Expression and characterization of three alginate lyases from Vibrio sp. E: targeting kelp hydrolysis and biofilm disruption.

A marine bacterial strain, Vibrio sp. E, capable of producing alginate lyases, was isolated from seawater. Three alginate lyase genes from this strain were cloned and expressed in Escherichia coli. The recombinant enzymes, designated AlyE1, AlyE2, and AlyE3, exhibited optimal activity at pH 9.0 and high pH stability, retaining over 80% of their initial activity across a pH range of 6.0 to 10.0. They retained more than 50% activity at 4 °C and over 30% at 100 °C. AlyE1 and AlyE3 demonstrated thermo-tolerance, recovering the majority of of their initial activity after heat treatment (>80 °C, <120 min) and cooling (>80 °C, >10 min). All three enzymes exhibited strong NaCl tolerance but were not NaCl-dependent. They were characterized as bifunctional and endolytic lyases, which was effective in kelp (Laminaria japonica) hydrolysis and in disrupting Pseudomonas aeruginosa biofilms.