Characterization of Exopolysaccharide Produced by Lactobacillus casei AL15 Isolated from Sap of Arenga pinnata

Abstract

Exopolysaccharide (EPS) is a polymer of a reducing sugar which has a high molecular weight. This polysaccharide is usually produced by lactic acid bacteria, and has a very large usability for food products and pharmaceutical products. Lactobacillus casei AL15 is a type of lactic acid bacteria isolated from sap of Arenga pinnata and has a great potential to produce EPS. Productivity in producing EPS of L. casei AL15 in MRS broth medium is about 14.1 mg/L. Furthermore, component of carbon was a highest composition of the EPS tested by SEM. The image of SEM showed that the shape of EPS were round to ellipse shape with smooth surface texture and white yellowish color. The spectrum of FTIR produced the wavenumber in the range of 3338 cm^-1 – 1056 cm^-1. The spectrum indicated the presence of O-H in 3338.78 cm^-1, C-H in 2962.66 cm^-1, C=O in 1649,14 cm^-1 and C-O-C in 1056.99 cm-1. Those bonds indicated that EPS produced by L. casei AL15 was heteropolysaccharide (HePS), since the FTIR spectrum had a same spectrum with sucrose and glucose. This result was also supported by HPLC analysis, which showed that the hydrolyzed EPS was composed by sucrose and glucose. Overall results showed that L. casei EPS AL15 was HePS.

Keywords: characterization, exopolysaccharide, Lactobacillus casei AL15, Arenga pinnata.