Horizontal metaproteomics and CAZymes analysis of lignocellulolytic microbial consortia selectively enriched from cow rumen and termite gut

Abstract

Selectively enriched microbial consortia are potentially useful for the conversion of lignocellulose (LC) into biofuels and commodity chemicals. Consortia are also of interest to elucidate the roles of individual microorganisms and the dynamics of enzymes involved in LC deconstruction. Using metaproteomics, 16 S rRNA gene amplicon sequencing and multivariate discriminant analysis, we revealed the temporal dynamics of microbial species and their proteins during anaerobic conversion of LC by microbial consortia derived from cow rumen (RWS) and termite gut (TWS) microbiomes. Bacteroidetes (Bacteroidota), Firmicutes (Bacillota) and Proteobacteria (Pseudomonadota) phyla were dominant, irrespective the inoculum origin, displaying functional complementarities. We identified a large variety of carbohydrate-active enzymes, distributed in 94 CAZy families, involved in biomass deconstruction. Additionally, proteins involved in short chain fatty acids biosynthesis were detected. Multivariate analysis clearly differentiates RWS and TWS metaproteomes, with differences originating in the initial inoculates. Further supervised discriminant analysis of the temporal succession of CAZymes revealed that both consortia consume easily accessible oligosaccharides during the early stage of incubation, degrading more complex hemicellulose and cellulose fractions at later stages, an action that pursues throughout the incubation period. Our results provide new insights regarding the functional roles and complementarities existing in lignocellulolytic consortia and highlight their potential for biorefinery applications.