terclim by ICS banner
IVES 9 IVES Conference Series 9 CHANGES IN METABOLIC FLUXES UNDER LOW PH GROWTH CONDITIONS: CAN THE SLOWDOWN OF CITRATE CONSUMPTION IMPROVE OENOCOCCUS OENI ACID-TOLERANCE?

CHANGES IN METABOLIC FLUXES UNDER LOW PH GROWTH CONDITIONS: CAN THE SLOWDOWN OF CITRATE CONSUMPTION IMPROVE OENOCOCCUS OENI ACID-TOLERANCE?

Abstract

Oenococcus oeni is the main Lactic Acid Bacteria responsible for malolactic fermentation, converting malic acid into lactic acid and carbon dioxide in wines. Following the alcoholic fermentation, this second fermentation ensures a deacidification and remains essential for the release of aromatic notes and the improvement of microbial stability in many wines. Nevertheless, wine is a harsh environment for microbial growth, especially because of its low pH (between 2.9 and 3.6 depending on the type of wine) and nutrient deficiency. In order to maintain homeostasis and ensure viability, O. oeni possesses different cellular mechanisms including organic acid metabolisms which represent also the major pathway to synthetize energy in wine. Indeed, uptake and consumption of malate and citrate by this bacteria enables to activate a proton motive force (PMF) hence maintaining an intracellular pH by proton consumption1,2.

Citrate is found in wine at small concentrations (0.13 to 0.90 g/L). It can be metabolized by O. oeni into acetate, pyruvate and then aromatic compounds such as diacetyl, acetoin and 2,3-butanediol. The ability of citrate metabolism to activate the PMF could play a central role in the acid-tolerance of this bacterium. Nevertheless, a previous study has described an inhibition of O. oeni growth at low pH in presence of high amounts of citrate3. This toxic effect could come from the synthesis of one of the citrate metabolites as acetate.

In order to understand how citrate metabolism can be linked to acid tolerance of this bacterium, consumption of citrate was investigated in a great diversity of O. oeni strains. In addition, malate and sugar consumptions were also followed, as they can be impacted by citrate metabolism. These experiments enabled to draw metabolic fluxes in O. oeni according to the pH of the medium. In most cases, ma- late is first metabolized, then citrate and sugars, sequentially, proving that the priority is given to organic acid consumption at the expense of sugars in this bacterium. However, this experiment revealed different citrate consumption profiles which may be correlated to a greater or lesser acid tolerance according to the strain. Furthermore, a genomic comparison demonstrated the presence of mutations in the citrate operon of acid-tolerant industrial strains. Hence, acid tolerance could be linked to a change in the rate of citrate consumption in O. oeni.

 

1. Ramos, A., Poolman, B., Santos, H., Lolkema, J.S., Konings, W.N., 1994. Uniport of anionic citrate and proton consumption in ci-trate metabolism generates a proton motive force in Leuconostoc oenos. J. Bacteriol. 176, 4899–4905. https://doi.org/10.1128/jb.176.16.4899-4905.1994
2. Salema, M., Lolkema, J.S., Romão, M.V.S., Dias, M.C.L., 1996. The proton motive force generated in Leuconostoc oenos by L-malate fermentation. J. Bacteriol. 178, 3127–3132. https://doi.org/10.1128/jb.178.11.3127-3132.1996
3. Augagneur, Y., Ritt, J.-F., Linares, D.M., Remize, F., Tourdot-Maréchal, R., Garmyn, D., Guzzo, J., 2007. Dual effect of organic acids as a function of external pH in Oenococcus oeni. Arch. Microbiol. 188, 147–157. https://doi.org/10.1007/s00203-007-0230-0

DOI:

Publication date: February 9, 2024

Issue: OENO Macrowine 2023

Type: Article

Authors

Camille Eicher1, Joana Coulon2, Marion Favier2, Edouard Munier1, Thierry Tran1, Hervé Alexandre1, Cristina Reguant Miran-da3, Cosette Grandvalet1

1. UMR A. 02.102 Procédés Alimentaires et Microbiologiques, L’institut Agro Dijon, Université de Bourgogne Franche-Comté, Dijon, France
2. BioLaffort, Floirac, France
3. Departament de Bioquímica i Biotecnologia, Facultat d’Enologia, Universitat Rovira i Virgili, Tarragona, Spain

Contact the author*

Keywords

Oenococcus oeni, Citrate, Metabolic fluxes, Acid-tolerance

Tags

IVES Conference Series | oeno macrowine 2023 | oeno-macrowine

Citation

Related articles…

DETERMINATION OF MINERAL COMPOSITION IN CV. TERAN (VITIS VINIFERA L.) RED WINE AFFECTED BY PRE-FERMENTATIVE MASH COOLING, HEATING, SAIGNÉE TECHNIQUE AND PROLONGED POST-FERMENTATIVE MACERATIONS

This study aimed to determine mineral composition in red wine obtained from cv. Teran (Vitis vinifera L.), autochtonous Croatian grape variety. Six different vinification treatments, including the control treatment (7-day standard maceration), were performed to study the effects of: 48-hour pre-fermentative mash cooling (8 °C) followed by prolonged post-fermentative maceration of 13 days (C15), 28 days (C30), and saignée technique (juice runoff) proceeded with prolonged post-fermentative maceration of 13 days (CS15); and effect of 48-hour heating (50 °C) followed by prolonged post-fermentative maceration of 13 days (H15) and 28 days (H30) on macro- and microelements in wine.

Read More

CHARACTERISTIC EXTRACTION OF THE PHENOL COMPOUNDS IN KOSHU (VITIS VINIFERA CV.) WINE DURING THE MACERATION

Koshu is one of the indigenous grape variety that has been grown in Japan for more than one thousand years. Recent research showed that it has 70% of Vitis vinifera genes. In 2010, the Koshu variety was included in ‘International List of Vine and Varieties and their Synonyms’ managed by the ‘International Organisation of Vine and Wine’ and has further fueled its popularity in Japan. It is the most cultivated variety for winemaking in Japan.
Koshu berries have light purple skins. The variety is mainly used to produce white wines such as an aromatic wine and a wine produced by sur lie method although various styles are produced.

Read More

INFLUENCE OF WINEMAKING VARIABLES AND VINEYARD LOCATIONS ON CHEMICAL AND SENSORY PROFILES OF SOUTH TYROLEAN PINOT BLANC

Pinot Blanc, an important grape variety grown in some mountain areas of Northern Italy such as South Tyrol over the last decades, with its cultivation covering 10.3% of the total vineyards, has compatible climatic conditions (e.g. heat requirements) which are normally found in the geographical areas of the mountain viticulture [1,2,3,4]. Climatic changes are hastening the growth of this variety at higher elevations, particularly for the production of high quality wine.

Read More

AGEING BOTTLED WINES SUBMERGED IN SEA: DOES IT IMPACT WINE COMPOSITION?

Aging wines is a common practice in oenology, which in recent years has undergone some innovations. Currently, we are witnessing the practice of aging bottled wine in depth, immersed in the sea or in reservoirs, for variable periods of time, but so far, little is known about the impact of aging in depth on the physicochemical properties, of wines.
The objective of this work was to evaluate the impact of this practice on the physicochemical characteristics, in particular to verify changes in the volatile composition of wines bottled and subsequently immersed in depth. A red wine from Cabernet Sauvignon was bottled and a set of bottles were submerged from July to February (2020), another set of bottles were submerged from February to September (2020) and another set was kept in the wine cellar. Bottles from each set were analyzed (in triplicate) in July 2021.

Read More

Metabolomics for grape and wine research: exploring the contributions of amino acids to wine flavour

A critical aspect of wine quality is the overall expression of wine flavour, which is formed by the interplay of volatile aroma compounds, their precursors, and taste and matrix components.
Grapes directly contribute to wine only a small number of potent aroma compounds, and the unique
sensory attributes and perceived quality of a wine result from combining 100s of metabolites of grapes, yeast and bacteria, and oak wood.

Read More