Enhanced production of xylanase by Aspergillus carneus M34 in solid-state fermentation with agricultural waste using statistical approach

The production of a low molecular weight xylanase by Aspergillus carneus M34 was investigated in solid-state fermentation using agricultural waste as the substrate. Experimental designs were practiced for optimisation of the medium composition. When agricultural wastes of coba husk and corn steep liquor were used in the ratio of 4.5:0.5, a 22.5% increase of xylanase activity was observed compared with the medium containing only coba husk. The incubation time for xylanase production can be reduced from 12 days to six days by increasing the inoculum size to 2 x 10(7) spores mL(-1). The optimal media compositions were as follows by using statistical approach: coba husk/corn steep liquor (4.5/0.5); NH4NO3, 32.4 g L-1; CaCl2, 1.34 g L-1; MnSO4 center dot 7H(2)O, 0.0124 g L-1. Xylanase activity of 1721 U g(-1) substrate was obtained by A. carneus M34 in a six-day period at 30 degrees C, which was a 227% increase compared with that obtained before applying the Plackett-Burman and response surface methodology experimental design.