黑曲霉M_1M_(15)M_(19)降解稻草秸秆的试验研究

Biodegradation of rice straw by aspergillus niger M_1M_(15)M_(19)

分析黑曲霉 M1 M1 5M1 9在含不同浓度的 C源、N源稻草秸秆基质上培养 3 0 d过程中木质纤维素酶类和主要化学成分。结果表明 ,黑曲霉 M1 M1 5M1 9降解秸秆的最佳条件是低碳高氮 L CHN,降解秸秆中木质素的最佳条件是高碳低氮 HCLN,经过 2 5 d降解率分别为48.2 %和 2 0 .4%。秸秆降解过程中纤维素酶和半纤维素酶起到了决定性的作用 。

The present study is dealing with the activities of lignocellulolytic enzymes ( laccase, lignin peroxidases, manganese-dependent peroxidases, cellulase and hemicellulase ). It is aimed also to determine the content and their change of the main chemical constituents (cellulose, hemicellulose and lignin) in the process of cultivation, in which aspergillus niger M_1M_(15)M_(19) is cultivated in the solid media of rice straw supplemented with carbon and nitrogen source at 30 ℃. The results of our experiments indicate that the most appropriate condition of cellulose, hemicellulose and the rice straw biodegradation is low carbon and high nitrogen (LCHN). The activities of the lignocellulolytic enzymes and the biodegradation rate keep on changing with the extension of cultivation time. First of all, cellulase activity would reach their peak of 7.94u at LCHN conditions in 25 days of cultivation. Secondly, hemicellulase activity would reach the peak of 53.09u at LCHN conditions in 15 days of cultivation. Thirdly, lignin peroxidases activity may reach the peak of 2 824.4u at high carbon and low nitrogen (HCLN) conditions in 10 days. Fourthly, manganese-dependent peroxidases activity would reach the peak of 6 880u at HCLN conditions after 20 days culturing. The most appropriate condition for rice straw lignin biodegradation is HCLN. After 30 days of cultivation, 68% of cellulose and 60.3% of hemicellulose will be biodegradated. 25 days later after the cultivation begins, 48.2% rice straw mass and 20.4% lignin will be biodegradated. In fact, cellulases and hemicellulases may have crucial influence on the biodegradation of rice straw, while lignin peroxidases and manganese-dependent peroxidases may also be of significant effect on the biodegradation of lignin in rice straw.