Medium optimization for exopolysaccharides production by Bacillus Zhangzhouensis BZ 16 strain isolated from Khnifiss Lagoon

Abstract

The increased demand for natural polymers for diverse industrial applications in last years has led to a renovated interest in exopolysaccharides (EPS) production by microorganisms. Ecological roles of EPS especially for those isolated from extreme habitats such as hypersaline ponds have been reported in several studies. A moderate halophilic strain producing exopolysaccharide (EPS) has been isolated earlier. However, the EPS production of the strain (2 g/L) was relatively low to exploit it at the industrial level. In the present work, the strain was identified as Bacillus zhangzhouensis and named as BZ 16 and the optimal medium was studied to boost the EPS production. Maximum EPS production was obtained in medium with 125 g/L sucrose, 30 g/L yeast extract. Phosphate source inhibited EPS production even if it increased the growth. Under optimal medium composition, EPS was produced at 12.37 g/L, which was 6 times greater than the production yield achievable without optimizing conditions.