Cooperative Regulation And Control Of Ligninolytic Enzymes By Phanerochaete Chrysosporium During Inducing And Incentive In Lignin Biodegradation

Lignin is a major organic component of plants as well as cellulose and hemicelluloses,and a by-product of agriculture,wood hydrolyzing industry and paper-making industry,generally exists in municipal organic solid waste.It is well know that lignin is a kind of environmental pollution because many industrial enterprises are not taking full advantage of the large production lignin,and it pollutes the environment to varying degrees.Lignin degradation is a most important part of the world's carbon cycle.Lignin,as the most significant organic material,is hard to degrade due to its complex structure,but it can be easily resolved by microorganism which can produce ligninolytic enzymes in nature.These specific enzymes can fracture the lignin into pieces and oxidize the partial chemical bonds.According to the analysis of degradation product,the process of lignin degradation is demethylation and dehydroxylation,polyphenol ring opening and aliphatic hydrolysis.Ligninolytic enzyme system catalyzes lignin biodegradation,so the secretion and activity of ligninolytic enzymes is the key in lignin biodegradation.Currently,the studied of ligninolytic enzyme system is mainly focuses on application of LiP,MnP and laccase.However,it is not completely clear which substance or element can induce ligninolytic enzymes,and few understanding about all induced mechanism.In the study,we researched the effect of four different inducers to ligninolytic enzyme activity by ultraviolet spectrophotometric analysis,CG/MS analysis and electron microscopes scan analysis.Under the condition of liquid fermentation,the results showed that the optimum concentration of Cu2+ was 0.05 mmol/L,the optimum concentration of Mn2+ was 0.2 mmol/L,the optimum concentration of Veratryl alcohol was4 mmol/L,the optimum concentration of Tween 80 was 0.1%,the most appropriate pH was 4.5 and the most appropriate temperature was 37?.We also researched the different inducers affecting mechanism of ligninolytic enzymes biodegradating alkali-remove lignin and found that the right amount of inducers can promote the activity of ligninolytic enzymes and improve lignin biodegradation efficiency.We combined these optimum conditions and cultured Phanerochaete chrysosporium.Test results holded that compared with blank control,the activity of LiP increased 2.5 fold,the activity of MnP increased 4 fold and the activity of laccase increased 3 fold.