Abstract
Ulvan is a complex sulfated polysaccharide in the cell walls of green algae with extensive applications in food, pharmaceutical, and agricultural industries, prompting extensive studies on ulvan, its oligosaccharides, monosaccharides, and cost-effective depolymerization methods. Our primary objectives were to investigate novel ulvan-utilizing marine bacteria, perform recombinant engineering of genes responsible for ulvan depolymerization, and determine their potential industrial applications. Samples were collected from Jeju Island, which is a South Korean region with significant excessive green algal growth, especially that of Ulva species. The marine bacterium Pseudoalteromonas agarivorans efficiently uses ulvan as its primary carbon source, indicating its potential for ulvan degradation. Through whole-genome sequencing the paul40 gene, which is a polysaccharide lyase family 40 (PL40) member, was identified and subsequently engineered into the pET-16b vector for expression as a His-tagged 95 kDa fusion protein. The ulvan depolymerization process was evaluated and confirmed using various analytical techniques including dinitrosalicylic acid assay, thin-layer chromatography, and gel permeation chromatography. Optimal enzyme activity occurred at 35°C, pH 8.0 in phosphate buffer, and 2.5 mM of NaCl. Furthermore, enzyme characterization and specific activity measurements were performed. This study is the first to report hyaluronidase and elastase inhibition by ulvan and its derivatives along with the characterization of an ulvan lyase enzyme from the PL40 family. ONE-SENTENCE SUMMARY: This study reports the identification and recombinant expression of a novel ulvan-degrading enzyme from Pseudoalteromonas agarivorans, demonstrating its potential for cosmetic industrial applications by revealing ulvan's and partially hydrolyzed ulvan's hyaluronidase and elastase inhibition properties.