Transcriptomics analysis reveals the high biodegradation efficiency of white-rot fungus Phanerochaete sordida YK-624 on native lignin

Background Lignocellulosic biomass is an organic matrix composed of cellulose, hemicellulose, and lignin. In nature, lignin degradation by basidiomycetes is the key step in lignocellulose decay. The white-rot fungus Phanerochaete sordida YK-624 (YK-624) has been extensively studied due to its high lignin degradation ability. In our previous study, it was demonstrated that YK-624 can secrete lignin peroxidase and manganese peroxidase for lignin degradation. However, the underlying mechanism for lignin degradation by YK-624 remains unknown.Results Here, we analyzed YK-624 gene expression following growth under ligninolytic and nonligninolytic conditions and compared the differentially expressed genes in YK-624 to those in the model white-rot fungus P. chrysosporium by next-generation sequencing. More ligninolytic enzymes and lignin-degrading auxiliary enzymes were upregulated in YK-624. This might explain the high degradation efficiency of YK-624. In addition, the genes involved in energy metabolism pathways, such as the TCA cycle, oxidative phosphorylation, lipid metabolism, carbon metabolism and glycolysis, were upregulated under ligninolytic conditions in YK-624.Conclusions In the present study, the first differential gene expression analysis of YK-624 under ligninolytic and nonligninolytic conditions was reported. The results obtained in this study indicated that YK-624 produces more energy- and lignin-degrading enzymes for more efficient lignin biodegradation.

Enzymatic Textile Dyes Decolorization by In vitro and In silico Studies

Background:Laccase, a multicopper oxidoreductase (EC: 1.10.3.2), is a widely used enzyme in bioremediation of textile dye effluents. Fungal Laccase is preferably used as a remediating agent in the treatment and transformation of toxic organic pollutants. In this study, crude laccase from a basidiomycetes fungus, Phanerochaete sordida, was able to decolorize azo, antroquinone and indigoid dyes. In addition, interactions between dyes and enzyme were analysed using molecular docking studies.Methods:In this work, a white rot basidiomycete’s fungus, Phanerochaete sordida, was selected from forest soil isolates of Eastern Ghats, and Tirumala and lignolytic enzymes production was assayed after 7 days of incubation. The crude enzyme was checked for decolourisation of various synthetic textile dyes (Vat Brown, Acid Blue, Indigo, Reactive Blue and Reactive Black). Molecular docking studies were done using Autodock-4.2 to understand the interactions between dyes and enzymes.Results:Highest decolourisation efficiency was achieved with the crude enzyme in case of vat brown whereas the lowest decolourisation efficiency was achieved in Reactive blue decolourisation. Similar results were observed in their binding affinity with lignin peroxidase of Phanerochaete chrysosporium through molecular docking approach.Conclusion:Thus, experimental results and subsequent in silico validation involving an advanced remediation approach would be useful to reduce time and cost in other similar experiments.