有机溶剂胁迫处理对菌株Bacillus subtilis OST23a产胞外多糖的影响

【目的】研究有机溶剂胁迫处理对菌株分泌胞外多糖的影响并确定最佳条件。【方法】利用分泌抗氧化活性胞外多糖海洋细菌Bacillus subtilis OST23a及其突变菌株UD292为出发菌株,在考察菌株有机溶剂耐受性的基础上,测定不同浓度正己烷胁迫处理不同时间后该菌株抗氧化胞外多糖产量。【结果】结果表明最佳胁迫处理浓度和时间分别为3%和6 h,此时Bacillus subtilis OST23a和菌株UD292胞外多糖分泌量分别从9.02 mg/L和43.92 mg/L显著提高到52.97 mg/L和201.81 mg/L,且胞外多糖的抗氧化性能无显著变化。Bacillus subtilis OST23a和菌株UD292连续传代试验结果表明菌株遗传性状较稳定。【结论】有机溶剂胁迫可以提高细菌分泌胞外多糖的能力,在微生物育种方面有潜在的应用。

Effects of n-hexane stress on secretion of antioxi-dant exopolysaccharides from marine strain Bacillus subtilis OST23a

Objective] In this paper, the effects of organic solvent stresses on the yield of antioxidant exopolysaccharide (EPS) from Bacillus subtilis was evaluated and the best condition was also determined. Methods] Marine strain Bacillus subtilis OST23a and mutant UM29, both with the ability to produce antioxidant exopolysaccharide (EPS), were used as the original strain. Based on the detection of the tolerance of the strains to the organic solvent, n-hexane was used to stress treatment. Effects of concentrations and treatment time of n-hexane on the exopolysaccharide excretion from Bacillus subtilis OST23a and strain UD292 were studied. Results] The productivity of the EPS of Bacillus subtilis OST23a and strain UD292 were 52.97 mg/L and 201.81 mg/L respectively after stress treatment with 3% n-hexane for 6 h. There was no significant difference in the antioxidation activities of the extracellular polysac-charides between strains stress with n-hexane and the original strains. Moreover, the continu-ous passage experiment showed that the strains have high genetic stability. Conclusion] The organic solvent stress could improve the productivity of the exopolysaccharide from bacteria, which possesses the potential application in microbial breeding.