Optimization of Solid State Fermentation Process for Gossypol Detoxification in Heat Sterilized Cotton Seed Cake by Mixed Fungal Cultures

A solid state fermentation (SSF) process was optimized for gossypol detoxification in cottonseed cake (CSC) using mixed fungal cultures viz., Pleurotus sajor-caju with Saccharomyces cerevisiae and Candida tropicalis with S. cerevisiae. The effect of fermentation conditions such as initial moisture content, inoculum level, incubation temperature and period were tested for gossypol reduction in heat sterilized (HS) CSC. The results showed optimized parameters for gossypol detoxification in HS CSC were 70% moisture content, 15% inoculum level, 30° C incubation temperature and 48 h incubation period. The free gossypol (FG) detoxification rate was higher (83.6%) in P. sajor-caju with S. cerevisiae fermented HS CSC. The detoxification rate of bound gossypol (BG) was higher (63.3%) in C. tropicalis with S. cerevisiae fermented HS CSC. The maximum increase in crude protein (CP) (10.2%) and decrease in crude fibre (CF) (10.7%) was recorded in C. tropicalis with S. cerevisiae and P. sajor-caju with S. cerevisiae fermented HS CSC respectively.