Whole-cell conversion of l-glutamic acid into gamma-aminobutyric acid by metabolically engineered Escherichia coli

Ke, Chongrong; Yang, Xinwei; Rao, Huanxin; Zeng, Wenchao; Hu, Meirong; Tao, Yong; Huang, Jianzhong

doi:10.1186/s40064-016-2217-2

Cited by 36 publications

(31 citation statements)

References 31 publications

(48 reference statements)

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“…The use of enzymes in organic synthesis (biocatalysis) may have some potential advantages compared to other catalytic alternatives, as enzymes display often a high specificity– reducing the possibility of generation of by‐products–, and perform well under mild reaction conditions, which can lead to energy savings and to more sustainable processes . Moreover, outstanding advances in protein engineering techniques and enzymatic immobilization have resulted in more active, robust, and stable biocatalysts with commercial application potential . As a result, a number of biocatalytic reactions have been successfully implemented already at industrial scale…”

Section: Motivation Synergies Among Biocatalysis Environmentally‐frmentioning

confidence: 99%

Continuous Biocatalysis in Environmentally‐Friendly Media: A Triple Synergy for Future Sustainable Processes

Guajardo

Marı́a²

2019

ChemCatChem

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Enzyme catalysis (biocatalysis) is a mature strategy to perform organic synthesis with high selectivity and under mild reaction conditions. However, despite their origin and biodegradability, the simple use of enzymes is not sufficient to validate a process as green or sustainable. To reinforce the value that biocatalysis may offer, enzymatic processes can be established in environmentally‐friendly media, such as water, neoteric solvents (e. g. deep‐eutectic‐solvents, DES), biogenic solvents (e. g. 2‐MeTHF or terpenes), or even solvent‐free systems (if substrates allow that). Furthermore, these options can be conducted in continuous biocatalytic processes, which are more efficient and sustainable. Hence, a triple synergy is generated, and very promising environmentally‐friendly options can be envisaged. This conceptual paper discusses these alternatives, providing relevant, recently reported, successful examples.

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Section: Motivation Synergies Among Biocatalysis Environmentally‐frmentioning

confidence: 99%

Continuous Biocatalysis in Environmentally‐Friendly Media: A Triple Synergy for Future Sustainable Processes

Guajardo

Marı́a²

2019

ChemCatChem

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“…Production titers up to 125 g/L of cadaverine in sugar-based fed-batch fermentations have been reported for recombinant C. glutamicum strains (Kim et al, 2020). The highest reported production titer of GABA was achieved with recombinant E. coli strains producing up to 308.96 g/l of this compound on sugar-based media and with the GABA precursor L-glutamate added in excess (Ke et al, 2016;Xu et al, 2017). Lactobacillus brevis strains have been constructed and reported to display GABA production titers up to 201 g/L for resting cells (Shi et al, 2017).…”

Section: Discussionmentioning

confidence: 99%

Production of Value-Added Chemicals by Bacillus methanolicus Strains Cultivated on Mannitol and Extracts of Seaweed Saccharina latissima at 50°C

et al. 2020

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The facultative methylotroph Bacillus methanolicus MGA3 has previously been genetically engineered to overproduce the amino acids L-lysine and L-glutamate and their derivatives cadaverine and γ-aminobutyric acid (GABA) from methanol at 50 • C. We here explored the potential of utilizing the sugar alcohol mannitol and seaweed extract (SWE) containing mannitol, as alternative feedstocks for production of chemicals by fermentation using B. methanolicus. Extracts of the brown algae Saccharina latissima harvested in the Trondheim Fjord in Norway were prepared and found to contain 12-13 g/l of mannitol, with conductivities corresponding to a salt content of ∼2% NaCl. Initially, 12 B. methanolicus wild type strains were tested for tolerance to various SWE concentrations, and some strains including MGA3 could grow on 50% SWE medium. Non-methylotrophic and methylotrophic growth of B. methanolicus rely on differences in regulation of metabolic pathways, and we compared production titers of GABA and cadaverine under such growth conditions. Shake flask experiments showed that recombinant MGA3 strains could produce similar and higher titers of cadaverine during growth on 50% SWE and mannitol, compared to on methanol. GABA production levels under these conditions were however low compared to growth on methanol. We present the first fed-batch mannitol fermentation of B. methanolicus and production of 6.3 g/l cadaverine. Finally, we constructed a recombinant MGA3 strain synthesizing the C30 terpenoids 4,4 -diaponeurosporene and 4,4 -diapolycopene, experimentally confirming that B. methanolicus has a functional methylerythritol phosphate (MEP) pathway. Together, our results contribute to extending the range of both the feedstocks for growth and products that can be synthesized by B. methanolicus.

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“…The concentrations of GABA and L-Glu were measured using the phenyl isothiocyanate derivation method by high-performance liquid chromatography (HPLC; Agilent 1260, Hewlett-Packard, Wilmington, NC, USA) equipped with an Agilent Zorbax Eclipse amino acid analysis (AAA) column (4.6 £ 150 mm, 3.5 mm). Analyses were performed at 40 C using a linear gradient of acetonitrile and 50 mmol L ¡1 sodium acetate as the mobile phases at a flow rate of 0.5 mL min ¡1 , and monitored at 254 nm [25]. The standard curves for GABA and L-Glu (Sigma, Missouri, USA) were obtained using the same procedure.…”

Section: Methodsmentioning

confidence: 99%

“…After induction by IPTG for several hours, the recombinant cells were centrifuged at 8,000 £ g for 10 min to collect cells for bioconversion. Wet cells at 25 g L ¡1 (OD 600 of 30) were resuspended in deionized water (DW) with different concentrations of L-Glu (1, 2, 3 and 4 mol L ¡1 ) at 45 C to detect the production of GABA [25]. For GABA production by the supernatant of the cell lysate, the same number of cells (OD 600 of 30) were disrupted by sonication, then centrifuged to collect the supernatant as the catalyst.…”

Section: Bioconversion Conditionsmentioning

confidence: 99%

“…Plokhov et al [24] used a recombinant E. coli strain as a wholecell biocatalyst, and 138 g GABA was achieved from 200 g L-Glu at a conversion yield of 98.5%; Yamano et al [23] used E. coli NBRC 3806 as a whole-cell biocatalyst, and 303.7 g GABA was produced from 560 g of L-Glu via repeating 14 times. Ke et al [25] applied crude L-Glu as the substrate for GABA whole-cell bioconversion, and 614.15 g L ¡1 GABA with a molar yield over 99% was achieved by recombinant E. coli reused for three cycles. In addition, Lactobacillus brevis TCCC 13 007 cells could also be used as the whole-cell catalyst, resulting in 201.18 g L ¡1 GABA with 99.4mol% by 10 h bioconversion [26].…”

Section: Introductionmentioning

confidence: 99%

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Efficient gamma-aminobutyric acid bioconversion by engineered Escherichia coli

Wei

Ren

et al. 2018

Biotechnology & Biotechnological Equipment

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Gamma-aminobutyric acid (GABA) can be converted into 2-pyrrolidone, an intermediate in the synthesis of nylon 4 and agrochemicals, which has great potential for application in the chemical industry. The main aim of this work was to construct a simple and efficient process for industrial production of GABA from L-glutamic acid (L-Glu) by whole-cell bioconversion. The gene encoding glutamate decarboxylase (GAD) from Lactococcus lactis FJNUGA01 was overexpressed using the most available vector in Escherichia coli, pET-28a. GABA production was enhanced by optimizing the concentration of the catalyst isopropyl-b-D-thiogalactoside (IPTG), induction temperature and induction time. After optimization, GABA production reached 98.4 g L ¡1 with 96 mol% conversion within 6 h was achieved by whole-cell conversion using the cells induced with 1 mmol L ¡1 IPTG for 12 h at 30 C. Furthermore, when the initial concentration of L-Glu was adjusted, 204.12 g L ¡1 GABA with 34 g L ¡1 h ¡1 productivity was reached using 2 mol L ¡1 L-Glu as the substrate. During the 6 h whole-cell bioconversion process, almost all L-Glu was converted to GABA with a conversion efficiency of »99%. The high conversion efficiency and high productivity made the GABA purification occur downstream, and the whole process is more simple and economical for industrial application.

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Whole-cell conversion of l-glutamic acid into gamma-aminobutyric acid by metabolically engineered Escherichia coli

Cited by 36 publications

References 31 publications

Continuous Biocatalysis in Environmentally‐Friendly Media: A Triple Synergy for Future Sustainable Processes

Continuous Biocatalysis in Environmentally‐Friendly Media: A Triple Synergy for Future Sustainable Processes

Production of Value-Added Chemicals by Bacillus methanolicus Strains Cultivated on Mannitol and Extracts of Seaweed Saccharina latissima at 50°C

Efficient gamma-aminobutyric acid bioconversion by engineered Escherichia coli

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