Original Research ARTICLE
Wort substrate consumption and metabolite production during lambic beer fermentation and maturation explain the successive growth of specific bacterial and yeast species
- 1Vrije Universiteit Brussel, Belgium
- 2Ghent University, Belgium
The present study combined high-throughput culture-dependent plating and culture-independent amplicon sequencing with a metabolite target analysis to systematically dissect the identity, evolution, and role of the microorganisms, substrates, and metabolites during the four-phase fermentation and maturation process of lambic beer production. This led to the following new insights. The changing physicochemical parameters and substrate and metabolite compositions of the fermenting wort and maturing lambic beer provoked several transitions between microbial species and explained the four-step production process. Manual wort acidification with lactic acid shortened the enterobacterial phase and thus kept biogenic amine formation by enterobacteria present during the early stages of fermentation at a minimum. Growth advantages during the alcoholic fermentation phase caused a transition from the prevalence by Hanseniaspora uvarum and Kazachstania species to that by Saccharomyces cerevisiae and later on Saccharomyces kudriavzevii, due to changing environmental parameters. During the acidification phase, Pediococcus damnosus was prevalent and performed a malolactic fermentation. Acetobacter pasteurianus produced acetic acid and acetoin. Upon maturation, Dekkera species appeared, together with P. damnosus and Pichia membranifaciens, thereby contributing to acetic acid production, depending on the oxygen availability. Moreover, the Dekkera species consumed the acetoin produced by the acetic acid bacteria for redox balancing. The breakdown of maltooligosaccharides seemed to be independent of the occurrence of Dekkera species and started already early in the fermentation process.
Keywords: Lambic beer, Dekkera, malolactic fermentation, MALDI-TOF MS, Amplicon sequencing
Received: 10 Sep 2018;
Accepted: 29 Oct 2018.
Edited by:Fabio Minervini, Università degli Studi di Bari, Italy
Reviewed by:Maurizio Ciani, Università Politecnica delle Marche, Italy
Pasquale Russo, University of Foggia, Italy
Thibault Nidelet, Institut National de la Recherche Agronomique Centre Montpellier, France
Copyright: © 2018 De Roos, Vandamme and De Vuyst. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Prof. Luc De Vuyst, Vrije Universiteit Brussel, Brussels, 1050, Belgium, email@example.com