Changes In Diversity Of Basidiomycete Laccase Genes In Four Typical Stages Of Agricultural Waste Composting

Composting, as an economic and effective technology for solid waste treatment,is one of important research subject. But the application of traditional composting arelimited due to the biodegradative recalcitrance of lignin in composting material. Sothe improvement of composting efficiency are important. Since microbial communityare responsible for organic matter degradation during composting, the study onmicrobial community succession is a basis of composting technology and theoryresearches. Laccases are well-characterized as extracellular enzymes involved inlignin decomposition. The inoculation with laccases or microorganisms producinglaccases has been widely used as a strategy that could potentially speed up thecomposting process and ultimately improve the quality of compost product. Thisstudy discussed changes in diversity of basidiomycete laccase genes in four typicalstages of agricultural waste composting and investigated the effects of basidiomyceteslaccase genes on enzymes activity and lignin degradation, physic-chemical parameterson basidiomycete laccase genes, respectively.The second section: The changes in diversity of basidiomycete laccase genes infour typical stages of agricultural waste composting were investigated by qPCR andsequencing. Gene libraries were constructed from samples collected from fourrepresentative stages during agricultural waste composting. Using specific degenerateprimers, researchers detected110distinct basidiomycete laccase gene types fromcompost samples. Marked fluctuations of the basidiomycete laccase gene communitywere observed during the composting. Laccase genes associated with mesophilicbasidiomycetous fungi dominate the clone library constructed from the samplesduring the thermophilic stage. Laccase genes were less abundant during thethermophilic stage than other stages. Lignin degradation and phenol oxidase activitywere linearly related to basidiomycete laccase gene abundance during the compostingexcept for the thermophilic stage, respectively. The temporal variation ofbasidiomycete laccase gene community composition was significantly related totemperature(18.9%, p=0.002), WSC(9.2%, p=0.002), and moisture content(5.3%, p=0.01).