Production, characterization and application of an alginate lyase, AMOR_PL7A, from hot vents in the Arctic Mid-Ocean Ridge.

Enzymatic depolymerization of seaweed polysaccharides is gaining interest for the production of functional oligosaccharides and fermentable sugars. We describe a thermostable alginate lyase belonging to Polysaccharide Lyase family 7 (PL7), which can be used to degrade brown seaweed, Saccharina latissima, at conditions also suitable for a commercial cellulase cocktail (Cellic CTec2). This enzyme, AMOR_PL7A, is a beta-D-mannuronate specific (EC 4.2.2.3) endoacting alginate lyase, which degrades alginate and poly mannuronate within a broad range of pH, temperature and salinity. At 65 degrees C and pH 6.0, its Km and k(cat) values for sodium alginate are 0.51 +/- 0.09 mg/mL and 7.8 +/- 0.3 s(-1) respectively. Degradation of seaweed with blends of Cellic CTec2 and AMOR_PL7A at 55 degrees C in seawater showed that the lyase efficiently reduces viscosity and increases glucose solublization. Thus, AMOR_PL7A may be useful in development of efficient protocols for enzymatic seaweed processing.