Latest Trends in Industrial Vinegar Production and the Role of Acetic Acid Bacteria: Classification, Metabolism, and Applications-A Comprehensive Review

Microbial community and organic compounds composition analysis and the edible security of common buckwheat fermented via Kombucha consortium

This study investigates the microbial community and organic compound composition of common buckwheat fermented with a traditional Kombucha consortium. Twenty-five fungal species, nine bacterial species, five organic acids, and six phenolic compounds were identified in Common Buckwheat Kombucha (CBK). The fermentation process enriched CBK with bioactive compounds that enhanced its functional properties, including antioxidant activity and antibacterial efficacy, inhibiting pathogenic bacteria by over 81.1 %. Further research is encouraged to explore similar applications with other cereal crops.

Isolation and Characterization of a Thermotolerant Acetic Acid Bacteria Strain for Improved Zhenjiang Aromatic Vinegar Production

This study aimed to isolate a thermotolerant acetic acid bacteria (AAB) strain from Zhenjiang aromatic vinegar (ZAV) and evaluate its potential as a starter culture for high-temperature solid-state vinegar fermentation. Acetobacter pasteurianus TCBRC 103 was successfully isolated and demonstrated superior thermotolerance compared to the industrial strain A. pasteurianus Huniang 1.01. A. pasteurianus TCBRC 103 exhibited robust growth and acetic acid production at 42 °C. When employed in the solid-state fermentation of ZAV, inoculation with A. pasteurianus TCBRC 103 resulted in higher fermentation temperatures, leading to enhanced accumulation of organic acids and volatile compounds. Notably, the concentrations of flavor compounds such as isoamyl acetate, acetic acid 2-phenylethyl ester, and acetoin were significantly higher in vinegar fermented by A. pasteurianus TCBRC 103 compared to those fermented by A. pasteurianus Huniang 1.01. Orthogonal partial least squares-discriminant analysis (OPLS-DA) identified 14 discriminative flavor compounds that could serve as potential markers for distinguishing between vinegars fermented by A. pasteurianus TCBRC 103 and A. pasteurianus Huniang 1.01. These findings highlight the promising application of A. pasteurianus TCBRC 103 as a starter culture for the production of high-quality ZAV under high-temperature conditions, with implications for reducing cooling costs and improving vinegar productivity in industry.

Eco-Friendly Plant Polysaccharide-Based Sustainable Coating for Extension of Shelf Life and Removal of Pesticides in Horticulture Produce

Excessive use of chemical pesticides in farming has raised great concerns about food safety because of pesticide contamination in fruits and vegetables. Pesticides like chlorpyrifos have been linked to liver and kidney damage, respiratory problems, neurological disorders, developmental delays, endocrine disruption, and gut microbiota alterations. Moreover, rapid spoilage of perishable agricultural produce like fruits and vegetables contributes to huge postharvest losses every year and worsens food security. This study addresses these two concerns by developing an eco-friendly coating made of guar gum, vinegar, and tamarind pulp. The coating's antibacterial properties were tested against Escherichia coli and Staphylococcus aureus, while its antioxidant capacity was measured using DPPH assay. The effectiveness of the coating in reducing pesticide residues was analyzed through high-performance liquid chromatography (HPLC). The results showed antibacterial activity and high antioxidant capacity, with free radical scavenging activity of 61.33% for vinegar, 47.81% for tamarind, and 49.9% for the composite. HPLC analysis showed that the coating reduced chlorpyrifos residues on treated produce compared to the control. Moreover, the coating extended the shelf life of perishable fruits and vegetables by reducing moisture loss and microbial growth. These findings suggest that the tamarind-vinegar-guar gum composite is a sustainable solution to pesticide contamination and postharvest losses and a significant contribution to food safety and security.

Correlating Microbial Dynamics with Key Metabolomic Profiles in Three Submerged Culture-Produced Vinegars

Although vinegar is a product obtained by a well-known bioprocess from a technical point of view, the complex microbiota responsible for its production and their involvement in the organoleptic profiles are not clear yet. In this work, three acetification profiles in submerged culture using both synthetic and raw materials from Andalusia (Spain) were characterized by metagenomic (16S rRNA amplicon sequencing) and metabolomic tools (stir-bar sorptive extraction with thermo-desorption coupled to gas chromatography-mass spectrometry (SBSE-TD-GC-MS) and high-performance liquid chromatography (HPLC)). A total of 29 phyla, 208 families, and many more genera were identified, comprising bacteria and archaea as well as 75 metabolites, including minor volatile compounds, amino acids, biogenic amines, and other nitrogenous compounds. It can be concluded that Komagataeibacter and Acetobacter were not only the predominant genera but also the ones that most influenced vinegar metabolite profiles by using different metabolic strategies for mutual collaboration, and together with other microbial groups, some of them were previously practically unknown in vinegar. These results can be of interest not only to deepen the basic knowledge about vinegar but also to the vinegar industry by elucidating microbial succession and the key associated metabolites.

Vinegar - a beneficial food additive: production, safety, possibilities, and applications from ancient to modern times

Vinegar is a natural product derived from fruits or grains after being subjected to food fermentation processes. Vinegar is a beneficial food additive, preservative, and condiment. It is appreciated across the Islamic world following the Prophetic teaching where Prophet Muhammad (peace be upon him) recommended its utility, saying: "The best of condiments is vinegar". Modern medicine recognizes the health benefits, especially upon metabolism and circulation, mediated by the bioactive constituents of vinegar, including acetic acid, caffeic acid, ferulic acid, chlorogenic acid, gallic acid, p-coumaric acid, catechin, and epicatechin. Using a variety of search engines, including Google Scholar, Sci-Finder, Wiley publications, Springer Link, Scopus, MDPI, Web of Science, and PubMed, a thorough survey of the literature was carried out. To compile a comprehensive data on the various varieties of vinegar, this review highlights and updates the existing information of different vinegar-related topics including production methods, quality assessment using different quantitative analysis tools, preclinical and clinical studies, structure-activity relationship, consumption, and applications from antiquity to the present.

Changes of microbial communities and metabolites in the fermentation of persimmon vinegar by bioaugmentation fermentation

To evaluate the effects of bioaugmentation fermentation inoculated with one ester-producing strain (Wickerhamomyces anomalus ZX-1) and two strains of lactic acid bacteria (Lactobacillus plantarum CGMCC 24035 and Lactobacillus acidophilus R2) for improving the flavor of persimmon vinegar, microbial community, flavor compounds and metabolites were analyzed. The results of microbial diversity analysis showed that bioaugmentation fermentation significantly increased the abundance of Lactobacillus, Saccharomyces, Pichia and Wickerhamomyces, while the abundance of Acetobacter, Apiotrichum, Delftia, Komagataeibacter, Kregervanrija and Aspergillus significantly decreased. After bioaugmentation fermentation, the taste was softer, and the sensory irritancy of acetic acid was significantly reduced. The analysis of HS-SPME-GC-MS and untargeted metabolomics based on LC-MS/MS showed that the contents of citric acid, lactic acid, malic acid, ethyl lactate, methyl acetate, isocitrate, acetoin and 2,3-butanediol were significantly increased. By multivariate analysis, 33 differential metabolites were screened out to construct the correlation between the differential metabolites and microorganisms. Pearson correlation analysis showed that methyl acetate, ethyl lactate, betaine, aconitic acid, acetoin, 2,3-butanediol and isocitrate positively associated with Wickerhamomyces and Lactobacillus. The results confirmed that the quality of persimmon vinegar was improved by bioaugmentation fermentation.

Multidisciplinary advances in kombucha fermentation, health efficacy, and market evolution

Kombucha, a fermented tea beverage, has seen a significant rise in global popularity. This increase is attributed to its reported health benefits and extensive cultural heritage. The comprehensive review examines kombucha through microbiology, biochemistry, and health sciences, highlighting its therapeutic potential and commercial viability. Central to kombucha production is the symbiotic culture of bacteria and yeasts (SCOBY), which regulates a complex fermentation process, resulting in a bioactive-rich elixir. The study examines the microbial dynamics of SCOBY, emphasizing the roles of various microorganisms. It focuses the contributions of acetic acid bacteria, lactic acid bacteria, and osmophilic yeasts, including genera such as Saccharomyces, Schizosaccharomyces, Zygosaccharomyces, Brettanomyces/Dekkera, and Pichia. These microorganisms play crucial roles in producing bioactive compounds, including organic acids, polyphenols, and vitamins. These bioactive compounds confer therapeutic properties to kombucha. These properties include antioxidant, antimicrobial, anti-inflammatory, antidiabetic, antihypertensive, cancer prevention, hepatoprotective, and detoxifying effects. The review also explores the growing market for kombucha, driven by consumer demand for functional beverages and opportunities for innovative product development. It emphasizes the necessity of standardized production to ensure safety and validate health claims. Identifying research gaps, the review highlights the importance of clinical trials to verify therapeutic benefits. Ultimately, this study integrates traditional knowledge with scientific research, providing directions for future studies and commercial expansion, emphasizing the role of kombucha in health and wellness.

Enhancing small-scale acetification processes using adsorbed Acetobacter pasteurianus UMCC 2951 on κ-carrageenan-coated luffa sponge

Background

This study explored the utilization of luffa sponge (LS) in enhancing acetification processes. LS is known for having high porosity and specific surface area, and can provide a novel means of supporting the growth of acetic acid bacteria (AAB) to improve biomass yield and acetification rate, and thereby promote more efficient and sustainable vinegar production. Moreover, the promising potential of LS and luffa sponge coated with κ-carrageenan (LSK) means they may represent effective alternatives for the co-production of industrially valuable bioproducts, for example bacterial cellulose (BC) and acetic acid.

Methods

LS and LSK were employed as adsorbents for Acetobacter pasteurianus UMCC 2951 in a submerged semi-continuous acetification process. Experiments were conducted under reciprocal shaking at 1 Hz and a temperature of 32 °C. The performance of the two systems (LS-AAB and LSK-AAB respectively) was evaluated based on cell dry weight (CDW), acetification rate, and BC biofilm formation.

Results

The use of LS significantly increased the biomass yield during acetification, achieving a CDW of 3.34 mg/L versus the 0.91 mg/L obtained with planktonic cells. Coating LS with κ-carrageenan further enhanced yield, with a CDW of 4.45 mg/L. Acetification rates were also higher in the LSK-AAB system, reaching 3.33 ± 0.05 g/L d as opposed to 2.45 ± 0.05 g/L d for LS-AAB and 1.13 ± 0.05 g/L d for planktonic cells. Additionally, BC biofilm formation during the second operational cycle was more pronounced in the LSK-AAB system (37.0 ± 3.0 mg/L, as opposed to 25.0 ± 2.0 mg/L in LS-AAB).

Conclusions

This study demonstrates that LS significantly improves the efficiency of the acetification process, particularly when enhanced with κ-carrageenan. The increased biomass yield, accelerated acetification, and enhanced BC biofilm formation highlight the potential of the LS-AAB system, and especially the LSK-AAB variant, in sustainable and effective vinegar production. These systems offer a promising approach for small-scale, semi-continuous acetification processes that aligns with eco-friendly practices and caters to specialized market needs. Finally, this innovative method facilitates the dual production of acetic acid and bacterial cellulose, with potential applications in biotechnological fields.

Implementation of a Novel Method for Processing Proteins from Acetic Acid Bacteria via Liquid Chromatography Coupled with Tandem Mass Spectrometry

Acetic acid bacteria (AAB) and other members of the complex microbiotas, whose activity is essential for vinegar production, display biodiversity and richness that is difficult to study in depth due to their highly selective culture conditions. In recent years, liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) has emerged as a powerful tool for rapidly identifying thousands of proteins present in microbial communities, offering broader precision and coverage. In this work, a novel method based on LC-MS/MS was established and developed from previous studies. This methodology was tested in three studies, enabling the characterization of three submerged acetification profiles using innovative raw materials (synthetic alcohol medium, fine wine, and craft beer) while working in a semicontinuous mode. The biodiversity of existing microorganisms was clarified, and both the predominant taxa (Komagataeibacter, Acetobacter, Gluconacetobacter, and Gluconobacter) and others never detected in these media (Asaia and Bombella, among others) were identified. The key functions and adaptive metabolic strategies were determined using comparative studies, mainly those related to cellular material biosynthesis, energy-associated pathways, and cellular detoxification processes. This study provides the groundwork for a highly reliable and reproducible method for the characterization of microbial profiles in the vinegar industry.

Date Vinegar: First Isolation of Acetobacter and Formulation of a Starter Culture

There is a lack of scientific analysis and control over the production of date vinegar in Oman, despite its growing demand in the worldwide market. Traditional production of date vinegar may lead to elevated amounts of ethanol (≥0.5%) and reduced content of acetic acid (<4%) compared to the standard acceptable levels. This study aimed to isolate non-Gluconobacter species from date vinegar produced by spontaneous fermentation and formulate starter cultures for quick and efficient production of date vinegar. In spontaneous fermentation date vinegar samples, the highest concentration of acetic acid was 10.42% on day 50. Acetobacter malorum (5 isolates), A. persici (3 isolates), and A. tropicalis (3 isolates) were identified based on 16S rRNA gene sequences for the first time in date vinegar. For date vinegar prepared with a starter culture of Acetobacter and yeast, the highest concentration of acetic acid was 4.67%. In conclusion, spontaneous fermentation resulted in the production of date vinegar with a high concentration of acetic acid, acceptable concentrations of ethanol and methanol, and the first isolation of three Acetobacter species. The formulated starter culture produced acceptable amounts of acetic acid and the time of fermentation was reduced 10 times (from 40 days to 4 days). This can provide the basis for producing a personalized or commercial product that ensures the production of good-quality date vinegar in an easier, faster, safer, and more efficient way from low-quality and surplus dates.

Expression of a recombinant protein by an acetic acid bacterial host

We evaluated the suitability of Komagataeibacter europaeus, a vinegar production organism adept at synthetic media growth, as a host for heterologous gene expression. Cryptic plasmids (pGE1 and pGE2 derivatives) from K. europaeus strain KGMA0119 were employed as vectors for heterologous gene expression. The focus was placed on the groES promoter as a potential inducible switch. The groES promoter was fused with the EGFP gene and introduced into a pGE1 derivative to assess its suitability. Ethanol, acetic acid, and heat stresses were examined under various conditions for induction. EGFP transcription surged 600-fold when late logarithmic phase K. europaeus cells, cultured at 30 °C, endured heat stress at 40 °C, coupled with 20% acetic acid and 30% ethanol stress after an additional 6-hour cultivation. This robust induction system was then applied to express two proteins, Tth pol from the thermophilic bacterium Thermus thermophilus strain M1 and UPV230, a restriction enzyme from the acid-tolerant microorganism Ureaplasma parvum, known to cause vaginal infections and miscarriages. Both Tth pol and UPV230 were successfully expressed in K. europaeus cells and purified. The recovery of Tth pol from K. europaeus cells (480 µg protein per liter culture) was approximately half that from E. coli (960 µg protein per liter culture). In contrast, UPV230 recovery from K. europaeus cells (640 µg protein per liter culture) was nearly 10 times higher than that from Escherichia coli (66 µg protein per liter). The data highlights the potential of acetic acid bacteria as a host for producing acidophilic proteins. The shift in recognition from a 6-base sequence to a 4-base sequence of UPV230 was observed, accompanied by a change in structure as the pH transitioned from acidic pH to near-neutral pH.