State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing 211816, China; College of Food Science and Light Industry, Nanjing Tech University, Nanjing 211816, China.
State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing 211816, China; College of Food Science and Light Industry, Nanjing Tech University, Nanjing 211816, China.
Bioresour Technol. 2017 Sep;239:197-203. doi: 10.1016/j.biortech.2017.05.005. Epub 2017 May 4.
This study aimed to develop non-food fermentation for the cost-effective production of poly-(γ-glutamic acid) (γ-PGA) using a novel strain of Bacillus amyloliquefaciens NX-2S. The new isolate assimilated inulin more efficiently than other carbohydrates from Jerusalem artichoke, without hydrolytic treatment. To investigate the effect of inulin on γ-PGA production, the transcript levels of γ-PGA synthetase genes (pgsB, pgsC, pgsA), regulatory genes (comA, degQ, degS), and the glutamic acid biosynthesis gene (glnA) were analyzed; inulin addition upregulated these key genes. Without exogenous glutamate, strain NX-2S could produce 6.85±0.22g/L of γ-PGA during fermentation. Exogenous glutamate greatly enhances the γ-PGA yield (39.4±0.38g/L) and productivity (0.43±0.05g/L/h) in batch fermentation. Our study revealed a potential method of non-food fermentation to produce high-value products.
本研究旨在开发非食品发酵工艺，利用新型解淀粉芽孢杆菌 NX-2S 来经济有效地生产聚-γ-谷氨酸（γ-PGA）。该新分离株比其他碳水化合物更有效地同化菊粉，而无需水解处理。为了研究菊粉对γ-PGA 生产的影响，分析了γ-PGA 合成酶基因（pgsB、pgsC、pgsA）、调控基因（comA、degQ、degS）和谷氨酸生物合成基因（glnA）的转录水平；菊粉的添加上调了这些关键基因。在没有外源谷氨酸的情况下，菌株 NX-2S 可以在发酵过程中生产 6.85±0.22g/L 的 γ-PGA。在分批发酵中，外源谷氨酸大大提高了 γ-PGA 的产量（39.4±0.38g/L）和生产效率（0.43±0.05g/L/h）。本研究揭示了一种利用非食品发酵生产高价值产品的潜在方法。
