An innovative co-fungal treatment to poplar bark sawdust for delignification and polyphenol enrichment

This work aims to demonstrate a new high-efficient way to lignin degradation plus polyphenol enrichment in poplar bark sawdust by a co-fungal treatment with white rot fungi of C. subvermispora, C. cinereus and P. ostreatus in an equal volume-ratio fermentation for three weeks. The results indicated that compared with any one of these fungi, over 50 % lignin-degradation and 6-fold polyphenol enrichment were achieved at the 12th day for the best performance by these mixed-fungi treatments. The polyphenol enrichments from the increasing amount of pmtocatechuic acid and caffeic acid-3-glucoside were confirmed by HPLC-ESI-QTOF-MS/MS and ATR-FT-IR, which facilitated the lignin-degradation in turn. They were potentially ascribed to an obvious improvement activity of ligninolytic enzyme (laccase, lignin peroxidase and manganese-dependent peroxidase) for the lignindegradation and beta-glycosidase action for flavonoid degradation, respectively. All above-mentioned results will provide a potential protocol for lignin degradation and polyphenol enrichment when the different fungi in coculture play a role in synergism.