Production and Partial Characterization of a Glycoprotein Bioemulsifier Produced by Lactobacillus plantarum subsp. plantarum PTCC 1896

Given the growing interest in the production of new and low cost bioemulsifiers, the rice and wheat bran and straw were investigated in this study for the production of bioemulsifier by Lactobacillus plantarum subsp. plantarum PTCC 1896 (probiotic). The strain produced bioemulsifier only in the rice bran hydrolysate medium. The bioemulsifier amount reached around 0.7 g L^-1 for 72 hours of fermentation. The new biomolecule was extracted, purified, and its structural and thermal properties were evaluated. The functional groups and the structure of the molecule were revealed by GPC, FT-IR, 1HNMR and 13CNMR techniques. The bioemulsifier was a water soluble extracellular high molecular weight ( 10^7 Da) α-glucan (81.74%) bound with protein (18.18%). Thermal behavior was studied using DSC and TG analysis. Thermal analysis showed the bioemulsifier broke down above 211.74°C, and the melting point was 182.0°C with the enthalpy value of 101.7 J g^-1. These results might provide incentives for the industrial production of the biodegradable and safe bioemulsifier introduced in this study, which seems to offer potential applications in the food and medical industries.