Study On Exopolysaccharide Production And Function Of Bacillus Licheniformis TS-01

Bacillus licheniformis TS-01 is known as probiotic, used for therapy and prophylaxis of gastrointestinal disorders in both humans and animals, but the mechanism has been not clear. In this paper, I studied the fermentation and extration conditions, the method of protein removal, function on exocelluar polysaccharide, while tried to discover the mechanism.The results indicated that the optimal fermentation medium contains corn powder 4%; soybean meal 2%; corn steep liquid 0.3%; CaCl2 0.05%; K2HPO4 0.2%I; nitial pH 7; seed cuiture time 16h; inoculum size 5%., while live cell concentration and exopolysaccharide production in fermentation broth got maximum level. Certain level of dissolved oxygen was kept by controlling liquid fermentation medium volume and stirring rate, and can affect production of exopolysaccharide. a -amylase and proteinase produced by Bacillus licheniformis TS-01 could affect production of exopolysaccharide. When alcohol density of fermentation supernatant was 50% and 70%, two kinds of water-solubility polysaccharide can be acquired.In Sevag method, optimal condition was that matching of exponent/chloroform-butanol was 4:1, abstracting time was 5 minute. When enzymatic method was maked, it was better using 2.0U/mg trypsin for 4 h treatment. Compared to Sevag method, enzymatic method was better, but the operation of enzymatic method was more complicated and takes longer time.IC50 (density of inhibition rate 50%) of both polysaccharide solutions was aimost 3.2×10-4 g/mL.It showed that both polysaccharide had strong scavenging effects on DPPH radical.Both polysaccharide solutions(5mg/mL) could increase activity of SOD of fermentation supernatant(P<0.01).The results showed that both polysaccharide had antioxidative activity.The proliferation and transformation of T lymphocyte and B lymphocyte were detected with MTT colorimetric assay.The results showed that both polysaccharide solutions could advance growth of T lymphocyte and B lymphocyte, and indicated that both polysaccharide could increase immune activity.The experimental results showed that both polysaccharide didn't have bactericidal activity to pathogen.Low using rate of pathogen to exopolysaccharide resulted low reproduction velocity of pathogen.