Unravelling the enzymatic wood decay repertoire of Cerrena zonata: A multi-omics approach

Abstract

Lignocellulosic biomass (LCB), such as wheat straw, bagasse, or wood, is a cost-effective, sustainable carbon source but remains challenging to utilize due to the recalcitrance of lignin, which hinders efficient carbohydrate hydrolysis. Effective LCB degradation demands a wide range of enzymes, and commercial enzyme cocktails often require physical or chemical pretreatments. A fully enzymatic degradation could drastically improve the efficiency of these processes. Basidiomycota fungi naturally possess diverse enzymes suited for LCB breakdown. The white-rot fungus Cerrena zonata, a member of the phylum Basidiomycota, was analyzed for its Carbohydrate-Active Enzymes (CAZymes) using a multi-omics approach. Genomic and transcriptomic analyses of C. zonata identified 20,816 protein-encoding genes, including 487 CAZymes (2.3 %). Cultivating C. zonata with and without LCB addition revealed a total of 147 proteins, of which 36 were CAZymes (13 auxiliary activities (AA), 3 carbohydrate esterases, and 20 glycoside hydrolases). In accordance, laccase, manganese peroxidase (MnP) as well as versatile peroxidase (VP) activities were detected in the fungal culture supernatants. Furthermore, relevant enzymes were visualized via zymography. Consistent with these results, five putative peroxidases (AA2) and three putative laccases (AA1_1) were identified in all –omics dimensions. Further structure and sequence analysis of AA2 proteins supports that two proteins were classified as VPs and three as MnPs, based on their active and Mn^2 + binding sites. In summary, C. zonata possesses a broad enzyme spectrum expressed under varied conditions, highlighting its potential for identifying efficient lignin-degrading enzymes for enzymatic pretreatment of food industry side streams and other LCBs.