Overexpression and biochemical characterization of a truncated endo-α (1 → 3)-fucoidanase from alteromonas sp. SN-1009

•A truncated endo-α(1 → 3)-fucoidanase was expressed and characterized in detail.•Catalytic residues of endo-α(1 → 3)-fucoidanase were identified and confirmed.•Degraded products of fucoidan by α(1 → 3)-fucoidanase were characterized by ESI-MS2.•Kjellmaniella crassifolia fucoidan is complex and composed of α(1 → 3) linked l-fucose.