Unraveling the Role of Acetic Acid Bacteria Comparing Two Acetification Profiles From Natural Raw Materials: A Quantitative Approach in Komagataeibacter europaeus

Abstract

The industrial production of vinegar is carried out by the activity of a complex microbiota of acetic acid bacteria (AAB) working, mainly, within bioreactors providing a quite specific and hard environment. The “omics” sciences can facilitate the identification and characterization analyses of these microbial communities, most of which are difficult to cultivate by traditional methods, outside their natural medium. In this work, two acetification profiles coming from the same AAB starter culture but using two natural raw materials of different alcoholic origins (fine wine and craft beer), were characterized and compared and the emphasis of this study is the effect of these raw materials. For this purpose, the composition and natural behavior of the microbiota present throughout these profiles were analyzed by metaproteomics focusing, mainly, on the quantitative protein profile of Komagataeibacter europaeus. This species provided a protein fraction significantly higher (73.5%) than the others. A submerged culture system and semi-continuous operating mode were employed for the acetification profiles and liquid chromatography with tandem mass spectrometry (LC-MS/MS) for the protein analyses. The results showed that neither of two raw materials barely modified the microbiota composition of the profiles, however, they had an effect on the protein expression changes in different biological process. A molecular strategy in which K. europaeus would prevail over other species by taking advantage of the different features offered by each raw material has been suggested. First, by assimilating the excess of inner acetic acid through the TCA cycle and supplying biosynthetic precursors to replenish the cellular material losses; second, by a previous assimilation of the excess of available glucose, mainly in the beer medium, through the glycolysis and the pentose phosphate pathway (PPP); and third, by triggering membrane mechanisms dependent on proton motive force to detoxify the cell at the final moments of acetification. This study could complement the current knowledge of these bacteria as well as to expand the use of diverse raw materials and optimize operating conditions to obtain quality vinegars.Clinical Trial Registration:[www.ClinicalTrials.gov], identifier [PXD031147].

Combining omics tools for the characterization of the microbiota of diverse vinegars obtained by submerged culture: 16S rRNA amplicon sequencing and MALDI-TOF MS

“…The initial acetic acid concentration was of 0.1 ± 0.1% (w/v) for AW and 0.2 ± 0.1% (w/v) for B and FW. Additional information on the nutritional composition of natural raw materials may be found in Román-Camacho et al (2022) .…”

“…A sample harvested at the final moments of the process, at the point of highest acetic acid concentration, was used as a starter culture for subsequent acetifications (B, FW). The starter culture was adapted to each raw material by a previous phase according to Román-Camacho et al (2022) .…”

“…Several factors influence the organoleptic properties and quality of these fermented products ( Mas et al, 2014 ; Ho et al, 2017 ). First, the climate and soil factors of this Mediterranean region allow the growing of native raw materials, including grapes, cereals, and other fruits which are used for obtaining some high-quality acetification substrates such as wines ( Maestre et al, 2008 ; Hidalgo et al, 2013 ; Mas et al, 2014 ; Román-Camacho et al, 2022 ). Second, the starter culture is composed of a complex community of microorganisms and does not represent an axenic culture of a single species ( Li et al, 2015 ; Trček et al, 2016 ).…”

“…Some authors have used various “omics” approaches to facilitate these studies throughout the industrial acetification process without the necessity to isolate the microorganisms while providing massive and precise information about the microbial composition and behavior during the process ( Andrés-Barrao et al, 2016 ; Trček et al, 2016 ; Wang et al, 2021 ). Recently, our previous work allowed us to characterize, by metaproteomics, the microbiota existing in a submerged acetification process employing first, a synthetic alcohol wine medium as a reference raw material ( Román-Camacho et al, 2020 , 2021 ) and then, two natural substrates ( Román-Camacho et al, 2022 ). Liquid chromatography with tandem mass spectrometry (LC-MS/MS) analyses revelated that the AAB genus Komagataeibacter was dominant throughout acetification, especially the species K. europaeus providing protein fractions above 70% of the metaproteome.…”

Effect of the type of acetic fermentation process on the chemical composition of prickly pear vinegar (Opuntia ficus‐indica)

“…Many factors affect the quality and organoleptic properties of vinegar, such as the raw material (substrate), microbial diversity (especially acetic acid bacteria) and the technological process used for its production 14,15 . There are two main biotechnological processes implicated in the production of vinegar; the first one is the fermentation of sugars to alcohols (alcoholic fermentation) by yeasts – generally Saccharomyces species – and the second process, called acetification, which is the oxidation of alcohols to acetic acid by using acetic bacteria (especially Acetobacter species, 16 although recent studies on vinegar production indicate that the most important genus, in quantitative terms, is Komagataeibacter ) 17 . In general, the methods for vinegar production range from surface culture (traditional/slow method) to submerged culture (industrial/quick method) 18 .…”