The enzymatic ulvan depolymerisation system from the alga-associated marine flavobacterium Formosa agariphila

A marine bacterial enzymatic cascade degrades the algal polysaccharide ulvan

“…Ulvan-specific degradation-related gene loci ('polysaccharide utilization loci', PULs) such as PUL H from Formosa agariphila encode PL28 and GH105 together with over 10 additional, putative enzymes, which were predicted to be involved in ulvan utilization. While PL28 and GH105 degrade ulvan, the other enzymes that were produced in Escherichia coli did not show activity 15 . This result suggested that a complex cascade of sequential enzymatic reactions is required for complete ulvan degradation 15,17 .…”

“…While PL28 and GH105 degrade ulvan, the other enzymes that were produced in Escherichia coli did not show activity 15 . This result suggested that a complex cascade of sequential enzymatic reactions is required for complete ulvan degradation 15,17 .…”

“…Furthermore, Rha3S can be modified by β-1,2-linked GlcA side chains and the GlcA-Rha3S or IdoA-Rha3S pattern can be interrupted by consecutive GlcA residues [7][8][9] . Increased interest in the enzymatic degradation of ulvan recently led to the description of several ulvan-active enzymes [10][11][12][13][14][15] . So far, and to the best of our knowledge, only two types of enzymes from different carbohydrate-active enzyme (CAZyme) families showed activity on ulvan.…”

“…Ulvan polysaccharide lyases of the families PL24, PL25 and PL28 catalyze the initial cleavage between Rha3S and GlcA or IdoA, resulting in the formation of unsaturated uronic acid residues at the end of the formed oligosaccharide. Unsaturated uronic acid residues are removed by glycoside hydrolases (GHs) from the family GH105 15,16 . Ulvan-specific degradation-related gene loci ('polysaccharide utilization loci', PULs) such as PUL H from Formosa agariphila encode PL28 and GH105 together with over 10 additional, putative enzymes, which were predicted to be involved in ulvan utilization.…”

“…Here, we experimentally established the complex ulvan degradation pathway of F. agariphila KMM 3901 T , a marine flavobacterium, which was isolated from a green alga in the Sea of Japan 18 . These degradation-related enzymes are encoded in an ulvan-specific PUL in the bacterial genome 15 .…”