Screening Of Selective Lignin-degrading Microorganisms From Bamboo Stand Soils And Optimization Of Its Enxyme Production Conditions

In recent years,many years of management of intensive coverage,led to t different levels of degradation of the soil covered with bamboo in Lin'an.The reason is that,years of excessive organic matter have been inputed and lots of organic matter of fiber remnants accumulated in soil.Excessive amounts of organic residues whitch contains cellulose and lignin can lead to soil aggregate structure,chemical properties,and changing dramatically of population distribution of biology,which affect the normal growth of bamboo forest.While the annual forest cover up need a large amount of labor and the organic mulch cleaning is difficult.So that the organic matter in the forest land is naturally decomposed and degraded in the ground.The lignocellulosic material degradation need a long time in natural undition and the lignin is one of the most important obstacles in the whole degradation process.so that the high effective degradation strains screening from the bamboo forest environmental is the key to degrading lignin and no pollution in bamboo forest safety.Organic matter and soil samples in this study mainly come from the bamboo forest in Ling'an and surrounding areas,which used to find out effective degradation of lignin in bamboo environmental strains that promoting the recovery of lignocellulosic material in the forest and soil degradation.?1?85 strains were isolated from the samples collected in the enrichment by separation and qualitative screening steps.then 14 strains were primarily screened by the size of the ability to change color screened and through the determination of enzyme activity screening,strain 27-1 of high laccase was finally screened and its laccase activity,Mn catalase activity activity is94.39,34.87U,lignin is not detected catalase activity.?2?Based on morphological and microstructure observation of Strain 27-1,preliminarily identified as filamentous fungi of basidiomycetes strains.Through the determination and comparison of sequences of ITS fungi,the strain 27-1 belonged to basidiomycetes,Polyporaceae,Trametes,Trametes hirsuta.?3?To study the strain liquid fermentation conditions.Results showed that,the optimum culture conditions were pH 4.5,30?,glucose 10 g,L^-1,bran 15 g L^-1.Manganese catalase activity is not stable,generally between 2-5U.The laccase activity could reach 74.45 U,by adding a certain amount of copper salt,can greatly enhance the laccase enzyme activity.So the strain 27-1is a high laccase lignin degrading bacteria.Through the research on the degradation of rice husk and leaf of bamboo,we found that single laccase producing strains had a certain degree of difficulty when it degrade the rice husk lignin.However the degradation of bamboo leaves can be efficiently degraded and the weight loss rate is higher,which can be used for further study on the application of the experimental strains.