Alginate is a major component of brown algae cell walls and can be degraded via β-elimination by alginate lyases. These enzymes are classified into polysaccharide lyases and oligo-alginate lyases (Oals), with Oals mainly represented by the PL15 and PL17 families. Unlike PL17 Oals, which are widely present in alginate-degrading microorganisms, PL15 enzymes are only identified in a limited number of microorganisms, and their biochemical characteristics remain poorly understood. In this research, a novel PL15 alginate lyase, VBAly15A, from the marine bacterium,