HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Maicas, S. Articles by Pardo, I. Search for Related Content PubMed PubMed Citation Articles by Maicas, S. Articles by Pardo, I. Agricola Articles by Maicas, S. Articles by Pardo, I.

NAD(P)H regeneration is the key for heterolactic fermentation of hexoses in Oenococcus oeni

Departament de Microbiologia i Ecologia, Facultat de Biologia, Universitat de València, C/Dr Moliner, 50, Burjassot, València, Spain 46100-E¹

Author for correspondence: Isabel Pardo. Tel: +34 6 3864390. Fax: +34 6 3864372. e-mail: Isabel.Pardo{at}uv.es

Oenococcus oeni (formerly Leuconostoc oenos) can perform malolactic fermentation, converting L-malate to L-lactate and carbon dioxide, in wines. The energy and redox potential required to support the growth of the micro-organism are supplied mainly by the consumption of carbohydrates via the heterolactic pathway. In the first steps of hexose metabolism two molecules of NAD(P)⁺ are consumed, which must be regenerated in later reactions. The aim of this work was to test if aerobic growth of O. oeni promotes higher cell yields than anaerobic conditions, as has been shown for other lactic acid bacteria. O. oeni M42 was found to grow poorly under aerobic conditions with glucose as the only carbohydrate in the medium. It was demonstrated that O₂ inactivates the enzymes of the ethanol-forming pathway, one of the two pathways which reoxidizes NAD(P)⁺ cofactors in the heterolactic catabolism of glucose. These results suggest that the regeneration of cofactors is the limiting factor for the aerobic consumption of glucose. When external electron acceptors, such as fructose or pyruvate, were added to glucose-containing culture medium the growth of O. oeni was stimulated slightly; fructose was converted to mannitol, oxidizing two molecules of NAD(P)H, and pyruvate was transformed to lactate, enabling the regeneration of NAD⁺. The addition of cysteine seemed to suppress the inactivation of the ethanol-forming pathway enzymes by O₂, enabling glucose consumption in aerobic conditions to reach similar rates to those found in anaerobic conditions.

Keywords: aerobic glucose catabolism, NADH, ethanol-forming pathway, Leuconostoc oenos

Abbreviations: ADH, alcohol dehydrogenase; EFP, ethanol-forming pathway; LAB, lactic acid bacteria; MBB, MLO basal broth; MBBG, MLO basal broth plus glucose (55mM); X_max, maximum biomass

^a Present address: Facultad de Ciencias Experimentales y de la Salud, Universidad Cardenal Herrera–CEU, Edifici Seminari S/U, 46113, Montcada, Spain.

This article has been cited by other articles:

				E. Arskold, E. Lohmeier-Vogel, R. Cao, S. Roos, P. Radstrom, and E. W. J. van Niel Phosphoketolase Pathway Dominates in Lactobacillus reuteri ATCC 55730 Containing Dual Pathways for Glycolysis J. Bacteriol., January 1, 2008; 190(1): 206 - 212. [Abstract] [Full Text] [PDF]

				D. Jussier, A. Dube Morneau, and R. Mira de Orduna Effect of Simultaneous Inoculation with Yeast and Bacteria on Fermentation Kinetics and Key Wine Parameters of Cool-Climate Chardonnay Appl. Envir. Microbiol., January 1, 2006; 72(1): 221 - 227. [Abstract] [Full Text] [PDF]

				N. Wagner, Q. H. Tran, H. Richter, P. M. Selzer, and G. Unden Pyruvate Fermentation by Oenococcus oeni and Leuconostoc mesenteroides and Role of Pyruvate Dehydrogenase in Anaerobic Fermentation Appl. Envir. Microbiol., September 1, 2005; 71(9): 4966 - 4971. [Abstract] [Full Text] [PDF]