Integrative omics analyses of the ligninolytic Rhodosporidium fluviale LM-2 disclose catabolic pathways for biobased chemical production.

Background: Lignin is an attractive alternative for producing biobased chemicals. It is the second major component of the plant cell wall and is an abundant natural source of aromatic compounds. Lignin degradation using microbial oxidative enzymes that depolymerize lignin and catabolize aromatic compounds into central metabolic intermediates is a promising strategy for lignin valorization. However, the intrinsic heterogeneity and recalcitrance of lignin severely hinder its biocatalytic conversion. In this context, examining microbial degradation systems can provide a fundamental understanding of the pathways and enzymes that are useful for lignin conversion into biotechnologically relevant compounds.

Results: Lignin-degrading catabolism of a novel Rhodosporidium fluviale strain LM-2 was characterized using multi-omic strategies. This strain was previously isolated from a ligninolytic microbial consortium and presents a set of enzymes related to lignin depolymerization and aromatic compound catabolism. Furthermore, two catabolic routes for producing 4-vinyl guaiacol and vanillin were identified in R. fluviale LM-2.

Conclusions: The multi-omic analysis of R. fluviale LM-2, the first for this species, elucidated a repertoire of genes, transcripts, and secreted proteins involved in lignin degradation. This study expands the understanding of ligninolytic metabolism in a non-conventional yeast, which has the potential for future genetic manipulation. Moreover, this work unveiled critical pathways and enzymes that can be exported to other systems, including model organisms, for lignin valorization.