1. Contribution of the activated catalase to oxidative stress resistance and γ-aminobutyric acid production in Lactobacillus brevis
- Author
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Maiqi Luo, Shan-Jing Yao, Lehe Mei, Changjiang Lyu, Tao Lu, Jun Huang, and Sheng Hu
- Subjects
0301 basic medicine ,030106 microbiology ,Levilactobacillus brevis ,medicine.disease_cause ,Microbiology ,Aminobutyric acid ,Antioxidants ,03 medical and health sciences ,chemistry.chemical_compound ,Biotransformation ,medicine ,Cloning, Molecular ,gamma-Aminobutyric Acid ,biology ,Lactobacillus brevis ,Wild type ,General Medicine ,Hydrogen Peroxide ,biology.organism_classification ,Catalase ,Lactic acid ,Oxidative Stress ,Biochemistry ,chemistry ,biology.protein ,Oxidation-Reduction ,Oxidative stress ,Bacteria ,Food Science - 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 H2O2 and 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.
- Published
- 2016