Study on solid-state fermentation of Aspergillus niger to produce flax-retting complex enzymes

Using wheat bran as the main material, the fermentation medium and fermentation conditions of Aspergillus niger HYA4 for the production of flax-retting complex enzymes were optimized by single factor and orthogonal test. The results showed that the optimal medium contained 10 g wheat bran, 2.5% soymeal, 3.5% NaNO3, 1.0% (NH4)2SO4 and 10 ml water. The optimal fermentation conditions were: 10g medium in 250 ml Erlen-meyer flask, initial pH 5.0～5.5, cultivation temperature 32℃, and fermentation time 96 h. Under above conditions, the activities of pectinase and xy-lanase reached 2215.48 U/g (dry starter) and 99.68 U/g (dry starter), respectively.