Study On Solid-state Fermentation Conditions Of Bacillus Natto And Its Application

The fermentation cultural medium and solid-state fermentation conditions, preparation of drying technology and application in broiler breeding are studied with Bacillus natto as fermenting strain in this study.The main contents and conclusions are showed as follows:(1) Optimization of solid-state fermentation conditions of Bacillus natto. Effects of the fermentation conditions on spore number such as an medium component,the ratio of substance to water,inoculation,initial pH value,medium loading,cultural time and so on were studied by using wheat bran and zeolite powder as the main raw material,and the fermentation conditions were determined by using response surface experiment with spore number as index.The results showed that the optimal fermentation conditions were as follows:wheat bran 58%,zeolite powder 34%,soybean cake powder 5.35%,glucose 2%,KH2PO4 0.5%,MgSO4·7H2O 0.15%,the initial pH value 7.56,the ratio of substance to water 1:1.1,50.39g/250mL triangle flask,inoculation4.16%,fermentation time 4 d.Under these conditions,the number of spore reached 6.48×1010cfu/g.(2) Study on Bacillus natto preparation drying process. The effects of drying protective agent, addition amount, drying temperature, protective agent on the survival rate were studied. The results showed that the suitable protective agent was trehalose, the addition amount was 4%, the content of water was dry and moisture content was 10% at 60? before drying.Under these conditions,the survival rate of cell reached 95.36%.The number of viable bacteria was not significantly decreased by continuous storage 70d at 30?.(3 Preliminary study on the application of Bacillus natto preparation. The experimental results showed that the average daily weight than the control group increased 11.91%, average weight increased by 11.18%. The rate of death was only 0.43%, decreased 111.16% compared with the control.But slaughter rate and breast muscle rate was not significant compared the control group. The cost of breeding feed was decreased by 13.91% compared with the control adding 0.2% Bacillus natto preparation in diets,which has good economic benefit.