Production of poly-gamma-glutamic acid (gamma-PGA) from xylose-glucose mixtures by Bacillus amyloliquefaciens C1

文献类型： 外文期刊

第一作者： Sun, Jia-Dong

作者： Sun, Jia-Dong;Tang, Chen;Zhou, Jun;Wei, Ping;Yong, Xiao-Yu;Yan, Zhi-Ying;Wang, Ya-Jun;An, Wei

作者机构：

关键词： Poly-gamma-glutamic acid (gamma-PGA); Carbon catabolite repression (CCR); Xylose utilization; Corncob hydrolyte (CCH); Gene transcriptional level

期刊名称：3 BIOTECH （ 影响因子：2.406； 五年影响因子：3.203 ）

ISSN： 2190-572X

年卷期： 2021 年 11 卷 2 期

页码：

收录情况： SCI

摘要： Due to the promising applications, the demand to enhance poly-gamma -glutamic acid (gamma -PGA) production while decreasing the cost has increased in the past decade. Here, xylose/glucose mixture and corncob hydrolysate (CCH) was evaluated as alternatives for gamma -PGA production by Bacillus amyloliquefaciens C1. Although both have been validated to support cell growth, glucose and xylose were not simutaneously consumed and exhibited a diauxic growth pattern due to carbon catabolite repression (CCR) in B. amyloliquefaciens C1, while the enhanced transcription of araE alleviated the xylose transport bottleneck across a cellular membrane. Additionally, the xyl operon (xylA and xylB), which was responsible for xylose metabolism, was strongly induced by xylose at the transcriptional level. When cultured in a mixed medium, xylR was sharply induced to 3.39-folds during the first 8-h while reduced to the base level similar to that in xylose medium. Finally, pre-treated CCH mainly contained a mixture of glucose and xylose was employed for gamma -PGA fermentation, which obtained a final concentration of 6.56 +/- 0.27 g/L. Although the glucose utilization rate (84.91 +/- 1.81%) was lower than that with chemical substrates, the xylose utilization rate (43.41 +/- 2.14%) and the sodium glutamate conversion rate (77.22%) of CCH were acceptable. Our study provided a promising approach for the green production of gamma -PGA from lignocellulosic biomass and circumvent excessive non-food usage of glucose.

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