Accumulation of γ-aminobutyric acid by Enterococcus avium 9184 in scallop solution in a two-stage fermentation strategy.

Haoyue Yang,Song Liu,Linfeng Hu,Pengcheng Li,Ronge Xing

doi:10.1111/1751-7915.12301

Abstract

SummaryIn this study, a new bacterial strain having a high ability to produce γ‐aminobutyric acid (GABA) was isolated from naturally fermented scallop solution and was identified as E nterococcus avium. To the best of our knowledge, this is the first study to prove that E . avium possesses glutamate decarboxylase activity. The strain was then mutagenized with UV radiation and was designated as E . avium 9184. Scallop solution was used as the culture medium to produce GABA. A two‐stage fermentation strategy was applied to accumulate GABA. In the first stage, cell growth was regulated. Optimum conditions for cell growth were pH, 6.5; temperature, 37°C; and glucose concentration, 10 g·L−1. This produced a maximum dry cell mass of 2.10 g·L−1. In the second stage, GABA formation was regulated. GABA concentration reached 3.71 g·L−1 at 96 h pH 6.0, 37°C and initial l‐monosodium glutamate concentration of 10 g·L−1. Thus, compared with traditional one‐stage fermentation, the two‐stage fermentation significantly increased GABA accumulation. These results provide preliminary data to produce GABA using E . avium and also provide a new approach to process and utilize shellfish.

Highlights

Introduction γAminobutyric acid (GABA) has various biological properties such as anti-anxiety, anti-hypertension, and growth-promoting effects (Siragusa et al, 2007)
Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology, Microbial Biotechnology, 9, 478–485
In this study, the fermentation temperature was maintained at 37°C, which guaranteed good growth of E. avium 9184 and good activity of glutamate decarboxylase (GAD)

Summary

Introduction

Introduction γAminobutyric acid (GABA) has various biological properties such as anti-anxiety, anti-hypertension, and growth-promoting effects (Siragusa et al, 2007). The development and application of GABA have gained popularity in recent times. Chemical transformation and biotransformation were commonly used for producing GABA (Ger offen, 1970; Plokhov et al, 2000; Li and Cao, 2007). Chemical transformation, which is more common in patent documentations, provides high yield and high purity of GABA, it requires toxic solvents that produce toxic residues. This limits its application in the food industry. Biotransformation, on the other hand, associates with benefits such as safe application in the food industry, environmental protection and energy saving (Komatsuzaki et al, 2005b)

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