Efficient Breeding of Cyclic Lipopeptide Producing Bacillus velezensis G-1 by Mutagenesis and Its Antifungal Activity Against Alternaria alternata

In order to improve the cyclic lipopeptide production of wild-type Bacillus velezensis G -1 and reduce the production cost, Alternaria alternata was used as the target, cheap rapeseed meal was used as the nitrogen source, and antifungal activity was used as the evaluation index. The effects on the synthesis of cyclic lipopeptides in B. velezensis G -1 was studied by single and compound mutagenesis methods of ultraviolet, microwave, ARTP(atmospheric room temperature plasma), NTG (nitroso guanidine), DES (diethyl sulfate) and EMS (ethyl methylsulfonate) mutagenesis. The aim was to establish an efficient mutagenesis method for high-yield cyclic lipopeptide mutants of B. velezensis G -1 and to select high-yield strain with rapeseed meal as nitrogen source. The results showed that the forward mutation rates of chemical mutagenesis were significantly higher than those of physical mutagenesis in six kinds of single mutagenesis methods. The forward mutation rate of chemical mutagenesis was higher for NTG and EMS, which were 59. 97% and 59. 40%, respectively. In physical mutagenesis methods, ARTP had a higher forward mutation rate of 31. 37% . The combined treatment of NTG 150 滋g / mL, EMS 0. 6 mol / L, and ARTP 160 s significantly increased the forward mutation rate of B. velezensis G -1. A high-yield cyclic lipopeptide mutant selected from the compound mutagenic strain could increase the production of cyclic lipopeptide by 2. 33 times. The antifungal activity in vitro and in vivo increased by 52. 20% and 96. 55%, respectively. In this study, the combined mutagenesis method of NTG + EMS + ARTP could successfully obtain the B. velezensis G -1 mutant with high-yield cyclic lipopeptide, and further selected out mutants with high-yield cyclic lipopeptide by rapeseed meal. This study laid a theoretical foundation for the industrial application of the high-yielding B. velezensis G -1 mutants and its cyclic lipopeptides in the prevention of A. alternata infection after fruit and vegetable harvest. © 2025 Beijing Technology and Business University, Department of Science and Technology. All rights reserved.