Abstract

The natural lignocellulose degrading capabilities of extracellular enzyme secreted by a composite microbial system XDC-2 were studied. Peptone cellulose solution (PCS) medium was beneficial to the degradation of lignocellulosic materials and ATCC 1053 medium promoted enzyme production of XDC-2. The exocellular xylanase activities of the crude enzymes were stable below 40°C. The crude enzyme has an effective capability of degrading natural lignocellulose, especially natural hemicellulose. The corn stalk core and rice straw lost 21.1 and 11.9% of its weight, respectively, after 48 h hydrolysis by the crude enzyme, and the weight loss of hemicellulose of corn stalk core and rice straw was 84.7 and 27.8%, respectively. Qualitative scanning electron microscopes (SEM) images indicated that after 48 h crude enzymes hydrolysis at 35°C, the material structure was modified. The production of the soluble carbohydrates was up to 2, 400 mg·L^-1 for corn straw and 1, 300 mg·L^-1 for rice straw. It would hold the potential of further development and application of XDC-2 with the ability to hydrolyze natural lignocelluloses and release soluble carbohydrates.

Key words: Composite microbial system, lignocellulose degradation, exocellular xylanase, hydrolysis ability.