Highly efficient production and characterization of the exopolysaccharides from a thermotolerant Bacillus sp.

Abstract

Abstract One thermotolerant Bacillus strain SFLV-ZM107 which could produce large amounts of extracellular polysaccharides (EPS) at 50°C was identified as Bacillus licheniformis by 16S rDNA sequencing and physiological and biochemical experiments. The EPS was identified as levan fructan by monosaccharides determination, NMR, and FTIR. Strain SFLV-ZM107 can be grown in the range of 35–55°C and it is efficient to produce levan from 400 to 500 g l−1 of sucrose. The production of levan can reach 158 g l−1 in a 5 L tank fermentation with an initial sucrose concentration of 450 g l−1 at 50°C for 12 hours with a maximum productivity of 13.17 g l−1 h−1. To the best of our knowledge, the strains obtained in this study are the most productive and efficient, which has great prospects for industrial application.