Biosynthesis of γ-aminobutyrate by engineered Lactobacillus brevis cells immobilized in gellan gum gel beads

Chang-Jiang Lyu; Lu Liu; Jun Huang; Wei-Rui Zhao; Sheng Hu; Le-He Mei; Shan-Jing Yao

doi:10.1016/j.jbiosc.2019.01.010

Biosynthesis of γ-aminobutyrate by engineered Lactobacillus brevis cells immobilized in gellan gum gel beads

J Biosci Bioeng. 2019 Aug;128(2):123-128. doi: 10.1016/j.jbiosc.2019.01.010. Epub 2019 Feb 7.

Authors

Chang-Jiang Lyu¹, Lu Liu², Jun Huang³, Wei-Rui Zhao⁴, Sheng Hu⁴, Le-He Mei⁵, Shan-Jing Yao⁶

Affiliations

¹ School of Biological and Chemical Engineering, Zhejiang University of Science and Technology, Hangzhou 310023, China; College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China.
² College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China.
³ School of Biological and Chemical Engineering, Zhejiang University of Science and Technology, Hangzhou 310023, China.
⁴ School of Biotechnology and Chemical Engineering, Ningbo Institute of Technology, Zhejiang University, Ningbo 315100, China.
⁵ College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China; School of Biotechnology and Chemical Engineering, Ningbo Institute of Technology, Zhejiang University, Ningbo 315100, China.
⁶ College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China. Electronic address: yaosj@zju.edu.cn.

PMID: 30738730
DOI: 10.1016/j.jbiosc.2019.01.010

Abstract

γ-Aminobutyrate (GABA) is an important chemical in pharmaceutical field. The use of lactic acid bacteria as biocatalysts for the conversion of l-monosodium glutamate (MSG) into GABA opens interesting perspectives for the production of this functional compound. In this work, an engineered GABA high-producing strain Lactobacillus brevis GadA_ΔC14 was constructed by overexpressing a C-terminally truncated GadA mutant, which is active in expanded pH range. After comparison with agar and κ-carrageenan, gellan gum was selected as the optimal immobilization support, and the properties of L. brevis GadA_ΔC14 cells encapsulated in this hydrogel were examined. The optimum pH and temperature of immobilized cells were found to be 40°C and pH 4.4, respectively. It was also observed that operational and thermal stabilities of the cells were increased with immobilization. After ten consecutive reaction cycles, the total amounts of GABA produced by the immobilized cells summed up to 87.56 g/L under the optimum experimental conditions. Taken together, the improved stability and good usability make the immobilized L. brevis GadA_ΔC14 cells more valuable for industrial applications.

Keywords: GABA; Gellan gum; Glutamate decarboxylase; Immobilization; Lactobacillus brevis.

MeSH terms

Cells, Immobilized / metabolism*
Fermentation
Genetic Engineering*
Hydrogen-Ion Concentration
Levilactobacillus brevis / cytology*
Levilactobacillus brevis / genetics*
Levilactobacillus brevis / metabolism
Microspheres*
Polysaccharides, Bacterial / chemistry*
Temperature
gamma-Aminobutyric Acid / biosynthesis*

Substances

Polysaccharides, Bacterial
gamma-Aminobutyric Acid
gellan gum