Isolation and Characterization of s-Butanol Tolerant Microorganisms
s-butanol can be produced indirectly from biomass by fermentation. To construct recombinant strains producing s-butanol directly, microbes naturally with high tolerance to s-butanol are required for metabolic engineering. In this study, totally 30 s-butanol tolerant microorganisms were isolated from different environmental soil samples by screening and enrichment method. Among the isolates, strains S-2, S-9, S-24, and S-26 were able to tolerate 15 g/L s-butanol. Additionally, s-butanol tolerance mechanisms were also studied by quantitatively analyzing degradation ability of the isolates. The results indicated that strains S-9 and S-24 possessed relatively low levels of s-butanol degrading enzyme activity and might be used as native tolerant strains for metabolic engineering. Strain S-13 showed the highest s-butanol degradation efficiency (72.7 %) in LB medium, suggesting that strain S-13 disrupted s-butanol via a way of co-metabolism and suitable for bioremediation of the chemical under more complicated environments. Furthermore, the isolated strains were identified by comparative analysis of the 16S rRNA gene sequences.