Acetic Acid Bacteria Research Articles

Despite their significance, the diversity of acetic acid bacteria (AAB) in homemade vinegars remains understudied. This study aimed to explore the species-level diversity of AAB in homemade vinegars and to assess their community structure to better understand this microbial niche. To investigate the diversity of these bacteria, we employed recently established customized 16S-23S rDNA internal transcribed spacer (ITS) amplicon metagenomics to identify AAB at the species level. By applying Hill numbers, we calculated species richness, relative abundance, and dominance, providing a clearer understanding of the community structure of AAB in 11 homemade vinegars. Although species richness was relatively high, both relative abundance and dominance were considerably lower, suggesting a community structure dominated by a few highly abundant taxa, with most species being rare or low in abundance. The most dominant genera across most samples were Komagataeibacter and Acetobacter, both of which are known for their roles in oxidative fermentation. Several previously unreported, potentially novel species of AAB were identified, along with two potentially novel genera. This is one of the first studies to examine the diversity of AAB in homemade vinegars using a culture-independent amplicon metagenomic approach. Our findings suggest that the microbiota of homemade vinegars remains an underexplored niche and a source for novel species with biotechnological potential. The results provide valuable baseline data for future microbial studies and may help in the development of novel, customized starter cultures for the improvement and standardization of vinegar production.

Mezcal is a spirit obtained from the fermentation and distillation of juices obtained from different agave species. It is one of the distilled beverages with great sociocultural value in different regions of Mexico, and in recent years, it has also gained great economic importance. It is known to present differences in its flavour, thanks to the richness of compounds incorporated within the spirit, which vary according to the agave species used, the microbial population present and the processes involved in its manufacture. This variety reflects the richness of local traditions and the craftsmanship behind its production. The main objective of the present work was to explore parameters that could impact fungal and bacterial diversity. The microbiome of bacteria and yeasts present in fermentations in the same distillery, in two different years and with three different agave species was investigated by metataxonomic analysis obtained from the sequencing of regions V3–V4 for bacteria and ITS1 for yeasts. The results showed that the dominant fungal genera in the fermentations correspond to non-Saccharomyces yeasts (Hanseniaspora, Pichia and Zygosaccharomyces). A major finding was that Saccharomyces was not the dominant yeast in any of the 15 fermentations characterized. The dominant bacteria belong to the groups of lactic acid bacteria and acetic acid bacteria. The statistical analysis of the alpha and beta diversities shows that the main statistical differences are seen in the year of fermentation rather than in the species of agave used. Finally, the microbial consortium was composed of the same genera during the different fermentations studied; the fundamental difference was the dominant genus in each fermentation.

Kombucha is a fermented beverage containing viable microorganisms during storage. Assessing the stability of refrigerated green tea kombucha is crucial to ensure quality and regulatory compliance. This study investigated green tea kombucha produced in Brazil, stored at 4°C for 120 days. Over this period, total acidity (0.197 - 0.261 g/100 mL), pH (3.41 to 3.32), acetic acid, and total phenolics remained stable, while volatile acidity increased to 37.62 mEq/L. Sucrose decreased from 22.99 to 11.57 g/L, and populations of lactic acid bacteria (7.29 to 5.63 log CFU/mL), acetic acid bacteria (7.02 to 5.09 log CFU/mL), and yeast (7.17 to 5.42 log CFU/mL) declined, attributed to high acidity, toxic compounds, oxygen limitation, and low temperature. The kombucha retained its original properties, complying with Brazilian regulations for pH, ethanol, and volatile acidity. Sensory studies are recommended to assess how these changes affect consumer perception.

Kombucha is a functional beverage with growing popularity due to its health-promoting properties. This study aimed to evaluate the impact of herbal infusions on the quality of green tea-based kombucha. Four variants were prepared: a control (K1) and three experimental samples combining 70% green tea with 30% (v/v) Mentha spicata (K2), Hibiscus sabdariffa (K3), or Clitoria ternatea (K4). Fermentation lasted four days at 24 ± 1 °C. Physicochemical parameters, polyphenol profile (HPLC), microbiological safety, and sensory quality were assessed using QDA and electronic tongue analysis. K3 showed the highest polyphenol content (291 mg/L), especially catechins. K4 achieved the highest overall sensory quality due to its fruity aroma, balanced sweet-sour taste, and favorable microbiological profile. K2 had the lowest caffeine content (114 mg/L) and a distinct minty flavor. All samples were microbiologically safe. Herbal additives influenced fermentative microbiota: K3 had fewer acetic acid bacteria, while K4 had the highest lactic acid bacteria count. Electronic tongue analysis confirmed sensory panel results and revealed distinct taste profiles among the variants. Herbal infusions significantly enhance the nutritional and sensory properties of kombucha. Their use offers a promising strategy for developing functional beverages with tailored characteristics.

This study was to determine the spoilage microbiota of palm wine stored at room temperature in order to define appropriate strategies for shelf-life extension. For this purpose, during the storage of palm wine samples, yeast, lactic acid bacteria (LAB), and acetic acid bacteria (AAB) counts were performed. Then, species were identified by PCR-RFLP followed by sequencing and the overall bacterial community was determined by NGS (Next Generation Sequencing). The results showed that yeast, LAB and AAB counts decreased in the palm wines collected from producers after 24-48h, while they remained constant in samples collected from resellers. Furthermore, the stored palm wine microbiota was composed of several yeast species namely Saccharomyces cerevisiae, Kluyveromyces marxianus, Hanseniaspora guilliermondii, Candida parapsilosis and Brettanomyces bruxellensis. LAB species were Enterococcus durans, Limosilactobacillus fermentum, Lactiplantibacillus plantarum, Lacticaseibacillus paracasei, Fructilactobacillus durionis, Lactobacillus parafarraginis and Lactiplantibacillus pentosus. For AAB, the species were Acetobacter oryzoeni and Acetobacter pasteurianus. The species whose proportions increased steadily during storage were B. bruxellensis, C. parapsilosis, Lc. paracasei, L. fermentum and A. oryzoeni. The NGS method confirmed that Lactobacillus was predominant during storage, followed by Zymomonas and Acetobacter. Knowledge of the microorganisms present during the spoilage of palm wine and their dynamics will enable the development of preservation methods specifically targeting the microorganisms identified.

Bacterial cellulose differs from plant cellulose: its unique properties include a strong crystalline nanostructure and a high degree of polymerization. In addition, it is more pure than traditional cellulose as it contains neither lignin nor hemicellulose. These qualities make it a promising alternative to plant cellulose in several industries. Bacterial cellulose with the specific physicochemical profile can be obtained only if the metabolizing properties of its producer have been considered. This article describes the effect of nutrient medium compositions with different carbon sources, vitamins, mineral salts, and acids on the yield and properties of bacterial cellulose. Acetic acid bacteria Acetobacterium xylinum B-12429 were cultivated statically at 28°C for 72 h on the Hestrin-Schramm medium with varying carbon sources and growth factors. The highest biomass yield (4.4 g/L) was obtained on cultivation day 10 in the sample with 20.0 g/L fructose. Glucose provided a lower productivity of 3.6 g/L. The bacterial cellulose yield also proved to depend on the concentration of the main carbon source: it was at its maximum at 10%. Adding ascorbic acid and MgSO4 also catalyzed the biosynthesis. The structural profile was studied using infrared spectroscopy and scanning electron m icroscopy. It included such physicochemical properties as water-holding capacity and crystallinity indices Iα and Iβ. The biofilms produced from the media fortified with xylose and sorbitol demonstrated excellent water-holding capacity; all the samples demonstrated a stable crystalline structure regardless of the carbon source. The composition of the nutrient media had a significant effect on the yield and quality of biosynthesis. An optimized nutrient composition was able to boost biosynthesis, making the method applicable to industrial scales of high-quality bacterial cellulose production.

BackgroundSpontaneous fermentation is among the oldest food preservation methods, with evidence of enhancing the nutritional and sensorial qualities of products and the synthesis of health-promoting compounds. However, the bacterial communities responsible for these transformative changes remain poorly understood, notably across diverse indigenous Ghanaian substrates, including grains and starchy roots, tubers, and plantains.MethodThe study aimed to examine bacterial community diversity in the spontaneous fermentations of selected Ghanaian raw materials for complementary food, namely maize, millet, sorghum, sweetpotato, cassava, soybean and plantain. Fermentation lasted 48 h, with samples collected at 6-h intervals. The pH and total titratable acidity (TTA) were determined using standard protocols over the fermentation period. DNA was extracted directly from the fermented food samples using ZymoBIOMICS™ kits, and full-length 16 S rDNA sequencing was performed on the Pacific Biosciences Sequel IIe long-read sequencing platform. Data processing involved DADA2 and taxonomic classification against the SILVA database v138.1, with analysis conducted using R version 4.4.3.ResultsFermented cereals exhibited increasing bacterial diversity over time, dominated by Weissella confusa, Enterococcus hirae, and Pediococcus acidilactici. Soybean fermentation showed distinct microbial communities with fluctuating diversity. Starch-rich roots, tubers, and plantain supported the growth of Leuconostoc mesenteroides, Weissella confusa, Gluconobacter frateurii, Fructobacillus fructosus, and Pediococcus pentosaceus. Enterococcus faecium favored acidic conditions, while Weissella confusa and Leuconostoc mesenteroides adapted to the fluctuating pH conditions in specific crop substrates.ConclusionThe fermented flours showed increased bacterial diversity over time, dominated by lactic acid bacteria (LAB) and acetic acid bacteria. The fermentation patterns among the plant-based substrates differed in terms of bacterial behavior and their response to pH and TTA over time. Understanding the bacterial community dynamics not only enhances our knowledge of bacterial ecosystems but also offers a foundation for refining the safety, consistency, and nutritional quality of fermented foods.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12866-025-04342-4.

Interaction effects of fumaric acid, pH and ethanol on the growth of lactic and acetic acid bacteria in planktonic and biofilm states.

Making yogurt with the ant holobiont uncovers bacteria, acids, and enzymes for food fermentation

Metagenomic and meta-metabolomic analysis of traditional Korean rice vinegar productions shows a large variability between producers.

Cellulose-producing acetic acid bacteria from corozo fruit (Bactris guineensis): isolation and characterization

Fermentation is a crucial stage in the production of washed mild coffees, as it enables the generation of compounds that influence overall quality. The conditions to optimize this process are still unknown. This study evaluated the effects of fermenting coffee fruits and depulped coffee under two conditions: an open tank (semi-anaerobic-SA) and a closed tank (self-induced anaerobic fermentation, SIAF) over 192 h. Samples were taken every 24 h using a sacrificial bioreactor. A randomized complete block design with a factorial arrangement (2 × 2 + 1), plus a standard control, was employed, incorporating two factors: coffee type and fermentation condition. High-throughput sequencing of 16S and ITS amplicons identified an average of 260 ± 71 and 101 ± 24 OTUs, respectively. Weisella was the dominant lactic acid bacteria, followed by Leuconostoc and Lactiplantibacillus. Acetic acid bacteria, mainly Acetobacter, were more abundant under semi-anaerobic conditions. The yeast genera most affected by the fermentation condition were Pichia, Issatchenkia, and Wickerhamomyces. Repeated measures analysis revealed significant differences in pH, glucose consumption, lactic acid production, dry matter content, embryo viability, and the percentage of healthy beans. Principal component analysis was used to develop an index that integrates physical, physiological, and sensory quality variables, thereby clarifying the impact of each treatment. Samples from shorter fermentation times and SIAF conditions scored closest to 1.0, reflecting the most favorable outcomes. Otherwise, samples from longer fermentation times in both depulped and coffee fruits scored 0.497 and 0.369, respectively, on the SA condition. These findings support technically and economically beneficial fermentation strategies.

Cacao fermentation is a spontaneous process in which microorganisms play a key role in the development of distinctive chocolate flavors. The microbiota acting during cacao fermentation has been routinely characterized by culture-based techniques and next-generation sequencing using Illumina’s platform. However, the potential of in situ sequencing technologies to monitor microbial dynamics during cacao fermentation has not been assessed. In this study, cacao bean samples were collected at 0, 24, 48, 72, and 96 h after the start of the fermentation. Total DNA was extracted, and sequencing libraries were prepared for further sequencing using Illumina’s and Nanopore’s MinION sequencing platforms. Additionally, microorganisms were isolated using traditional culture-based methods. At the order and family taxonomic levels, Illumina and MinION sequencing revealed similar microbial composition in the samples. However, discrepancies were observed at the genus and species levels. In this sense, Illumina sequencing revealed a predominance of Limosilactobacillus, Levilactobacillus, Lactiplantibacillus, Frauteria, Saccharomyces and Acetobacter, while MinION sequencing showed a prevalence of Escherichia, Salmonella, Liquorilactobacillus, Lentilactobacillus, Acetobacter and Komagataeibacter during fermentation. The three methods were consistent in detecting the major yeast (Saccharomyces cerevisiae), lactic acid bacteria (Lactiplantibacillus plantarum, Leuconostoc pseudomesenteroides, Levilactobacillus brevis, Liquorilactobacillus mali, and Lentilactobacillus hilgardii) and acetic acid bacteria (Acetobacter pasteurianus) species during fermentation. Functional analysis based on a hybrid assembly of Illumina and MinION data revealed the roles of lactic acid bacteria and acetic acid bacteria in the metabolism of carbohydrates, amino acids, and secondary metabolites such as polyphenols and theobromine. This study represents the first report assessing the applicability of MinION sequencing for the characterization of microbial populations during cacao fermentation, demonstrating its potential as a complementary tool to established sequencing platforms.

The use of acid whey as a medium is an innovative approach to bacterial cellulose (BC) biosynthesis in co-cultures of acetic acid bacteria with lactic acid bacteria. The aim of this study was to evaluate the possibility of obtaining BC in acid whey by co-culturing K. xylinus with selected strains of lactic acid bacteria and comparing the properties of this biopolymer with BC obtained in K. xylinus monoculture. The K. xylinus + Lb. acidophilus co-culture yielded 2.19g·L-1 of BC, which was 125% more than the K. xylinus monoculture. Additionally, K. xylinus in co-culture with Lb. acidophilus increased the degradation temperature of BC to 361°C compared to 303°C for BC obtained in monoculture. The BC obtained in the co-cultures showed better mechanical properties. BC obtained in co-culture with Lb. delbrueckii showed more than twice the Young's modulus than BC from monoculture. Moreover, strain at break BC from co-culture with Lb. acidophilus and stress at break BC from co-culture with Lb. helveticus were 72% and 54% higher, respectively, than BC obtained from monoculture K. xylinus. In this study, it was shown that conducting acetic-lactic co-cultures increased the efficiency of BC biosynthesis and improved its properties. Moreover, this study has shown that acid whey is a sufficient and complete substrate for obtaining BC. Results presented in this paper indicate new possibilities for the management of this side product. KEY POINTS: • The K. xylinus + Lb. acidophilus co-culture produced 125% more cellulose than the monoculture. • High lactic acid content and low pH of acid whey enhance cellulose biosynthesis. • Acetic acid-lactic acid co-cultures improved the mechanical properties of cellulose.

Fermented foods have been consumed for thousands of years and have been used as a model system to study community succession and other ecological questions. Additionally, cooking classes offer opportunities to learn about food preparation and history. In the present study, scientists and chefs delivered cooking-class style workshops in which participants learned the recipes of one of three fermented foods and the microbial ecology within these foods. Participants prepared jars of chow chow, kimchi, or kombucha to set up experiments to study microbial community succession and pH changes. The fermented foods were also used to test the following hypotheses: that increasing the number of substrates results in increased alpha diversity, and that phylogenetically diverse substrates will lead to greater beta diversity among microbial communities. Microbial communities contained lactic and acetic acid bacteria described previously in fermented foods, and indicator species were identified for cabbage and radish substrates in kimchi. Finally, we qualitatively comment on the experience of developing workshops with chefs and the use of participatory science in these experiments.IMPORTANCEThe present study demonstrates the utility of using fermented foods as an inexpensive and effective tool to investigate ecological phenomena and engage the public in microbiology and ecology through cooking-class style workshops. We also model a creative, interdisciplinary collaboration between scientists and chefs.

Indigenous Mexican fermented beverages, such as pulque, colonche, tepache, and water kefir, are pillars of the country’s cultural and gastronomic heritage. Their sensory attributes and health-promoting properties arise from complex microbial consortia, in which lactic acid bacteria (LAB), mainly Lactobacillus and Leuconostoc, acetic acid bacteria (AAB), primarily Acetobacter, and yeasts such as Saccharomyces and Candida interact and secrete exopolysaccharides (EPSs). Dextran, levan, and heteropolysaccharides rich in glucose, galactose, and rhamnose have been consistently isolated from these beverages. EPSs produced by LAB enhance the viscosity and mouthfeel, extend the shelf life, and exhibit prebiotic, antioxidant, and immunomodulatory activities that support gut and immune health. Beyond food, certain EPSs promote plant growth, function as biocontrol agents against phytopathogens, and facilitate biofilm-based bioremediation, underscoring their biotechnological potential. This review integrates recent advances in the composition, biosynthetic pathways, and functional properties of microbial EPSs from Mexican fermented beverages. We compare reported titers, outline key enzymes, including dextransucrase, levansucrase, and glycosyltransferases, and examine how fermentation variables (the substrate, pH, and temperature) influence the polymer yield and structure. Finally, we highlight emerging applications that position these naturally occurring biopolymers as sustainable ingredients for food and agricultural innovation.

Kombucha, a fermented tea beverage, is gaining popularity due to its rich content of bioactive compounds and associated health benefits. Kombucha fermentation involves a complex microbial consortium, including acetic acid bacteria, lactic acid bacteria, and yeasts, that works synergistically to enhance its nutritional and functional properties. Key compounds produced during fermentation provide antioxidant, anti-inflammatory, and antimicrobial benefits. Despite its well-documented health-promoting properties, limited research exists on how human digestion influences the stability and functionality of kombucha bioactive components. This study investigated how digestion impacts kombucha made from green and black teas, focusing on free amino acid content, antioxidant activity, antimicrobial potential, and microbiota viability. Results showed that digestion significantly increased free amino acids, as fermentation released peptides suitable for gastrointestinal digestion. However, L-theanine, a beneficial tea compound, was no longer detectable after fermentation and digestion, suggesting limited bioaccessibility. Digested kombucha exhibited higher antioxidant activity and stronger antimicrobial effects compared to undigested tea. Moreover, culture-dependent and PMA-based sequencing confirmed the survival of viable microbial strains through simulated gastrointestinal conditions, suggesting the potential of kombucha as a source of live, functional microbes. These findings support the role of kombucha as a natural functional beverage whose health benefits not only persist but may be enhanced after digestion.

Leaching of aluminium from post-consumer beverage packaging residual PolyAl using biogenic organic acids: Towards low-cost, sustainable recycling.

This study evaluated the effect of acetic acid fermentation added to coffee concentrate using the concentrate of fermented coffee bean ethanol extract. The ethanol concentration that can extract a high content of coffee’s active ingredients (caffeine, chlorogenic acid) was 50% (v/v). The ethanol extract from coffee was concentrated to a solid content of 7.94% (w/v) and added at a concentration of 7-10% to prepared coffee liquor containing 6% ethanol. Additionally, 20% seed vinegar was introduced to initiate acetic acid fermentation. During the fermentation period of coffee vinegar with different concentrations of coffee extracts (CVCE1-CVCE4) lasting 30 days, the viable cell counts, physicochemical properties (soluble solid contents, pH, and total acidity), organic acids, free sugars, and ethanol content were measured. The number of viable cells was 4.50-7.33 log CFU/mL on the 10th day of fermentation, and the growth of bacteria tended to decrease as the content of coffee solids increased. As acetic acid fermentation progresses, the ABTS and DPPH radical scavenging activities of coffee vinegar decreased, while pancreatic lipase inhibition activity increased. The analysis showed that the amount of coffee extract concentrate added affects the fermentation characteristics of acetic acid bacteria, resulting in a difference in the functionality of coffee vinegar.

Despite its nutritional value, Diospyros mespiliformis is an underexploited fruit in Ivory Coast. This study was conducted with the aim of enhancing this fruit. Thus, according to the analysis, the precise quantities of fruits were collected in Korhogo (northern Côte d'Ivoire) and the physico-chemical properties determined. Endogenous acetic acid bacteria from the fruit were then isolated on selective medium and identified using phenotypic and biochemical methods. Their acidification capacity and resistance to different stresses were tested using reference methods. The strains with the best technological potential were selected by the ascending classification technique. The results showed that the fruit has an acidic pH (2,85 ± 0,01) with a soluble dry extract of 5°Brix, high water content (74,97 ± 0,86 %) and vitamin C (5,06 ± 2,16 mg/100 g). Out of a set of thirty-two (32) isolates of acetic bacteria, nine (09) or (28.1%) showed a strong ability to produce acetic acid in solid media. However, among these nine (09) isolates, four (04) named BAD11, BAD14, BAD23 and BAD24 presented the best resistance to different stresses. Thus, these four (04) isolates identified as Acetobacter sp. with highest acetic acid productions and best other physiological properties could be used in biotechnological processes, particularly in the vinegar industry.