Abstract: Orange peels were fermented by Aspergillus niger to produce cellulase and amylase by solid state fermentation (SSF). The effects of orange peel and water contents in SSF medium, inoculum size and fermentation time on cellulose and amylase activities were explored by one-factor-at-a-time method. Based on the results obtained, the fermentation conditions for the production of cellulase and amylase were optimized by orthogonal array design to be orange peel content of 16 g, initial water content of 64 mL/100 g, inoculum size of 15% and fermentation time of 60 h. Under these fermentation conditions, the activities of cellulase and amylase were 1816 U/g and 196 U/g, respectively. This study suggests that solid state fermentation can provide a promising strategy for the production of cellulase and amylase from orange peels by Aspergillus niger.

Key words: orange peels, Aspergillus niger, solid state fermentation (SSF), cellulase, amylase