Optimisation of fermentation medium for the detoxification of free gossypol in cottonseed powder byGeotrichum candidum G07 in solid-state fermentation with response surface methodology

Abstract

Plackett-Burman design and response surface methodology were adopted to optimise the fermentation medium for Geotrichum candidum G07 to detoxify free gossypol in cottonseed powder by the solid-state fermentation. Results showed that the optimum medium was composed (%, w/w) of 1.63 (NH 4 ) 2 SO 4 , 0.10 KH 2 PO 4 , 0.05 MnSO 4 , 0.1 MgSO 4 , 0.2 CaCl 2 and 62.19 initial moisture content. The residual free gossypol level decreased from 144.0 μg g −1 to 30.42 μg g −1 after incubating at 30 °C for 48 h in the optimised conditions and the detoxification efficiency reached 78.9%, which indicated that G. candidum G07 was a useful strain to detoxify free gossypol in cottonseed powder and the statistical methods adopted in this paper were effective and powerful. This study can contribute towards decreasing the residual level of free gossypol in cottonseed powder, and can benefit the full use the agricultural residue.