Chemical analysis of EPS produced by Lactobacillus spp.

초록

In a previous study, we have isolated Lactobacillus spp. from healthy human and examined various characteristics such as antimicrobial substance production and exopolysaccharide (EPS) production. In this study, we have selected L. paracasei KLB58 and L. furmentum CJS101 having high EPS productivity for chemical analysis of their EPS1). First, we have tested various growth conditions for maximum EPS production using a modified semi-defined medium (mSDM)2). The highest EPS production was found to occur at 20 oC during 44 hr static cultivation. The glucose concentration which gave the highest EPS production was 20 g/L. Also, the highest EPS was produced at pH 5.5. In addition, we attempted to determine molecular weight (MW) and monosaccharide composition of the EPS by using MALDI-TOF, GC/MS3) and HPLC4). The estimated MW was found to be 2,300 dalton. Monosacharide of KLB58's EPS was found to consist of arabinose, xylose, glucose, fructose, and galactose whereas CJS101 contains ribose, mannose and tallose additionally. Further chemical analysis is under way.