New article - a review - on the microbial interactions in alcoholic beverages

Microbial interactions in alcoholic beverages (Review)

Rafael Torres-Guardado, Braulio Esteve-Zarzoso, Cristina Reguant, Albert Bordons

International Microbiology  2021  https://doi.org/10.1007/s10123-021-00200-1

    This article is a review that examines the different types of interactions between the microorganisms involved in the fermentation processes of alcoholic beverages produced all over the world from cereals or fruit juices. 

    The alcoholic fermentation converting sugars into ethanol is usually carried out by yeasts, mainly Saccharomyces cerevisiae, which can grow directly using fruit sugars (wine, cider, and others), or on previously hydrolyzed starch of cereals (beers and others). Some of these beverages, or the worts from cereals, can be distilled to obtain spirits. Besides S. cerevisiae, all alcoholic beverages can contain other microorganisms, mostly lactic acid bacteria and other yeasts —the non-Saccharomyces yeasts—. 

    The interactions between all these microorganisms are very diverse and complex, as in any natural occurring ecosystem. The positive or negative effects of these interactions on the organoleptic qualities of the final product have been also revised. Focusing mainly on the alcoholic beverages produced by spontaneous fermentations, this paper reviews the interactions between the different yeasts and lactic acid bacteria in wine, cider, beer and in spirits such as tequila, mezcal and cachaça.

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Online BE (Wine Biotechnology) Group meeting, 9th July 2021

 Last Friday 9th July we have celebrated the monthly online meeting of Wine Biotechnology Research Group.

The last results of different projects have been discussed and our colleague Sandra Martín (predoctoral researcher) has presented her work carried out on design of microbial consortia for improving stability and bioactivity of wines.

Two new articles on the effect of non-Saccharomyces on Oenococcus oeni

1) Torulaspora delbrueckii promotes malolactic fermentation in high polyphenolic red wines

Aitor Balmaseda, Nicolas Rozès, Albert Bordons, Cristina Reguant *

LWT Food Sci Technol 2021, 148, 111777: https://doi.org/10.1016/j.lwt.2021.111777

The interactions of Torulaspora delbrueckii and O. oeni in wines from grapes with different degrees of maturity were studied. The results showed higher total polyphenolic index (TPI) values in T. delbrueckii wines. Overall, the use of T. delbrueckii resulted in better MLF performances.

 

2) Simulated lees of different yeast species modify the performance of malolactic fermentation by Oenococcus oeni in wine-like medium

Aitor Balmaseda, Nicolas Rozès, Albert Bordons, Cristina Reguant *

Food Microbiology 2021, 99, 103839: https://doi.org/10.1016/j.fm.2021.103839

This is the first study of MLF with different O. oeni strains in the presence of S. cerevisiae and non-Saccharomyces yeast lees. Non-Saccharomyces lees, especially from some strains of Torulaspora delbrueckii, showed higher compatibility with some O. oeni strains, with a shorter MLF and a maintained bacterial cell viability. 

 

Online BE (Wine Biotechnology) Group meeting, 4th June 2021

Last Friday 4th June we have celebrated the monthly online meeting of Wine Biotechnology Research Group.

The last results of different projects have been discussed and our colleague Candela Ruiz de Villa Sardón (predoctoral researcher) has presented her work carried out on screening of alcoholic and malolactic fermentations with non-Saccharomyces and Oenococcus oeni, in synthetic wine and in wine rosé.

Online BE (Wine Biotechnology) Group meeting, 7th May 2021

Last Friday 7th May we have celebrated an online meeting of Wine Biotechnology Research Group.

The last results of different projects have been discussed and our colleague Aitor Balmaseda (predoctoral researcher) has presented the work carried out during his research stage at the University of Burgundy in Dijon, on the effects of Torulaspora delbrueckii on nitrogen metabolism of Oenococcus oeni.

New article on ethanol reduction by multistarter yeast inoculum

Effect of a multistarter yeast inoculum on ethanol reduction and population dynamics in wine fermentation

Xiaolin Zhu, Maria-Jesús Torija, Albert Mas, Gemma Beltran*, Yurena Navarro

Foods 2021, 10, 623. https://doi.org/10.3390/foods10030623

Microbiological strategies are currently being considered as methods for reducing the ethanol content of wine. In this study, fermentations started with a multistarter of three non-Saccharomyces yeasts (Metschnikowia pulcherrima (Mp), Torulaspora delbrueckii (Td) and Zygosaccharomyces bailii (Zb)) at different inoculum concentrations, and S. cerevisiae (Sc) was inoculated into fermentations at 0 h (coinoculation), 48 h or 72 h (sequential fermentations).

The analysis of the microbial populations showed Td as the dominant non-Saccharomyces yeast in all fermentations, and Mp the minority yeast. Sc was able to grow in all fermentations where it was involved, being the dominant yeast at the end of fermentation. 

We obtained a significant ethanol reduction of 0.48 to 0.77 % (v/v) in sequential fermentations, with increased concentrations of lactic and acetic acids. The highest reduction was achieved when the inoculum concentration of non-Saccharomyces was ten times higher (10⁷ cells/mL) than that of S. cerevisiae.