Research of fermentation preparation technology and preliminary application for Deoxynivalenol-degrading direct inoculated microbial inoculum

Abstract

Deoxynivalenol(DON)，as a secondary metabolite of some fusarium species，has been harmful to the food and feed industry.To improve spore-producing ability of Bacillus subtilis，the fermentation pH，temperature，supplemental carbon source and duration of Bacillus subtilis that efficiently degraded DON were studied in 5L-quadruple fermenters.The best fermentation conditions were determined，the fermentation pH was controlled at 7.5 and the temperature was controlled by stages，kept at 37 ℃ for first 12 hours，then raised to 39 ℃ until the end; 10 g/L molasses was added once at the 12th hour，then the fermentation was terminated at the 30th hour.Under the optimal conditions，the number of spores could reach 2.9×1010 CFU/mL and the spores’ rate could reach 96.7%.The fermentation liquid were further prepared into direct inoculated microbial inoculum and applied to remove DON from grain processing by-products; Under the condition that dry matter content in the composite material culture medium was not more than 30%，and the inoculation amount of the bacterium preparation was more than 0.1%，DON in the grain by-products could be effectively removed by fermentation and the highest degradation rate could reach 98.8%.

Keywords

• deoxynivalenol
• bacillus subtilis
• optimization of fermentation conditions
• spores rate
• don detoxification of grain by-products