초록
<P><B>Abstract</B></P> <P>Spent ammonium sulphite liquor (SASL) is the main effluent from the ammonium sulphite pulping process, and contains amounts of lignocellulosic oligomers, monosaccharides and ammonium salts. The effect of continuous SASL-feeding on cellulase production by <I>Penicillium oxalicum</I> was studied. With a rate-varying feeding strategy, the maximal filter paper enzyme (FPase) activity reached 17.66U/mL at 144h, and the specific FPase activity increased from 1.74U/mg (without SASL) to 2.40U/mg. Accordingly, the glucan hydrolysis conversion of delignified corn cob residue by the enzymes from continuous SASL-feeding fermentation was significantly higher than that without SASL at equal protein loadings. Comparative proteomic analysis demonstrated that the proteins involved in lignocellulose degradation were specifically up-regulated in the crude cellulase with SASL-feeding. The obtained crude enzyme was efficient in the hydrolysis of pulping products, with a glucan conversion of 81.87% achieved after 72h saccharification of ammonium sulphite pulp.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Fermentation with continuous feeding SASL improved cellulase production. </LI> <LI> The maximum FPase reached 17.66U/mL using a multi-stage feeding strategy. </LI> <LI> Comparative proteomic analysis showed that SASL induced cellulases synthesis. </LI> <LI> The SASL-induced cellulase could hydrolyze ammonium sulphite pulp efficiently. </LI> </UL> </P>