Purification of the exopolysaccharide produced by Alteromonas infernus: identification of endotoxins and effective process to remove them
|Author(s)||Grivaud-Le Du Alicia1, Zykwinska Agata1, Sinquin Corinne1, Ratiskol Jacqueline1, Weiss Pierre2, Vinatier Claire2, Guicheux Jerome2, Delbarre-Ladrat Christine1, Colliec-Jouault Sylvia1|
|Affiliation(s)||1 : IFREMER, Lab Ecosyst Microbiens & Mol Marines Biotechnol, EM3B, Rue Ile dYeu, F-44311 Nantes 3, France.
2 : Univ Nantes, Inserm UMRS 1229, UFR Odontol, 1 Pl Alexis Ricordeau, F-44042 Nantes 1, France.
|Source||Applied Microbiology And Biotechnology (0175-7598) (Springer), 2017-09 , Vol. 101 , N. 17 , P. 6597-6606|
|WOS© Times Cited||2|
|Keyword(s)||Marine Alteromonas infernus, Bacterial exopolysaccharide, Endotoxin, Characterization, Purification, Fermentation, Process|
Alteromonas infernus bacterium isolated from deep-sea hydrothermal vents can produce by fermentation a high molecular weight exopolysaccharide (EPS) called GY785. This EPS described as a new source of glycosaminoglycan-like molecule presents a great potential for pharmaceutical and biotechnological applications. However, this unusual EPS is secreted by a Gram-negative bacterium and can be therefore contaminated by endotoxins, in particular the lipopolysaccharides (LPS). Biochemical and chemical analyses of the LPS extracted from A. infernus membranes have shown the lack of the typical LPS architecture since 3-deoxy-d-manno-oct-2-ulopyranosonic acid (Kdo), glucosamine (GlcN), and phosphorylated monosaccharides were not present. Unlike for other Gram-negative bacteria, the results revealed that the outer membrane of A. infernus bacterium is most likely composed of peculiar glycolipids. Furthermore, the presence of these glycolipids was also detected in the EPS batches produced by fermentation. Different purification and chemical detoxification methods were evaluated to efficiently purify the EPS. Only the method based on a differential solubility of EPS and glycolipids in deoxycholate detergent showed the highest decrease in the endotoxin content. In contrast to the other tested methods, this new protocol can provide an effective method for obtaining endotoxin-free EPS without any important modification of its molecular weight, monosaccharide composition, and sulfate content.