传统筛选与常压室温等离子体诱变接续选育高产吡嗪类物质菌株及应用OA

The integration of conventional screening techniques and ARTP mutagenesis presents a prominent advantage for strain im-provement in the Baijiu fermentation industry.This study focused on various Daqu samples from Sichuan-producing regions.Through a com-bined approach of traditional screening and ARTP mutagenesis,high-yield pyrazine-producing strains were successfully bred and systemat-ically characterized.Their practical application in actual Baijiu fermentation using fermented grains was further investigated.Results showed that the initially isolated strain X-23 was identified as Bacillus subtilis via molecular biology methods-a Gram-positive bacterium capable of producing 85.48 mg/kg of pyrazines.After ARTP mutagenesis,the mutant strain M-6 exhibited significant morphological chan-ges under scanning electron microscopy and showed enhanced protein metabolism capabilities.Specifically,gelatin liquefaction and mal-onate test results turned from negative to positive.Under solid-state sorghum culture conditions,the total volatile compound production by M-6 increased by 140.26％compared to the wild strain,with pyrazine yield reaching 1 240.36 mg/kg-14.51 times higher than that of the original strain.The mutant also produced a more diverse profile of pyrazine compounds.Fermentation validation in actual grain compost further confirmed that inoculation with M-6 led to the detection of dimethyl-pyrazine[(21.37±2.82)mg/kg],trimethyl-pyrazine[(27.23±1.95)mg/kg],and tetramethyl-pyrazine[(60.71±1.42)mg/kg].Thus,M-6 demonstrates excellent pyrazine synthesis ca-pacity in fermented grain systems.This study provides novel microbial resources and a theoretical foundation for enhancing product quality and innovating brewing processes in China's traditional Baijiu industry.