Genomic Insights into Catenovulum agarivorans YM01^T: Marine Biomass Conversion by Thermostable Agarases for Functional Food Applications

Marine bacterium Catenovulum agarivorans YM01^T exhibits notable carbohydrate-degrading activities and produces highly thermostable agarases. Comprehensive genomic and comparative analyses identified 15 agarase-encoding genes. Compared with other agar-degrading strains, YM01^T possessed a greater abundance of genes related to carbohydrate transport, metabolism, and signal transduction, underscoring its exceptional polysaccharide-degradation capacity. The thermostability of its agarases (e.g., GH50 YM01-5) suggests promising applications in industrial processes requiring high temperatures. Differential gene expression, pathway enrichment, and gene network analyses demonstrated that gene expression in YM01^T is modulated by agar, thereby enhancing carbohydrate metabolism. Such substrate-specific regulation aligns with the optimization of microbial enzyme yields in fermentation systems, critical for scaling up the production of food-grade enzymes. Among the 18 genes implicated in agarose metabolism, 10 were cloned, with three exhibiting agarolytic activity in vitro. Sequencing assigned these enzymes to the GH16 and GH50 families; they shared high similarity with reported bacterial agarases, indicating conservation in catalytic features. The GH50 agarase YM01-5 was purified and characterized to display exo-hydrolytic activity. Its catalytic properties, including substrate specificity and reaction products, were comparable to those of other GH50 agarases; neoagarobiose was the sole hydrolysis product. Additionally, YM01^T harbored 63 chemotaxis-associated genes, indicating its strong capacity to sense stimuli from the marine environment, which may enhance substrate utilization in controlled bioreactor systems. Collectively, these findings highlight the metabolic versatility of YM01^T, its critical role in the marine carbon cycle, and its potential as a biotechnological platform for use in sustainable food processing and marine biomass valorization.