枯草芽孢杆菌ZX-11培养条件及抑菌性能研究

Culture conditions and antibacterial property of Bacillus subtilis ZX-11

以大肠杆菌(Escherichia coli)为指示菌,抑菌活性为主要考察指标,优化枯草芽孢杆菌(Bacillus subtilis)ZX-11的培养条件,并对其代谢产物的抑菌谱及抑菌特性进行研究。结果表明,菌株ZX-11的菌体生长和抑菌活性具有半偶联特性,确定最优初始pH值为7.0,接种量为4%,同时发现,适宜菌体生长和抑菌物质合成的最适温度和转速不一致。基于此,提出两阶段培养模式:发酵0~12 h,37℃、210 r/min条件下培养,使菌体快速繁殖;发酵12 h后,切换为31℃、240 r/min,强化抑菌物质合成。在此条件下,菌株ZX-11对E.coli的抑菌性能(抑菌圈直径30 mm)比优化前、单一培养模式31℃、210 r/min,31℃、240 r/min,37℃、210 r/min,37℃、240 r/min分别提高50%、15%、7%、20%和11%。菌株ZX-11的代谢产物具有较广的抑菌谱,具有较强的耐酸、耐碱、耐高温能力,且对蛋白酶具有一定的稳定性。

The culture conditions of Bacillus subtilis ZX-11 was optimized with Escherichia coli as indicator and antibacterial activity as main inspection index,and the antimicrobial spectrum and antibacterial property of its metabolites were studied.The results showed that the strain ZX-11 had the characteristics of semi-coupling between bacterial growth and antibacterial activity.The optimal initial pH and inoculum was 7.0 and 4%,respectively.It was also found that the optimal temperature and speed for bacterial growth and antimicrobial synthesis were inconsistent.Based on this,a two-stage culture pattern was proposed:fermentation for 0-12 h at the conditions of 37℃and 210 r/min to make the bacteria multiply rapidly,after fermentation 12 h,it was changed to 31℃and 240 r/min to enhance the synthesis of antibacterial substances.Under these conditions,the antibacterial performance of the strain ZX-11 against E.coli(inhibitory zone diameter 30 mm)was 50%,15%,7%,20%and 11%higher than that of before optimization and single culture mode 31℃and 210 r/min,31℃and 240 r/min,37℃and 210 r/min,37℃and 240 r/min,respectively.The metabolites of the strain ZX-11 had broad antibacterial spectrum,strong acid,alkali and high temperature resistance,and had certain stability to protease.