杂色云芝产木质纤维素酶及对稻草秸秆的降解

Production of Lignocellulolytic Enzymes and Rice Straw Biodegradation by Coriolus versicolor

在外加碳源和氮源的固态稻草秸秆基质上,对杂色云芝生长过程中产酶活性、主要化学成分及结构进行了分析.结果表明,不同的碳源、氮源浓度对所产酶活性有较大影响,除产半纤维素酶的最佳条件是低碳低氮外(0.15%的葡萄糖和0.03%氯化铵),其他如纤维素酶、木质素过氧化物酶、锰依赖过氧化物酶和漆酶产生的最佳条件都是高碳低氮(2%的葡萄糖和0.03%氯化铵).各种酶在稻草秸秆的降解中起着关键作用,酶活性直接影响主要化学成分的降解率.纤维素和半纤维素的降解对木质素的降解有明显的促进作用.经过32d的培养,稻草秸秆中纤维素、半纤维素和木质素的降解率分别为65.39%,45.11%和39.16%.经过降解,秸秆结构发生了明显的变化.

Lignin biodegradation has important significance for environmental protection and resource usage. In the present work, Coriolus versicolor was cultivated in the solid media of rice straw supplemented with glucose and ammonium chloride. The activities of lignocellulolytic enzymes and the contents of main chemical constituents were determined during the process of culturing. The straw structure was determined through scanning electron microscope and Fourier-transform infrared spectroscopy. The results show that enzyme activity is affected by concentrations of carbon and nitrogen sources. The most suitable condition for production of cellulases, lignin peroxidases, manganese-dependent peroxidases, laccases is high carbon and low nitrogen （glucose 2%, ammonium chloride 0.03%）, while the one of hemi-cellulases is low carbon and low nitrogen （glucose 0.15%, ammonium chloride 0.03%）. The ernzymes have crucial effect on the biodegradation, and the rate of biodegradation is directly influenced by the enzyme activities. Biodegradation of cellulose and hemi-cellulose significantly accelerates the biodegradation of lignin. 65.39% of cellulose, 45.11% of hemi-cellulose and 39.16% of lignin in rice straw are biodegradated after 32 d cultivation. Structure of rice straw has changed evidently after biodegradation.