Guo Lifei, Lu Liang, Wang Huichao, Zhang Xiaoxing, Wang Genan, Zhao Tingbin, Zheng Guobao, Qiao Changsheng
College of Bioengineering, Tianjin University of Science and Technology, Tianjin, 300457, China.
Tianjin Engineering Research Center of Microbial Metabolism and Fermentation Process Control, College of Biotechnology, Tianjin University of Science and Technology, Tianjin, 300457, China.
Microb Cell Fact. 2023 Feb 24;22(1):37. doi: 10.1186/s12934-023-02042-0.
Poly-γ-glutamic acid (γ-PGA) is biodegradable, water-soluble, environment-friendly, and edible. Consequently, it has a variety of industrial applications. It is crucial to control production cost and increase output for industrial production γ-PGA.
Here γ-PGA production from sugarcane molasses by Bacillus licheniformis CGMCC NO. 23967 was studied in shake-flasks and bioreactors, the results indicate that the yield of γ-PGA could reach 40.668 g/L in a 5L stirred tank fermenter. Further study found that γ-PGA production reached 70.436 g/L, γ-PGA production and cell growth increased by 73.20% and 55.44%, respectively, after FeSO·7HO was added. Therefore, we investigated the metabolomic and transcriptomic changes following FeSO·7HO addition. This addition resulted in increased abundance of intracellular metabolites, including amino acids, organic acids, and key TCA cycle intermediates, as well as upregulation of the glycolysis pathway and TCA cycle.
These results compare favorably with those obtained from glucose and other forms of biomass feedstock, confirming that sugarcane molasses can be used as an economical substrate without any pretreatment. The addition of FeSO·7HO to sugarcane molasses may increase the efficiency of γ-PGA production in intracellular.
聚-γ-谷氨酸（γ-PGA）具有可生物降解、水溶性、环境友好和可食用的特性。因此，它有多种工业应用。对于γ-PGA的工业生产而言，控制生产成本并提高产量至关重要。
本文研究了地衣芽孢杆菌CGMCC NO. 23967利用甘蔗糖蜜生产γ-PGA的情况，在摇瓶和生物反应器中进行实验，结果表明在5L搅拌罐发酵器中γ-PGA产量可达40.668g/L。进一步研究发现，添加FeSO·7H₂O后，γ-PGA产量达到70.436g/L，γ-PGA产量和细胞生长分别提高了73.20%和55.44%。因此，我们研究了添加FeSO·7H₂O后的代谢组学和转录组学变化。这种添加导致细胞内代谢物丰度增加，包括氨基酸、有机酸和三羧酸循环关键中间产物，同时糖酵解途径和三羧酸循环上调。
这些结果与从葡萄糖和其他形式生物质原料获得的结果相比具有优势，证实甘蔗糖蜜无需任何预处理即可用作经济的底物。向甘蔗糖蜜中添加FeSO·7H₂O可能会提高细胞内γ-PGA的生产效率。
