中国生物工程杂志

Fermentation conditions for the production of spores of Bacillus mucilaginosus mutant 021120 were optimized through the single factor and orthogonal experiments. The results showed that the biomass and formation of spores were obviously affected by carbonate, followed by nitrogen. Addition of CaCO3 and enhancing air flux notably promoted the formation of spores. The optimal culture medium was composed of 2% starch, 0.4% Yeast, 0.1% K2HPO4, 0.1％ MgSO4·7H20 and 0.5 ％CaCO3, pH7.5. 6% of the inoculum prepared with two-stage extensive culture was inoculated into a 70L fermentor. The fermentation was carried out with 2.0-2.5 vvm of air flux at 32℃ for 38-42h, and the spores of 9.80×108 cfu ml-1 was obtained. Under these optimal fermentation conditions, the capsule was successfully controled and the formation of the spores was effectively improved, thus the satisfying bacteial product was obtained.