Multi-omics analysis reveals the carbohydrate-active enzyme repertoire involved in degrading complex arabinoxylans in Penicillium parvum 4-14.

BACKGROUND: Corn bran arabinoxylan (CBAX) is one of the most structurally complex xylans in nature. The bioconversion of CBAX into value-added products remains challenging because the substrate is resistant to pure xylanases and commercial enzyme cocktails. The carbohydrate-active enzymes (CAZymes) of Penicillium parvum 4-14 have been shown to efficiently hydrolyze CBAX. This study aimed to investigate the expression patterns and functional roles of CAZymes involved in the degradation of complex arabinoxylans in the fungus using transcriptomic and proteomic technologies. RESULTS: P. parvum 4-14 grew on CBAX and corn cob arabinoxylan (CCAX) with different substitution patterns and produced secretomes with varied compositions. The CBAX- or CCAX-induced fungal secretomes showed similar ratios (76.2% and 75.1%) on monosaccharide release from CBAX, but the former has a 12% higher ratio on monosaccharide release from CCAX than the latter. Integrated transcriptomic and proteomic analyses revealed distinct patterns of functional gene expression and CAZyme secretion in P. parvum cells induced by the two types of arabinoxylans, implying that the fungus has a complex regulatory system for CAZyme synthesis. A total of 26 CAZymes were inferred to be involved in the degradation of CBAX on the basis of multi-omics data and substrate structures. At the same fungal growth stage (48 h), 24 of these 26 CAZyme showed 0.42- to 5.74-fold higher gene transcription levels under CBAX culture than under CCAX culture. CONCLUSIONS: Different sources of arabinoxylans significantly affect the production of extracellular CAZymes in P. parvum. These findings are valuable for understanding the key CBAX-degrading enzymes and engineering tailored enzyme systems to valorize complex hemicelluloses.