Enhancing effect of macroporous adsorption resin on gamma-aminobutyric acid production by Enterococcus faecium in whole-cell biotransformation system

Yang, Shou-Yun; Liu, Shumin; Jiang, Min; Wang, Biao-Shi; Peng, Luo-Hui; Zeng, Chan

doi:10.1007/s00726-020-02850-3

Cited by 5 publications

(4 citation statements)

References 39 publications

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“…In addition to the screening of GAD to enhance the efficiency of GABA biosynthesis in both enzymatic methods and microbial production, applying l -Glu as a substrate instead of monosodium glutamate (MSG) solution or cation-exchange resins/macroporous adsorption resin to maintain the acidic pH was also an effective solution. − Many attempts were also carried out by the coexpression of GAD with GadC, which is responsible for the extracellular transport of l -glutamate and the intracellular excretion of GABA, using the synthetic protein scaffold or assembling a single protein–protein interaction domain. − In addition, supplementation with the cofactor PLP has been reported to be beneficial for GABA production; examples include the addition of PLP to the fermentation medium, for which the cost of PLP is high, or the expression of the plk gene (encoding pyridoxal kinase), which catalyzes the ATP-dependent phosphorylation reaction of pyridoxal to produce PLP …”

Section: Introductionmentioning

confidence: 99%

Integrating Enzyme Evolution and Metabolic Engineering to Improve the Productivity of Γ-Aminobutyric Acid by Whole-Cell Biosynthesis in Escherichia Coli

Yang

Huo

Yiping

et al. 2023

J. Agric. Food Chem.

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γ-Aminobutyric acid (GABA) is used widely in various fields, such as agriculture, food, pharmaceuticals, and biobased chemicals. Based on glutamate decarboxylase (GadBM4) derived from our previous work, three mutants, GadM4-2, GadM4-8, and GadM4-31, were obtained by integrating enzyme evolution and high-throughput screening methods. The GABA productivity obtained through whole-cell bioconversion using recombinant Escherichia coli cells harboring mutant GadBM4-2 was enhanced by 20.27% compared to that of the original GadBM4. Further introduction of the central regulator GadE of the acid resistance system and the enzymes from the deoxyxylulose-5-phosphate-independent pyridoxal 5′-phosphate biosynthesis pathway resulted in a 24.92% improvement in GABA productivity, reaching 76.70 g/L/h without any cofactor addition with a greater than 99% conversion ratio. Finally, when one-step bioconversion was applied for the whole-cell catalysis in a 5 L bioreactor, the titer of GABA reached 307.5 ± 5.94 g/L with a productivity of 61.49 g/L/h by using crude l-glutamic acid (l-Glu) as the substrate. Thus, the biocatalyst constructed above combined with the whole-cell bioconversion method represents an effective approach for industrial GABA production.

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Section: Introductionmentioning

confidence: 99%

Integrating Enzyme Evolution and Metabolic Engineering to Improve the Productivity of Γ-Aminobutyric Acid by Whole-Cell Biosynthesis in Escherichia Coli

Yang

Huo

Yiping

et al. 2023

J. Agric. Food Chem.

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“…In this experiment, butyric acid was only detected in the VG treatment group, possibly due to fermentation by Enterococcus . Previous research has demonstrated that Enterococcus can produce butyric acid through the catalysis of glutamate [ 69 , 70 ].…”

Section: Discussionmentioning

confidence: 99%

Influences of Growth Stage and Ensiling Time on Fermentation Characteristics, Nitrite, and Bacterial Communities during Ensiling of Alfalfa

An,

Sun,

Liu

et al. 2023

Plants

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This study examined the impacts of growth stage and ensiling duration on the fermentation characteristics, nitrite content, and bacterial communities during the ensiling of alfalfa. Harvested alfalfa was divided into two groups: vegetative growth stage (VG) and late budding stage (LB). The fresh alfalfa underwent wilting until reaching approximately 65% moisture content, followed by natural fermentation. The experiment followed a completely randomized design, with samples collected after the wilting of alfalfa raw materials (MR) and on days 1, 3, 5, 7, 15, 30, and 60 of fermentation. The growth stage significantly influenced the chemical composition of alfalfa, with crude protein content being significantly higher in the vegetative growth stage alfalfa compared to that in the late budding stage (p < 0.05). Soluble carbohydrates, neutral detergent fiber, and acid detergent fiber content were significantly lower in the vegetative growth stage compared to the late budding stage (p < 0.05). Nitrite content, nitrate content, nitrite reductase activity, and nitrate reductase activity were all significantly higher in the vegetative growth stage compared to the late budding stage (p < 0.05). In terms of fermentation parameters, silage from the late budding stage exhibited superior characteristics compared to that from the vegetative growth stage. Compared to the alfalfa silage during the vegetative growth stage, the late budding stage group exhibited a higher lactate content and lower pH level. Notably, butyric acid was only detected in the silage from the vegetative growth stage group. Throughout the ensiling process, nitrite content, nitrate levels, nitrite reductase activity, and nitrate reductase activity decreased in both treatment groups. The dominant lactic acid bacteria differed between the two groups, with Enterococcus being predominant in vegetative growth stage alfalfa silage, and Weissella being predominant in late budding stage silage, transitioning to Lactiplantibacillus in the later stages of fermentation. On the 3rd day of silage fermentation, the vegetative growth stage group exhibited the highest abundance of Enterococcus, which subsequently decreased to its lowest level on the 15th day. Correlation analysis revealed that lactic acid bacteria, including Limosilactobacillus, Levilactobacillus, Loigolactobacillus, Pediococcus, Lactiplantibacillus, and Weissella, played a key role in nitrite and nitrate degradation in alfalfa silage. The presence of nitrite may be linked to Erwinia, unclassified_o__Enterobacterales, Pantoea, Exiguobacterium, Enterobacter, and Allorhizobium–Neorhizobium–Pararhizobium–Rhizobium.

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“…This finding indicated the presence of a mass transfer barrier within the whole cell, where the pH of the extracellular environment reached 4.4 to ensure the intracellular pH reached 5.0. 86 Since GABA is decomposed into SSA through GABA-T, the pH conditions that promote optimal GABA-T activity also need to be considered in GABA synthesis. For example, GABA-T isolated from Pseudomonas aeruginosa exhibited the highest enzymatic activity toward GABA at pH 8.5.…”

Section: Factorsmentioning

confidence: 99%

“…Yang et al found that the optimal pH for the reaction activity of pure GAD and whole-cell GAD from Enterococcus faecalis was 5.0 and 4.4, respectively, and the pH range of the reaction system involving pure GAD was significantly higher than that of whole-cells GAD. This finding indicated the presence of a mass transfer barrier within the whole cell, where the pH of the extracellular environment reached 4.4 to ensure the intracellular pH reached 5.0 . Since GABA is decomposed into SSA through GABA-T, the pH conditions that promote optimal GABA-T activity also need to be considered in GABA synthesis.…”

Section: Isolation and Purification Of Gaba From Microorganismsmentioning

confidence: 99%

Microbial-Derived γ-Aminobutyric Acid: Synthesis, Purification, Physiological Function, and Applications

Han,

Zhao,

Zhao

et al. 2023

J. Agric. Food Chem.

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γ-Aminobutyric acid (GABA) is an important nonprotein amino acid that extensively exists in nature. At present, GABA is mainly obtained through chemical synthesis, plant enrichment, and microbial production, among which microbial production has received widespread attention due to its safety and environmental benefits. After using microbial fermentation to obtain GABA, it is necessary to be isolated and purified to ensure its quality and suitability for various industries such as food, agriculture, livestock, pharmaceutics, and others. This article provides a comprehensive review of the different sources of GABA, including its presence in nature and the synthesis methods. The factors affecting the production of microbial-derived GABA and its isolation and purification methods are further elucidated. Moreover, the main physiological functions of GABA and its application in different fields are also reviewed. By advancing our understanding of GABA, we can unlock its full potential and further utilize it in various fields to improve human health and well-being.

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Enhancing effect of macroporous adsorption resin on gamma-aminobutyric acid production by Enterococcus faecium in whole-cell biotransformation system

Cited by 5 publications

References 39 publications

Integrating Enzyme Evolution and Metabolic Engineering to Improve the Productivity of Γ-Aminobutyric Acid by Whole-Cell Biosynthesis in Escherichia Coli

Integrating Enzyme Evolution and Metabolic Engineering to Improve the Productivity of Γ-Aminobutyric Acid by Whole-Cell Biosynthesis in Escherichia Coli

Influences of Growth Stage and Ensiling Time on Fermentation Characteristics, Nitrite, and Bacterial Communities during Ensiling of Alfalfa

Microbial-Derived γ-Aminobutyric Acid: Synthesis, Purification, Physiological Function, and Applications

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