College of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, People's Republic of China.
Prep Biochem Biotechnol. 2020;50(10):1023-1030. doi: 10.1080/10826068.2020.1780610. Epub 2020 Jun 18.
Poly-γ-glutamate (γ-PGA) is a natural macromolecule peptide, and is widely used in the food, medicine, and pharmaceutical industries. In this study, heat- and osmotic shock were used to improve the production of γ-PGA in ZJS18, and its molecular mechanism was explored. The results indicated that the heat- and osmotic shock significantly promoted the production of γ-PGA owing to the stress response of cells to adverse environment. The highest concentrations of γ-PGA reached 14.53 and 15.98 g/l under heat- and osmotic shock, respectively. The activities of five enzymes related to the metabolism of the endogenous glutamate were determined and analyzed. It was found that the activities of glucose-6-phosphate dehydrogenase, isocitrate dehydrogenase, glutamate dehydrogenase and glutamate synthase were significantly altered during heat- and osmotic shock, while the activity of α-ketoglutarate dehydrogenase only showed a little alteration. This study provides a basis for the industrial production and use of γ-PGA, and for understanding its biosynthetic mechanism in ZJS18.
聚-γ-谷氨酸（γ-PGA）是一种天然高分子肽，广泛应用于食品、医药和制药行业。本研究采用热激和渗透压休克来提高 ZJS18 中 γ-PGA 的产量，并探讨了其分子机制。结果表明，由于细胞对不良环境的应激反应，热激和渗透压休克显著促进了 γ-PGA 的生产。在热激和渗透压休克下，γ-PGA 的最高浓度分别达到 14.53 和 15.98g/L。测定并分析了与内源性谷氨酸代谢相关的五种酶的活性。结果发现，在热激和渗透压休克过程中，葡萄糖-6-磷酸脱氢酶、异柠檬酸脱氢酶、谷氨酸脱氢酶和谷氨酸合酶的活性发生了显著变化，而α-酮戊二酸脱氢酶的活性仅略有变化。本研究为 γ-PGA 的工业生产和应用提供了依据，也为了解 ZJS18 中 γ-PGA 的生物合成机制提供了依据。
