1株解淀粉芽胞杆菌的常压室温等离子诱变及其发酵优化

Plasma Mutagenesis of a Bacillus amyloliquefaciens Strain under Atmospheric Pressure and Its Fermentation Optimization

为提高解淀粉芽胞杆菌(Bacillus amyloliquefaciens)TXM-A2对镰刀菌的抑菌作用,利用常压室温等离子(Atmospheric Room Temperature Plasma,ARTP)诱变技术处理菌株TXM-A2,以禾谷镰孢菌(Fusarium graminearum)为筛选指示菌,获得1株诱变株AR7,其对禾谷镰孢菌的抑制率提升了33.15%。经过5次传代培养,该诱变株的遗传稳定性良好。以诱变株的OD 600及无菌滤液对尖孢镰刀菌(Fusarium oxysporum)的抑制作用为检测指标,采用单因素试验优化发酵培养基,最优配方为葡萄糖10 g/L,酵母浸粉25 g/L,NaCl 5 g/L,优化后OD 600由3.250增加至5.543,对尖孢镰刀菌的抑菌直径由2.833 cm增加至3.027 cm。进一步对诱变株进行不同转速条件5 L罐分批发酵,最大活菌数可达1.65×10^(9)cfu/mL。利用ARTP技术筛选的诱变株对镰刀菌有较好拮抗作用,扩大培养后活菌数上升,可为生物防治剂开发提供参考。

In order to improve the inhibition of Bacillus amyloliquefaciens TXM-A2 against Fusarium spp.this study adopted atmospheric room temperature plasma(ARTP)mutagenesis technology to treat strain TXM-A2,and F.graminearum was used as a screening indicator to obtain a mutant strain AR7,and its inhibition rate against F.graminearum increased by 33.15%.After 5 subcultures,the genetic stability of the mutant strain was good.Taking the mutagenic strain′s OD 600 and sterile filtrate′s inhibitory effect on F.oxysporum as the detection index,a single factor experiment was used to optimize the fermentation medium,the optimal formula was glucose 10 g/L,yeast powder 25 g/L,NaCl 5 g/L,after optimization,the OD 600 increased from 3.250 to 5.543,the inhibition diameter of F.oxysporum increased from 2.833 cm to 3.027 cm.The mutant strains were further fermented in batches in 5 L tanks with different rotation speeds,and the maximum number of viable bacteria was as high as 1.65×10^(9) cfu/mL.The mutagenized strains screened by ARTP technology have a good antagonistic effect on F.oxysporum,and the number of viable bacteria increased after expansion of the culture,which can provide theoretical references for the development of biological control preparations.