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

Abstract:

[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.