Abstract:Alginate lyases could effectively degrade alginates into alginate oligosaccharides (AOS). AOS have good physical characteristics and excellent physiological functions, and are widely applied in the fields of food, cosmetics, and pharmaceuticals. To efficiently prepare AOS, a novel alginate lyase belonging to the PL-7 family and derived from Reinekea thalattae was screened and identified, designated as Reth-aly. The encoding gene of Reth-aly was cloned and overexpressed in Escherichia coli BL21. Under conditions of pH 7.5 (Tris-HCl buffer), 35 ℃ and 600 mmol/L NaCl, Reth-aly demonstrated its highest catalytic activity. With sodium alginate as the substrate, its catalytic activity reached 765.7 U/mg. Degradation products included AOS with a degree of polymerization (DP) of 2~4. Compared with other PL-7 family alginate lyases, it showed good stability with a half-life of 5.4 h at 35 ℃. Reth-aly showed robust catalytic activity in high-salt environments, indicating promising application prospects in AOS bioproduction.
