Growth and exopolysaccharide (EPS) production by Oenococcus oeni I4 and structural characterization of their EPSs

Abstract

Aims: To study the influence of medium constituents on growth, and exopolysaccharide (EPS) production by a strain of Oenococcus oeni. The structure of one of the EPSs has also been characterized. Methods and Results: EPS concentration was estimated by the phenol/sulfuric acid method. After purification and fractionation of crude EPSs, the sugar composition was determined by GLC‐MS of the TMS methyl glycosides. The major polysaccharide is 2‐substituted‐(1–3)‐β‐d‐glucan. This structure was determined by methylation analysis and conventional 1H‐ and 13C‐nuclear magnetic resonance spectroscopy. In addition, O. oeni synthesized two heteropolysaccharides, although a lesser proportion, constituted by galactose and glucose, and one of them also showed rhamnose. The sugar source has a clear influence on growth and EPS synthesis, and EPS production was not enhanced by adding ethanol or increasing the nitrogen source. EPS biosynthesis starts in the exponential growth phase, and continued during the stationary growth phase. Conclusions: Higher EPS yields were obtained on cultures grown on glucose + fructose. O. oeni produces a β‐glucan, as the predominant EPS, and it is also able to produce two heteropolysaccharides. Significance and Impact of the Study: This work provides a better understanding of EPS synthesis by O. oeni and shows the first EPS structure described for this species.

Characterization ofgtf, a Glucosyltransferase Gene in the Genomes ofPediococcus parvulusandOenococcus oeni, Two Bacterial Species Commonly Found in Wine

“…The presence of gtf in the genome of this useful species is worrying, as it suggests that it can represent a vector for ropiness in wine. Although the species has never been blamed, the role of O. oeni in cider ropiness can be suggested from the results of Ibarburu et al (26) showing that O. oeni I4 produces ␤-glucan in a model medium and induces an increase in viscosity. Closer characterization of the gtf gene in the wine O. oeni strains harboring it is now necessary to (i) specify the O. oeni gtf gene sequence and location and (ii) assess the gene expression and the protein functionality but also to (iii) analyze the possible role of gtf in bacterial strain persistence in wine.…”

Application of cross‐flow ultrafiltration for isolating exopolymeric substances from a marine diatom (Amphora sp.)

“…However, current isolation and analysis methods have difficulties with harvesting and purifying sufficient quantities of EPS from phytoplankton cultures. Ethanol precipitation, the method most often used for EPS isolation (Schepetkin et al 2005;Wang and Xia 2005;Kim et al 2006;Lbarburu et al 2007), is ineffective for many cultures due to the large quantities of ethanol required for large-scale isolation of EPS from aqueous media such as seawater. Currently, membrane technology is the preferred method to desalt and concentrate macromolecules from complex matrices.…”

Characterization of Exopolysaccharides Produced by Rhizobia Species

“…Further, environmental factors such as concentration of the energy source, nitrogen, phosphate starvation, the C/N ratio, and a diverse range of stress conditions (e.g., desiccation, temperature, and ionic strength) affect EPS production. These factors also influence the structure and rheological properties of EPS (Ibarburu et al, 2007;Staudt et al, 2012).…”