Abstract:The YPG medium containing acetic gossypol was used for the gossypol-degrading strain screening,A strain of Candida tropicalis JD-9 with high efficiency of gossypol-degrading was screened out.The methods of single factor experiments,fractional fractional factorial experimental design and central composite experimental design were used to optimize the process parameters for detoxification of gossypol in cottonseed meal by candida tropicalis JD-9 during solid substrate fermentation.The optimum fermentation conditions were as follows:inoculums level of JD-9(Candida tropicalis)4.42%,inoculums level of JD-13(S.carlsbergensis)0.56%,inncubation time 48h,incubation temperature 30¡æ,ratio of material to water 1:0.8.Under the optimum conditions,the content of gossypol reduced from 987.4mg/kg to 85.9mg/kg,and the detoxification efficiency was up to 91.3%.