title: Contribution of the activated catalase to oxidative stress resistance and γ-aminobutyric acid production in Lactobacillus brevis.
abstract: Lactic acid bacteria (LAB) are generally sensitive to H2O2, a compound which can paradoxically produce themselves and lead to the growth arrest and cell death. To counteract the potentially toxic effects of this compound, the gene katE encoding a heme-dependent catalase (CAT) belonging to the family of monofunctional CATs was cloned from Lactobacillus brevis CGMCC1306. The enhanced homologous CAT expression was achieved using the NICE system. L. brevis cells with overexpressed CAT showed 685-fold and 823-fold higher survival when exposed to 30mmol/L of H2O2and long-term aerated stress (after 72h), respectively, than that of the wild type cells. Furtherly, the effects of activated CAT on GABA production in L. brevis were investigated. A GABA production level of 66.4g/L was achieved using two-step biotransformation that successively employed the growing and resting cells derived from engineering L. brevis CAT. These results demonstrated clearly that overexpression of the KatE gene in L. brevis led to a marked increased survival in oxidizing environment, and shed light on a novel feasible approach to enhance the GABA production level by improving the antioxidative properties.
authors.affiliation: 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.
authors.forename: Changjiang
authors.initials: C
authors.lastname: Lyu
authors.affiliation: School of Biotechnology and Chemical Engineering, Ningbo Institute of Technology, Zhejiang University, Ningbo 315100, China.
authors.forename: Sheng
authors.initials: S
authors.lastname: Hu
authors.affiliation: School of Biological and Chemical Engineering, Zhejiang University of Science and Technology, Hangzhou 310023, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Huang
authors.affiliation: College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China.
authors.forename: Maiqi
authors.initials: M
authors.lastname: Luo
authors.affiliation: College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Lu
authors.affiliation: 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. Electronic address: meilh@zju.edu.cn.
authors.forename: Lehe
authors.initials: L
authors.lastname: Mei
authors.affiliation: College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China. Electronic address: yaosj@zju.edu.cn.
authors.forename: Shanjing
authors.initials: S
authors.lastname: Yao
mesh_terms: D000975:Antioxidants / Q000378:metabolism*; D002374:Catalase / Q000235:genetics* / Q000378:metabolism*; D003001:Cloning, Molecular; D006861:Hydrogen Peroxide / Q000378:metabolism; D052196:Levilactobacillus brevis / Q000201:enzymology* / Q000378:metabolism*; D010084:Oxidation-Reduction; D018384:Oxidative Stress / Q000502:physiology; D005680:gamma-Aminobutyric Acid / Q000096:biosynthesis*
chemical_list: D000975:Antioxidants; D005680:gamma-Aminobutyric Acid; D006861:Hydrogen Peroxide; C102664:hydroperoxidase II; D002374:Catalase
keywords: Catalase; GABA; Lactobacillus brevis; Overexpression; Oxidative stress