The production of a low molecular weight xylanase by Aspergillus carneus M34 was investigated in solidstate
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 2 107 spores mL1. The optimal media
compositions were as follows by using statistical approach: coba husk/corn steep liquor (4.5/0.5);
NH4NO3, 32.4 g L1; CaCl2, 1.34 g L1; MnSO47H2O, 0.0124 g L1. Xylanase activity of 1721 U g1
substrate was obtained by A. carneus M34 in a six-day period at 30 8C, which was a 227% increase
compared with that obtained before applying the Plackett–Burman and response surface methodology
experimental design.