Genetic analysis and preliminary determination of production of exopolysaccharide of Streptococcus thermophilus KLDS SM

In order to explore the ability of exopolysaccharide synthesis of Streptococcus thermophilus KLDS SM based on gene level, three aspects of sugar transport systems, sugar nucleotide synthesis and exopolysaccharide gene cluster structure were analyzed in detail.The results showed that the bacteria could transport glucose, lactose, sucrose, trehalose and mannose, had the enzymes for glucose, lactose, fructose, sucrose, trehalose and mannose metabolism. The bacteria had the potential for exopolysaccharide precursor synthesis, including UDP-glucose, UDP-galactose, UDP-N-acetyl glucosamine, UDP-galactofuranose and d TDP-rhamnose.Furthermore, sequence alignment analysis showed that the exopolysaccharide sequence of this bacteria had a high identity to that of strain ASCC 1275, and preliminary determination of exopolysaccharide yield was about 331 mg/m L.The results showed that the strain was a potential EPS producing strain and had great potential in industry.