Co-production of menaquinone-7 and poly-γ-glutamic acid by ARTP-induced mutagenesis in Bacillus natto
摘要
Bacillus natto (B. natto) can produce various secondary metabolites, notably the coagulation-promoting menaquinone-7 (MK-7) and the natural multifunctional biopolymer poly-γ-glutamic acid (γ-PGA). To enhance the economic feasibility of the fermentation process. In this study, the ability to synthesize MK-7 of B. natto ND-1 was enhanced through atmospheric pressure room temperature plasma (ARTP)-induced mutagenesis. Subsequently, we found a significant amount of γ-PGA in the fermentation product. Additionally, the fermentation medium and cultural conditions were rigorously optimized. An optimal medium composed of 70 g/L glycerol, 200 g/L soy peptone, 50 g/L yeast extract, and 0.04 g/L K₂HPO₄ was obtained by Orthogonal experimental design. Following 96 h of liquid-state fermentation without agitation, the concentrations of MK-7 and γ-PGA were 48.31 ± 3.17 mg/L and 92.53 ± 2.71 g/L, respectively. These results suggested that the co-production of MK-7 and γ-PGA has demonstrated bioactivity and stability, providing a theoretical foundation for their potential application in the domains of food, medicine, and nutraceuticals.