Screening Of The Fermentation Detoxication Strains With Castor Meal And Its Detoxicating Analysis

Castor bean meal is a by-production after oil extraction, it contains rich prtein.However, the potential of castor bean meal for animal feed industry is limited by the presence of harmful components:ricinine、allergen、hemagglutinins and ricin.So, it is a good sources to develop.A microorganism with the detoxification effect of ricinine and allergen were isolated from natural moldy castor bean meal by using the plate separation method.The effects of the rate of ricinine and allergen detoxification and the change of nutrition elements such as fermentation medium composition and fermentation conditions were studied under the solid-state fermentation,and the fermentation conditions were optimized by using orthogonal test.The mainly results were as follows:1. A fungus with the detoxification effect of ricinine and allergen was isolated from natural moldy castor bean meal, named as MJ-7, and was primarily identified by micro-morphology and the special structure observed.The results showed that strain MJ-7has the typical special structure such as rhizoids, stolon and typical sporangium. The strain MJ-7was primarily identified as Rhizopus.2. Effects of fermentation conditions such as carbon sources,nitrogen sources,inorganic salt,the ratio of substrate to water,fermentation temperature,the initial pH value,inoculum,fermentation time etc on the degradation rate of ricinine and allergen and the rate of crude protein and free amino acid increased were studied by using single-factor experiment.The results showed that the optimal fermentation conditions were as follows:the ratio of castor bean meal and wheat bran was95:5, glucose1.5%, KH2PO40.25%, CaCO30.4%, the ratio of mateial to water was1:0.8,fermentation temperature28℃, initial pH value6.5, inoculum size12%, fermentation time6d. Under these conditions，the degradation rate of ricinine and allergen reached87.79%and95.15%, the rate of crude protein and free amino acid increased reached5.94%和7.32%.3. The optimal fermentation conditions of solid-stated fermentation were optimized by using orthogonal experiment.The results showed that the optimal fermentation conditions were:the ratio of mateial to water was1:0.8,fermentation temperature28℃, initial pH value7.0, inoculum size10%.under these conditions, the degradation rate of ricinine and allergen reached89.56%and96.79%. The study provided reference frame for the castor bean meal microbial detoxification.