Cellulosimicrobium cellulans strain E4-5 enzymatic hydrolysis of curdlan for production of (1 → 3)-linked β-d-glucan oligosaccharides

In order to find an efficient enzymatic tool for curdlan degradation to produce (1 → 3)-linked β-d-glucan oligosaccharides, strain E4-5 (registration number JN089883, Genbank) was isolated from seaside soil. The 16S rRNA gene sequencing classified it as Cellulosimicrobium cellulans. It was the first reported microorganism that succeeded in degrading high-set heated curdlan blocks. The ferments of strain E4-5 also showed good degradation effects on laminaran and alkali-neutralized curdlan. Due to the products with less amount of glucose, it was assumed that endo-1,3-β-glucanases of strain E4-5 had a greater hydrolyzing effect than exo-1,3-β-glucanases. This indicated that strain E4-5 was a promising microorganism to hydrolyze (1 → 3)-linked β-d-glucan. Moreover, alkali-neutralization pretreatment was effective for promoting a more diversified degree of polymerization (DP) of (1 → 3)-linked β-d-glucan oligosaccharides under enzymatic hydrolysis and will pave the way for making full use of curdlan for production of glucan oligosaccharides.