title: Screening of enzymatic activities for the depolymerisation of the marine bacterial exopolysaccharide HE800.
abstract: The exopolysaccharide (EPS) HE800 is a marine-derived polysaccharide (from 8 × 10(5) to 1.5 × 10(6) g mol(-1)) produced by Vibrio diabolicus and displaying original structural features close to those of glycosaminoglycans. In order to confer new biological activities to the EPS HE800 or to improve them, structural modifications need to be performed. In particular, depolymerisation is required to generate low-molecular-weight derivatives. To circumvent the use of chemical methods that lack specificity and reproducibility, enzymes able to perform such reaction are sought. This study reports the screening for enzymes capable of depolymerising the EPS HE800. A large diversity of enzyme sources has been studied: commercially available glycoside hydrolases with broad substrate specificity, lyases, and proteases as well as growing microorganisms. Interestingly, we found that the genus Enterococcus and, more particularly, the strain Enterococcus faecalis were able to depolymerise the EPS HE800. Partial characterization of the enzymatic activity gives evidence for a random and incomplete depolymerisation pattern that yields low-molecular-weight products of 40,000 g mol(-1). Genomic analysis and activity assays allowed the identification of a relevant open reading frame (ORF) which encodes an endo-N-acetyl-galactosaminidase. This study establishes the foundation for the development of an enzymatic depolymerisation process.
authors.affiliation: Ifremer, Laboratoire de Biotechnologie et Molécules Marines, rue de l'Ile d'Yeu, BP 21105, 44311 Nantes Cedex 3, France.
authors.forename: Coraline
authors.initials: C
authors.lastname: Rigouin
authors.forename: Christine
authors.initials: C
authors.lastname: Delbarre-Ladrat
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Ratiskol
authors.forename: Corinne
authors.initials: C
authors.lastname: Sinquin
authors.forename: Sylvia
authors.initials: S
authors.lastname: Colliec-Jouault
authors.forename: Michel
authors.initials: M
authors.lastname: Dion
mesh_terms: D013293:Enterococcus faecalis / Q000201:enzymology*; D006596:Hexosaminidases / Q000302:isolation & purification* / Q000378:metabolism*; D006868:Hydrolysis; D008403:Mass Screening / Q000379:methods*; D008970:Molecular Weight; D009844:Oligosaccharides / Q000737:chemistry / Q000378:metabolism; D011135:Polysaccharides, Bacterial / Q000737:chemistry / Q000378:metabolism*; D014733:Vibrio / Q000378:metabolism*
chemical_list: D009844:Oligosaccharides; D011135:Polysaccharides, Bacterial; D006596:Hexosaminidases