glutamicum strain to produce glutathione greatly. Without external addition of L-cysteine and L-glutamate, 756 mg/L glutathione was produced. This is first time to demonstrate the potential of the glutathione non-producing strain C. glutamicum for glutathione production and provide a novel strategy to construct glutathione-producing strains.
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Affiliation(s)
- Wei Liu
- Key Laboratory of Biomass Chemical Engineering (Education Ministry), College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027, China.,College of Chemical and Biological Engineering, Institute of Biological Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Xiangcheng Zhu
- Xiangya International Academy of Translational Medicine, Central South University, Changsha, 410013, Hunan, China.
| | - Jiazhang Lian
- Key Laboratory of Biomass Chemical Engineering (Education Ministry), College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027, China.,College of Chemical and Biological Engineering, Institute of Biological Engineering, Zhejiang University, Hangzhou, 310027, China.,Center for Synthetic Biology, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Lei Huang
- Key Laboratory of Biomass Chemical Engineering (Education Ministry), College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027, China.,College of Chemical and Biological Engineering, Institute of Biological Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Zhinan Xu
- Key Laboratory of Biomass Chemical Engineering (Education Ministry), College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027, China. .,College of Chemical and Biological Engineering, Institute of Biological Engineering, Zhejiang University, Hangzhou, 310027, China. .,Center for Synthetic Biology, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027, China.
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15
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Wu F, Cai D, Li L, Li Y, Yang H, Li J, Ma X, Chen S. Modular metabolic engineering of lysine supply for enhanced production of bacitracin in Bacillus licheniformis. Appl Microbiol Biotechnol 2019; 103:8799-8812. [DOI: 10.1007/s00253-019-10110-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 08/12/2019] [Accepted: 08/28/2019] [Indexed: 02/06/2023]
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16
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Development of a new fluorescent probe for cysteine detection in processed food samples. Anal Bioanal Chem 2019; 411:6203-6212. [PMID: 31300856 DOI: 10.1007/s00216-019-02012-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Revised: 06/15/2019] [Accepted: 07/01/2019] [Indexed: 10/26/2022]
Abstract
Cysteine is a crucial amino acid, found in a huge amount in protein-rich foods. We focused our research to determine the amount of free cysteine consumed highly in foods such as pork, beef, poultry, eggs, dairy, red peppers, soybeans, broccoli, brussels sprouts, oats, and wheat germs. A newly designed carbazole-pyridine-based fluorescent probe (CPI) has been introduced for quantitative estimation of cysteine (Cys) with a "turn on" fluorescence in some popular processed food samples chosen from our daily diet. CPI shows both naked eye and UV-visible color changes upon interaction with cysteine. The binding approach between CPI and Cys at biological pH has been thoroughly explored by UV-visible and fluorescence spectroscopy. From Job's plot analysis, 1:1 stoichiometric reaction between CPI and Cys is observed with a detection limit of 3.8 μM. NMR, ESI mass spectrometry, and time-dependent density functional theory (TD-DFT) study enlightens the formation of more stable product CPI-Cys. The "turn on" response of the probe CPI occurs due to the interruption of intra-molecular charge transfer (ICT) process upon reacting with cysteine. Moreover, CPI is a very stable, cost-effective compound and exhibits excellent real-time selectivity towards Cys over all other comparative biorelevant analytes. Interestingly, our proposed method is much advantageous as it is able to estimate cysteine predominantly by screening out other comparative biocomponents found in different protein-rich foods.
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Wei L, Wang H, Xu N, Zhou W, Ju J, Liu J, Ma Y. Metabolic engineering of Corynebacterium glutamicum for l-cysteine production. Appl Microbiol Biotechnol 2018; 103:1325-1338. [DOI: 10.1007/s00253-018-9547-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 11/26/2018] [Accepted: 11/28/2018] [Indexed: 10/27/2022]
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18
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Wang J, Wang H, Hao Y, Yang S, Tian H, Sun B, Liu Y. A novel reaction-based fluorescent probe for the detection of cysteine in milk and water samples. Food Chem 2018; 262:67-71. [DOI: 10.1016/j.foodchem.2018.04.084] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Revised: 04/05/2018] [Accepted: 04/21/2018] [Indexed: 01/01/2023]
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Graf M, Zieringer J, Haas T, Nieß A, Blombach B, Takors R. Physiological Response of Corynebacterium glutamicum to Increasingly Nutrient-Rich Growth Conditions. Front Microbiol 2018; 9:2058. [PMID: 30210489 PMCID: PMC6123352 DOI: 10.3389/fmicb.2018.02058] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Accepted: 08/13/2018] [Indexed: 01/31/2023] Open
Abstract
To ensure economic competitiveness, bioprocesses should achieve maximum productivities enabled by high growth rates (μ) and equally high substrate consumption rates (qS) as a prerequisite of sufficient carbon-to-product conversion. Both traits were investigated and improved via bioprocess engineering approaches studying the industrial work horse Corynebacterium glutamicum. Standard minimal medium CGXII with glucose as sole carbon source was supplemented with complex brain-heart-infusion (BHI) or amino acid (AA) cocktails. Maximum μ of 0.67 h-1 was exclusively observed in 37 g BHI L-1 whereas only minor growth stimulation was found after AA supplementation (μ = 0.468 h-1). Increasing glucose consumption rates (qGlc) were solely observed in certain dosages of BHI (1-10 g L-1), while 37 g BHI L-1 and AA addition revealed qGlc below the reference experiments. Moreover, BHI supplementation revealed Monod-type saturation kinetics of μ (KBHI = 2.73 g BHI L-1) referring to the preference of non-AAs as key boosting nutrients. ATP-demands under reference, 1 g BHI L-1, and AA conditions were nearly constant but halved in BHI concentrations above 5 g L-1 reflecting the energetic advantage of consuming complex nutrient components in addition to "simple" building blocks such as AAs. Furthermore, C. glutamicum revealed maximum biomass per carbon yields of about 18 gCDW C-mol-1 irrespective of the medium. In AA supplementation experiments, simultaneous uptake of 17 AAs was observed, maximum individual consumption rates determined, and L-asparagine and L-glutamine were distinguished as compounds with the highest consumption rates. Employment of the expanded stoichiometric model iMG481 successfully reproduced experimental results and revealed the importance of C. glutamicum's transaminase network to compensate needs of limiting AA supply. Model-based sensitivity studies attributed the highest impact on μ to AAs with high ATP and NADPH demands such as L-tryptophan or L-phenylalanine.
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Affiliation(s)
| | | | | | | | | | - Ralf Takors
- Institute of Biochemical Engineering, University of Stuttgart, Stuttgart, Germany
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20
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Kallscheuer N. Engineered Microorganisms for the Production of Food Additives Approved by the European Union-A Systematic Analysis. Front Microbiol 2018; 9:1746. [PMID: 30123195 PMCID: PMC6085563 DOI: 10.3389/fmicb.2018.01746] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Accepted: 07/12/2018] [Indexed: 01/16/2023] Open
Abstract
In the 1950s, the idea of a single harmonized list of food additives for the European Union arose. Already in 1962, the E-classification system, a robust food safety system intended to protect consumers from possible food-related risks, was introduced. Initially, it was restricted to colorants, but at later stages also preservatives, antioxidants, emulsifiers, stabilizers, thickeners, gelling agents, sweeteners, and flavorings were included. Currently, the list of substances authorized by the European Food Safety Authority (EFSA) (referred to as "E numbers") comprises 316 natural or artificial substances including small organic molecules, metals, salts, but also more complex compounds such as plant extracts and polymers. Low overall concentrations of such compounds in natural producers due to inherent regulation mechanisms or production processes based on non-regenerative carbon sources led to an increasing interest in establishing more reliable and sustainable production platforms. In this context, microorganisms have received significant attention as alternative sources providing access to these compounds. Scientific advancements in the fields of molecular biology and genetic engineering opened the door toward using engineered microorganisms for overproduction of metabolites of their carbon metabolism such as carboxylic acids and amino acids. In addition, entire pathways, e.g., of plant origin, were functionally introduced into microorganisms, which holds the promise to get access to an even broader range of accessible products. The aim of this review article is to give a systematic overview on current efforts during construction and application of microbial cell factories for the production of food additives listed in the EU "E numbers" catalog. The review is focused on metabolic engineering strategies of industrially relevant production hosts also discussing current bottlenecks in the underlying metabolic pathways and how they can be addressed in the future.
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Affiliation(s)
- Nicolai Kallscheuer
- Institute of Bio- and Geosciences, IBG-1: Biotechnology, Forschungszentrum Jülich GmbH, Jülich, Germany
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21
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Kawano Y, Suzuki K, Ohtsu I. Current understanding of sulfur assimilation metabolism to biosynthesize L-cysteine and recent progress of its fermentative overproduction in microorganisms. Appl Microbiol Biotechnol 2018; 102:8203-8211. [PMID: 30046857 DOI: 10.1007/s00253-018-9246-4] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 07/12/2018] [Accepted: 07/13/2018] [Indexed: 12/01/2022]
Abstract
To all organisms, sulfur is an essential and important element. The assimilation of inorganic sulfur molecules such as sulfate and thiosulfate into organic sulfur compounds such as L-cysteine and L-methionine (essential amino acid for human) is largely contributed by microorganisms. Of these, special attention is given to thiosulfate (S2O32-) assimilation, because thiosulfate relative to often utilized sulfate (SO42-) as a sulfur source is proposed to be more advantageous in microbial growth and biotechnological applications like L-cysteine fermentative overproduction toward industrial manufacturing. In Escherichia coli as well as other many bacteria, the thiosulfate assimilation pathway is known to depend on O-acetyl-L-serine sulfhydrylase B. Recently, another yet-unidentified CysM-independent thiosulfate pathway was found in E. coli. This pathway is expected to consist of the initial part of the thiosulfate to sulfite (SO32-) conversion, and the latter part might be shared with the final part of the known sulfate assimilation pathway [sulfite → sulfide (S2-) → L-cysteine]. The catalysis of thiosulfate to sulfite is at least partly mediated by thiosulfate sulfurtransferase (GlpE). In this mini-review, we introduce updated comprehensive information about sulfur assimilation in microorganisms, including this topic. Also, we introduce recent advances of the application study about L-cysteine overproduction, including the GlpE overexpression.
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Affiliation(s)
- Yusuke Kawano
- Innovation Medical Research Institute, University of Tsukuba, Tsukuba, Japan
| | - Kengo Suzuki
- Department of Research and Development, Euglena Co., Ltd., Minato-ku, Tokyo, Japan
| | - Iwao Ohtsu
- Innovation Medical Research Institute, University of Tsukuba, Tsukuba, Japan.
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22
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Yeon JY, Yoo SJ, Takagi H, Kang HA. A Novel Mitochondrial Serine O-Acetyltransferase, OpSAT1, Plays a Critical Role in Sulfur Metabolism in the Thermotolerant Methylotrophic Yeast Ogataea parapolymorpha. Sci Rep 2018; 8:2377. [PMID: 29402922 PMCID: PMC5799214 DOI: 10.1038/s41598-018-20630-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 01/22/2018] [Indexed: 12/03/2022] Open
Abstract
In most bacteria and plants, direct biosynthesis of cysteine from sulfide via O-acetylserine (OAS) is essential to produce sulfur amino acids from inorganic sulfur. Here, we report the functional analysis of a novel mitochondrial serine O-acetyltransferase (SAT), responsible for converting serine into OAS, in the thermotolerant methylotrophic yeast Ogataea parapolymorpha. Domain analysis of O. parapolymorpha SAT (OpSat1p) and other fungal SATs revealed that these proteins possess a mitochondrial targeting sequence (MTS) at the N-terminus and an α/β hydrolase 1 domain at the C-terminal region, which is quite different from the classical SATs of bacteria and plants. Noticeably, OpSat1p is functionally interchangeable with Escherichia coli SAT, CysE, despite that it displays much less enzymatic activity, with marginal feedback inhibition by cysteine, compared to CysE. The Opsat1Δ-null mutant showed remarkably reduced intracellular levels of cysteine and glutathione, implying OAS generation defect. The MTS of OpSat1p directs the mitochondrial targeting of a reporter protein, thus, supporting the localization of OpSat1p in the mitochondria. Intriguingly, the OpSat1p variant lacking MTS restores the OAS auxotrophy, but not the cysteine auxotrophy of the Opsat1Δ mutant strain. This is the first study on a mitochondrial SAT with critical function in sulfur assimilatory metabolism in fungal species.
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Affiliation(s)
- Ji Yoon Yeon
- Department of Life Science, Chung-Ang University, Seoul, 06974, Korea
| | - Su Jin Yoo
- Department of Life Science, Chung-Ang University, Seoul, 06974, Korea
| | - Hiroshi Takagi
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Nara, 630-0192, Japan.
| | - Hyun Ah Kang
- Department of Life Science, Chung-Ang University, Seoul, 06974, Korea.
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Nonaka G, Takumi K. Cysteine degradation gene yhaM, encoding cysteine desulfidase, serves as a genetic engineering target to improve cysteine production in Escherichia coli. AMB Express 2017; 7:90. [PMID: 28488255 PMCID: PMC5423876 DOI: 10.1186/s13568-017-0389-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Accepted: 04/21/2017] [Indexed: 11/16/2022] Open
Abstract
Cysteine is an important amino acid for various industries; however, there is no efficient microbial fermentation-based production method available. Owing to its cytotoxicity, bacterial intracellular levels of cysteine are stringently controlled via several modes of regulation, including cysteine degradation by cysteine desulfhydrases and cysteine desulfidases. In Escherichia coli, several metabolic enzymes are known to exhibit cysteine degradative activities, however, their specificity and physiological significance for cysteine detoxification via degradation are unclear. Relaxing the strict regulation of cysteine is crucial for its overproduction; therefore, identifying and modulating the major degradative activity could facilitate the genetic engineering of a cysteine-producing strain. In the present study, we used genetic screening to identify genes that confer cysteine resistance in E. coli and we identified yhaM, which encodes cysteine desulfidase and decomposes cysteine into hydrogen sulfide, pyruvate, and ammonium. Phenotypic characterization of a yhaM mutant via growth under toxic concentrations of cysteine followed by transcriptional analysis of its response to cysteine showed that yhaM is cysteine-inducible, and its physiological role is associated with resisting the deleterious effects of cysteine in E. coli. In addition, we confirmed the effects of this gene on the fermentative production of cysteine using E. coli-based cysteine-producing strains. We propose that yhaM encodes the major cysteine-degrading enzyme and it has the most significant role in cysteine detoxification among the numerous enzymes reported in E. coli, thereby providing a core target for genetic engineering to improve cysteine production in this bacterium.
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Joo YC, Hyeon JE, Han SO. Metabolic Design of Corynebacterium glutamicum for Production of l-Cysteine with Consideration of Sulfur-Supplemented Animal Feed. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2017; 65:4698-4707. [PMID: 28560868 DOI: 10.1021/acs.jafc.7b01061] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
l-Cysteine is a valuable sulfur-containing amino acid widely used as a nutrition supplement in industrial food production, agriculture, and animal feed. However, this amino acid is mostly produced by acid hydrolysis and extraction from human or animal hairs. In this study, we constructed recombinant Corynebacterium glutamicum strains that overexpress combinatorial genes for l-cysteine production. The aims of this work were to investigate the effect of the combined overexpression of serine acetyltransferase (CysE), O-acetylserine sulfhydrylase (CysK), and the transcriptional regulator CysR on l-cysteine production. The CysR-overexpressing strain accumulated approximately 2.7-fold more intracellular sulfide than the control strain (empty pMT-tac vector). Moreover, in the resulting CysEKR recombinant strain, combinatorial overexpression of genes involved in l-cysteine production successfully enhanced its production by approximately 3.0-fold relative to that in the control strain. This study demonstrates a biotechnological model for the production of animal feed supplements such as l-cysteine using metabolically engineered C. glutamicum.
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Affiliation(s)
- Young-Chul Joo
- Department of Biotechnology, Korea University , Seoul 02841, Republic of Korea
| | - Jeong Eun Hyeon
- Department of Biotechnology, Korea University , Seoul 02841, Republic of Korea
- Department of Chemical and Biomolecular Engineering, University of Delaware , Newark, Delaware 19702, United States
| | - Sung Ok Han
- Department of Biotechnology, Korea University , Seoul 02841, Republic of Korea
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Fermentative Production of Cysteine by Pantoea ananatis. Appl Environ Microbiol 2017; 83:AEM.02502-16. [PMID: 28003193 DOI: 10.1128/aem.02502-16] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Accepted: 12/15/2016] [Indexed: 11/20/2022] Open
Abstract
Cysteine is a commercially important amino acid; however, it lacks an efficient fermentative production method. Due to its cytotoxicity, intracellular cysteine levels are stringently controlled via several regulatory modes. Managing its toxic effects as well as understanding and deregulating the complexities of regulation are crucial for establishing the fermentative production of cysteine. The regulatory modes include feedback inhibition of key metabolic enzymes, degradation, efflux pumps, and the transcriptional regulation of biosynthetic genes by a master cysteine regulator, CysB. These processes have been extensively studied using Escherichia coli for overproducing cysteine by fermentation. In this study, we genetically engineered Pantoea ananatis, an emerging host for the fermentative production of bio-based materials, to identify key factors required for cysteine production. According to this and our previous studies, we identified a major cysteine desulfhydrase gene, ccdA (formerly PAJ_0331), involved in cysteine degradation, and the cysteine efflux pump genes cefA and cefB (formerly PAJ_3026 and PAJ_p0018, respectively), which may be responsible for downregulating the intracellular cysteine level. Our findings revealed that ccdA deletion and cefA and cefB overexpression are crucial factors for establishing fermentative cysteine production in P. ananatis and for obtaining a higher cysteine yield when combined with genes in the cysteine biosynthetic pathway. To our knowledge, this is the first demonstration of cysteine production in P. ananatis, which has fundamental implications for establishing overproduction in this microbe.IMPORTANCE The efficient production of cysteine is a major challenge in the amino acid fermentation industry. In this study, we identified cysteine efflux pumps and degradation pathways as essential elements and genetically engineered Pantoea ananatis, an emerging host for the fermentative production of bio-based materials, to establish the fermentative production of cysteine. This study provides crucial insights into the design and construction of cysteine-producing strains, which may play central roles in realizing commercial basis production.
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l-Cysteine Metabolism and Fermentation in Microorganisms. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2016; 159:129-151. [DOI: 10.1007/10_2016_29] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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28
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Efflux systems in bacteria and their metabolic engineering applications. Appl Microbiol Biotechnol 2015; 99:9381-93. [PMID: 26363557 DOI: 10.1007/s00253-015-6963-9] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Revised: 08/20/2015] [Accepted: 08/22/2015] [Indexed: 10/23/2022]
Abstract
The production of valuable chemicals from metabolically engineered microbes can be limited by excretion from the cell. Efflux is often overlooked as a bottleneck in metabolic pathways, despite its impact on alleviating feedback inhibition and product toxicity. In the past, it has been assumed that endogenous efflux pumps and membrane porins can accommodate product efflux rates; however, there are an increasing number of examples wherein overexpressing efflux systems is required to improve metabolite production. In this review, we highlight specific examples from the literature where metabolite export has been studied to identify unknown transporters, increase tolerance to metabolites, and improve the production capabilities of engineered bacteria. The review focuses on the export of a broad spectrum of valuable chemicals including amino acids, sugars, flavins, biofuels, and solvents. The combined set of examples supports the hypothesis that efflux systems can be identified and engineered to confer export capabilities on industrially relevant microbes.
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Karau A, Grayson I. Amino acids in human and animal nutrition. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2014; 143:189-228. [PMID: 24676880 DOI: 10.1007/10_2014_269] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Amino acids are key components of human and animal nutrition, both as part of a protein-containing diet, and as supplemented individual products. In the last 10 years there has been a marked move away from the extraction of amino acids from natural products, which has been replaced by efficient fermentation processes using nonanimal carbon sources. Today several amino acids are produced in fermentation plants with capacities of more than 100,000 tonnes to serve the requirements of animal feed and human nutrition. The main fermentative amino acids for animal nutrition are L-lysine, L-threonine, and L-tryptophan. DL-Methionine continues to be manufactured for animal feed use principally by chemical synthesis, and a pharmaceutical grade is manufactured by enzymatic resolution. Amino acids play an important role in medical nutrition, particularly in parenteral nutrition, where there are high purity requirements for infusion grade products. Amino acids are also appearing more often in dietary supplements, initially for performance athletes, but increasingly for the general population. As the understanding of the effects of the individual amino acids on the human metabolism is deepened, more specialized product mixtures are being offered to improve athletic performance and for body-building.
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Affiliation(s)
- Andreas Karau
- Evonik Industries AG, Business Line Health Care, Rodenbacher Chaussee 4, 63457, Hanau-Wolfgang, Germany,
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Xu H, Cai S, Xu L, Yang Y. Water-stable three-dimensional ultrafine fibrous scaffolds from keratin for cartilage tissue engineering. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:8461-70. [PMID: 25010870 DOI: 10.1021/la500768b] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Intrinsically water-stable scaffolds composed of ultrafine keratin fibers oriented randomly and evenly in three dimensions were electrospun for cartilage tissue engineering. Keratin has been recognized as a biomaterial that could substantially support the growth and development of multiple cell lines. Besides, three-dimensional (3D) ultrafine fibrous structures were preferred in tissue engineering due to their structural similarity to native extracellular matrices in soft tissues. Recently, we have developed a nontraditional approach to developing 3D fibrous scaffolds from alcohol-soluble corn protein, zein, and verified their structural advantages in tissue engineering. However, keratin with highly cross-linked molecular structures could not be readily dissolved in common solvents for fiber spinning, which required the remarkable drawability of solution. So far, 3D fibrous scaffolds from pure keratin for biomedical applications have not been reported. In this research, the highly cross-linked keratin from chicken feathers was de-cross-linked and disentangled into linear and aligned molecules with preserved molecular weights, forming highly stretchable spinning dope. The solution was readily electrospun into scaffolds with ultrafine keratin fibers oriented randomly in three dimensions. Due to the highly cross-linked molecular structures, keratin scaffolds showed intrinsic water stability. Adipose-derived mesenchymal stem cells could penetrate much deeper, proliferate, and chondrogenically differentiate remarkably better on the 3D keratin scaffolds than on 2D PLA fibrous scaffolds, 3D soy protein fibrous scaffolds, or 3D commercial nonfibrous scaffolds. In summary, the electrospun 3D ultrafine fibrous scaffolds from keratin could be promising candidates for cartilage tissue engineering.
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Affiliation(s)
- Helan Xu
- Department of Textiles, Merchandising and Fashion Design, 234, HECO Building, University of Nebraska-Lincoln , Lincoln, Nebraska 68583-0802, United States
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Corynebacterium glutamicum sdhA encoding succinate dehydrogenase subunit A plays a role in cysR-mediated sulfur metabolism. Appl Microbiol Biotechnol 2014; 98:6751-9. [DOI: 10.1007/s00253-014-5823-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Revised: 05/08/2014] [Accepted: 05/10/2014] [Indexed: 10/25/2022]
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Youn SH, Park HW, Choe D, Shin CS. Preparation of eutectic substrate mixtures for enzymatic conversion of ATC to l-cysteine at high concentration levels. Bioprocess Biosyst Eng 2013; 37:1193-200. [DOI: 10.1007/s00449-013-1090-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Accepted: 11/03/2013] [Indexed: 11/30/2022]
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The Biotechnological Potential of Corynebacterium glutamicum, from Umami to Chemurgy. CORYNEBACTERIUM GLUTAMICUM 2013. [DOI: 10.1007/978-3-642-29857-8_1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Ikeda M, Takeno S. Amino Acid Production by Corynebacterium glutamicum. CORYNEBACTERIUM GLUTAMICUM 2013. [DOI: 10.1007/978-3-642-29857-8_4] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Fan C, Li Z, Ye Q. Two-Stage Cultivation of Pseudomonas sp. F12 for the Production of Enzymes Converting dl-2-Amino-Δ2-thiazoline-4-carboxylic Acid to l-Cysteine. Appl Biochem Biotechnol 2012; 168:1867-79. [DOI: 10.1007/s12010-012-9903-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2012] [Accepted: 09/18/2012] [Indexed: 11/29/2022]
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Youn SH, Park HW, Shin CS. Enhanced dissolution of the substrate d,l-2-amino-Δ2-thiazoline-4-carboxylic acid and enzymatic production of l-cysteine at high concentrations. Eng Life Sci 2012. [DOI: 10.1002/elsc.201200002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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NISHIUCHI H, KOHMURA M, WAKABAYASHI H. A Rapid and Precise Method to Determine Cysteine Content in Food Materials using 4-(aminosulfonyl)-7-fluoro-2,1,3-benzoxadiazole. FOOD SCIENCE AND TECHNOLOGY RESEARCH 2011. [DOI: 10.3136/fstr.17.341] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Rodríguez-Zavala JS, Ortiz-Cruz MA, Mendoza-Hernández G, Moreno-Sánchez R. Increased synthesis of α-tocopherol, paramylon and tyrosine by Euglena gracilis under conditions of high biomass production. J Appl Microbiol 2010; 109:2160-72. [PMID: 20854454 DOI: 10.1111/j.1365-2672.2010.04848.x] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AIMS To analyse the production of different metabolites by dark-grown Euglena gracilis under conditions found to render high cell growth. METHODS AND RESULTS The combination of glutamate (5 g l(-1) ), malate (2 g l(-1) ) and ethanol (10 ml l(-1) ) (GM + EtOH); glutamate (7·15 g l(-1) ) and ethanol (10 ml l(-1) ); or malate (8·16 g l(-1) ), glucose (10·6 g l(-1) ) and NH(4) Cl (1·8 g l(-1) ) as carbon and nitrogen sources, promoted an increase of 5·6, 3·7 and 2·6-fold, respectively, in biomass concentration in comparison with glutamate and malate (GM). In turn, the production of α-tocopherol after 120 h identified by LC-MS was 3·7 ± 0·2, 2·4 ± 0·1 and 2 ± 0·1 mg [g dry weight (DW)](-1) , respectively, while in the control medium (GM) it was 0·72 ± 0·1 mg (g DW)(-1) . For paramylon synthesis, the addition of EtOH or glucose induced a higher production. Amino acids were assayed by RP-HPLC; Tyr a tocopherol precursor and Ala an amino acid with antioxidant activity were the amino acids synthesized at higher concentration. CONCLUSIONS Dark-grown E. gracilis Z is a suitable source for the generation of the biotechnologically relevant metabolites tyrosine, α-tocopherol and paramylon. SIGNIFICANCE AND IMPACT OF THE STUDY By combining different carbon and nitrogen sources and inducing a tolerable stress to the cell by adding ethanol, it was possible to increase the production of biomass, paramylon, α-tocopherol and some amino acids. The concentrations of α-tocopherol achieved in this study are higher than others reported previously for Euglena, plant and algal systems. This work helps to understand the effect of different carbon sources on the synthesis of bio-molecules by E. gracilis and can be used as a basis for future works to improve the production of different metabolites of biotechnological importance by this organism.
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Affiliation(s)
- J S Rodríguez-Zavala
- Departamento de Bioquímica, Instituto Nacional de Cardiología, México D.F., México.
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Sanchez S, Demain AL. Metabolic regulation and overproduction of primary metabolites. Microb Biotechnol 2008; 1:283-319. [PMID: 21261849 PMCID: PMC3815394 DOI: 10.1111/j.1751-7915.2007.00015.x] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2007] [Revised: 10/04/2007] [Accepted: 10/23/2007] [Indexed: 12/01/2022] Open
Abstract
Overproduction of microbial metabolites is related to developmental phases of microorganisms. Inducers, effectors, inhibitors and various signal molecules play a role in different types of overproduction. Biosynthesis of enzymes catalysing metabolic reactions in microbial cells is controlled by well-known positive and negative mechanisms, e.g. induction, nutritional regulation (carbon or nitrogen source regulation), feedback regulation, etc. The microbial production of primary metabolites contributes significantly to the quality of life. Fermentative production of these compounds is still an important goal of modern biotechnology. Through fermentation, microorganisms growing on inexpensive carbon and nitrogen sources produce valuable products such as amino acids, nucleotides, organic acids and vitamins which can be added to food to enhance its flavour, or increase its nutritive values. The contribution of microorganisms goes well beyond the food and health industries with the renewed interest in solvent fermentations. Microorganisms have the potential to provide many petroleum-derived products as well as the ethanol necessary for liquid fuel. Additional applications of primary metabolites lie in their impact as precursors of many pharmaceutical compounds. The roles of primary metabolites and the microbes which produce them will certainly increase in importance as time goes on. In the early years of fermentation processes, development of producing strains initially depended on classical strain breeding involving repeated random mutations, each followed by screening or selection. More recently, methods of molecular genetics have been used for the overproduction of primary metabolic products. The development of modern tools of molecular biology enabled more rational approaches for strain improvement. Techniques of transcriptome, proteome and metabolome analysis, as well as metabolic flux analysis. have recently been introduced in order to identify new and important target genes and to quantify metabolic activities necessary for further strain improvement.
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Affiliation(s)
- Sergio Sanchez
- Departamento de Biologia Molecular y Biotecnologia, Instituto de Investigaciones Biomedicas, Universidad Nacional Autonoma de Mexico (UNAM), Mexico City, Mexico
| | - Arnold L. Demain
- Research Institute for Scientists Emeriti (RISE), Drew University, Madison, NJ 07940, USA
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Liang GB, Du GC, Chen J. A novel strategy of enhanced glutathione production in high cell density cultivation of Candida utilis—Cysteine addition combined with dissolved oxygen controlling. Enzyme Microb Technol 2008. [DOI: 10.1016/j.enzmictec.2007.10.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Van Dyk TK. Bacterial Efflux Transport in Biotechnology. ADVANCES IN APPLIED MICROBIOLOGY 2008; 63:231-47. [DOI: 10.1016/s0065-2164(07)00006-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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