Exopolysaccharide production by <i>Bacillus subtilis</i> NCIM 2063, Pseudomonas aeruginosa NCIM 2862 and Streptococcus mutans MTCC 1943 using batch culture in different media

Abstract

Three bacterial strains, Bacillus subtilis NCIM 2063, Pseudomonas aeruginosa NCIM 2862 and Streptococcus mutans MTCC 1943 were examined for their exopolysaccharide (EPS) producing ability at the laboratory level. Basal salts solution (BSS), minimal salts medium (MSM), nitrogen free medium (NFM), chemically defined medium (CDM), milk medium (MLM) and sewage from different areas were used as nutrient source individually to assess EPS production by the above mentioned bacterial strains. Nitrogen free medium favoured more EPS production (Mean: 217.13, minimum: 206.000 and Maximum: 226.000). The highest EPS production was recorded in P. aeruginosa (226 ìg ml-1) grown in nitrogen free medium followed by S. mutans and B. subtilis (220 and 206 ìg ml-1 respectively) in nitrogen free medium after 7 days of incubation at 37°C. Analysis of carbon source in sewage samples indicated the presence of reducing monosaccharides. The purified EPS was soluble only in water and was free from protein contaminants.