Genome-wide analysis of Flavobacterium strain YJ01 demonstrates abundant enzymes synergistically degrade diverse nature carbohydrates.

Aims: Flavobacterium strains are widely distributed in various environments and generally exhibit specialized roles in the degradation of complex organic substrates. To obtain a deeper understanding of their enzyme profiles, patterns of action on natural carbohydrates degradation, and to mine gene resources for biomass conversion.

Methods and results: We sequenced the whole genome of a novel carbohydrate-degrading Flavobacterium sp. strain YJ01. The genome size of strain YJ01 was 5.48 Mb and encoded 4674 predicted genes. Comparative genomic analysis revealed Flavobacterium strains were characterized by the presence of abundant genes associated with catalytic activity and metabolic processes, especially carbohydrate metabolism. About 9% of genes of strain YJ01 encoded carbohydrate-active enzymes. These enzymes can act on various complex natural and cellular carbohydrates. The synergistic effect of the enzymes on the hydrolysis of complex natural polysaccharides was further experimentally evidenced by using starch and xylan as substrates, in which the degradation rate of an enzyme combination was ~10-fold higher than that of the single enzyme.

Conclusions: Flavobacterium sp. strain YJ01 has a high degree of catalytic and metabolic activity toward carbohydrates, and it harbors abundant, complete, and efficient enzymes for mediating complex polysaccharide degradation. These enzymes, acting synergistically on complex substrates, greatly improved the efficiency of digestion, which may be associated with the extensive ecological adaptability of Flavobacterium, which genetically heterologous divergent from extremely environments origin Flavobacterium strains.