| To optimize the liquid fermentation medium and conditions for a phosphate-decomposing Bacillus strain YC4 isolated from aquaculture ponds, nutrient sources and major influencing factors were experimented under shake flasks to obtain their effects on the cell growth and spore formation and the growth curve of the strain was established. Theoptimal medium is determined to be composed of 10译of molasses, 5译of soybean protein powder, 5％of yeast extract, 5％of KH2PO4, 1.5％of MgSO4,15％of NaCl and 5％of corn steep liquor, and the optimal fermentation condition is 30益with initial medium pH of 7.0-7.5, inoculum size of 1%, and rotation speed of 200 r/min. The best ingathering time should be in 24 hours. Under the optimized fermentation medium and conditions, the biomass concentration reaches 1.23×109 CFU/mLand the production of spores is 1.01伊109 CFU/mL, both of which are apparently higher than the control experiment. |
