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


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)-beta-D-glucan. This structure was determined by methylation analysis and conventional (1)H- and (13)C-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 beta-glucan, as the predominant EPS, and it is also able to produce two heteropolysaccharides.


CONCLUSIONS
This work provides a better understanding of EPS synthesis by O. oeni and shows the first EPS structure described for this species.
Ibarburu
I
I
Departamento de Química Aplicada, Facultad de Ciencias Químicas, Universidad del País Vasco, San Sebastián, Spain.
Soria-Díaz
M E
ME
Rodríguez-Carvajal
M A
MA
Velasco
S E
SE
Tejero-Mateo
P
P
Gil-Serrano
A M
AM
Irastorza
A
A
Dueñas
M T
MT
D000596:Amino Acids / Q000378:metabolism; D002244:Carbon / Q000378:metabolism; D003470:Culture Media; D000431:Ethanol / Q000378:metabolism; D005285:Fermentation; D005947:Glucose / Q000378:metabolism; D007934:Leuconostoc / Q000254:growth & development* / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D009584:Nitrogen / Q000378:metabolism; D011135:Polysaccharides, Bacterial / Q000096:biosynthesis* / Q000737:chemistry; D015003:Yeasts / Q000378:metabolism; D047071:beta-Glucans / Q000378:metabolism
D000596:Amino Acids; D003470:Culture Media; D011135:Polysaccharides, Bacterial; D047071:beta-Glucans; C017721:casamino acids; D000431:Ethanol; D002244:Carbon; D005947:Glucose; D009584:Nitrogen