Potential biotechnological properties of an exopolysaccharide produced by newly isolated Bacillus tequilensis-GM from spontaneously fermented goat milk

Abstract

In the present work, an exopolysaccharide (EPS) was produced by a newly isolated Bacillus tequilensis-GM ropy strain. Results showed that EPS-GM was produced simultaneously with the growth phase and reached its maximum (2.9 g/L) when sucrose was used as carbon source. According to GC-MS and HPLC-SEC results, the recovered EPS-GM was composed by fructose, glucose, mannose, galactose, galactosamine and N-acetyl-glucosamine, with high molecular weight ranging between 1.8 and 2.5 × 106 Da. Different properties of EPS-GM were tested. Results showed that crude EPS-GM has several potential features, including high thermostability evaluated by DSC (with a melting point of 222 °C), good emulsifying properties and stability at both neutral and acidic pH, and high capacities to adsorb heavy metal ions (94.96% of Fe2+, 97.66% of Zn2+ and 98.24% of Cu2+) making it promising to be used in different industrial fields.