海洋細菌由来のPL6アルギン酸リアーゼAly94のクローニングと特性評価

Microbial alginate lyases are essential biocatalysts for analyzing alginate structure and sustainably producing bioactive alginate oligosaccharides (AOS). In this study, we characterized Aly94, a novel alginate lyase from the polysaccharide lyase family 6 (PL6) family, identified from a marine sediment metagenomic library. Biochemical analyses showed Aly94 exhibits optimal activity at 40 ℃ in 50 mM NaH₂PO₄-Na₂HPO₄ buffer (pH 7.0). Adding 20 mM NaCl significantly increases its catalytic efficiency. The enzyme exhibits a strong preference for polyguluronate (polyG) over polymannuronate (polyM), with specific activities of 4.19 U/mg (polyG), 0.25 U/mg (polyM), and 2.45 U/mg (alginate). When degrading substrates-particularly polyG-Aly94 primarily generates trisaccharides. Although Aly94 acts as an endolytic alginate lyase, it also could digest the monosaccharides from small oligosaccharide chains (∆G3, ∆G4). These catalytic properties, combined with its polyG-specific depolymerization, made Aly94 a promising candidate for biotechnological applications requiring controlled alginate saccharification and high-value AOS production.