Studying On The Extrapolysaccharides Of The Bacillus Subtilis B₁⑥ Strain

A relation model between viscosity of culture broth and extrapolysaccharides (EPS) concentration was established in this paper. The equation of it was "y = -15227x²+ 83156x -113523" and the correlation was up to 98%. There was a positive correlation existing between them but the using range of viscosity was limited for the deviation existed. It was also practicable to some extent to simplify the testing of EPS in fermentation.The conditions of fermentation and preliminary extracts of Bacillus subtilis B₁â‘¥strain were optimized including single factor and multifactor tests. The results showed that the best carbon source , nitrogen source and C/N ratio were as follows: sucrose, 3%; (NH4)₂SO₄, 1%; (C/N=3/1) and the optimized conditions of fermentation in orthogonal design L9(3⁴) was MgSO₄, 0.05%; Na₂HPO₄, 0.2%; NaH₂PO₄, 0.1%; CaCL2, 0.1%; MnSO₄, 0-0.1%; inoculation amount, 10-12%;pH7-7.5. Under this culture condition, the EPS content of the Bacillus subtilis B₁â‘¥strain was increased. In extracting process, the concentration of produced EPS was the highest when compressing temperature was 40℃, compressing ratio was 1:1.5 and alcohol concentration was 70% in fermentation. Further more, the influence order of them was compressing temperature>compressing ratio> alcohol concentration. The significant influent factor is compress's temperature.Two EPS components that were EPSI and EPSIIwere obtained after the preliminary extracts of the Bacillus subtilis B₁â‘¥strain pass through DEAE-52 column, the analyzed results of EPSI by paper chromatography and GC showed that EPSI did not include glucose,mannose,xylose,galactose,rhamnose and fucose and displayed only one drop in paper chromatography that did not correspond to Ara which was displayed in GC slightly. It was concluded that EPSI was composed by an unknown monosaccharide and mini-arabinose probably.