Acetobacter Aceti Research Articles

Assessing Fermentation Broth Quality of Pineapple Vinegar Production with a Near-Infrared Fiber-Optic Probe Coupled with Stability Competitive Adaptive Reweighted Sampling.

In this study, the performance of a near-infrared (NIR) fiber-optic probe coupled with stability competitive adaptive reweighted sampling (SCARS) was investigated for the analysis of acetic acid, ethanol, total soluble solids, caffeic acid, gallic acid, and tannic acid in the broth of pineapple vinegar during fermentation. The NIR spectra of the broth samples in the region of 11,536-3956 cm-1 were collected during vinegar fermentation promoted by Acetobacter aceti. This continuous biological process led to changes in the concentrations of all analytes studied. SCARS provided optimized and stabilized NIR spectral variables for the construction of a partial least squares (PLS) model for each analyte using a small number of optimal variables (under 88 variables). The SCARS-PLS model outperformed the conventional PLS model, and achieved excellent accuracy in accordance with ISO 12099:2017 for the four prediction models of acetic acid, ethanol, caffeic acid, and gallic acid, with root-mean-square error of prediction values of 0.137%, 0.178%, 0.637 μg/mL and 0.640 μg/mL, respectively. In contrast, only an acetic acid content prediction model constructed via the conventional PLS method and using the whole spectral region (949 variables) could pass with acceptable accuracy. These results indicate that the NIR optical probe coupled with SCARS is an appropriate method for the continuous monitoring of multianalytes during vinegar fermentation, particularly acetic acid and ethanol contents, which are indicators of the finished fermentation of pineapple vinegar.

Scholastic modeling of pH and redox potential changes in olive tree leaf alcohol and acids containing incubation media designed for the steady growth of Acetobacter aceti and Saccharomyces cerevisiae

Modeling of pH and redox potential changes was investigated instructionally in incubation media designed for a stable growth of Acetobacter aceti and Saccharomyces cerevisiae. Olive tree leaf, phosphoric acid, vinegar, acetic acid and ethyl alcohol were used in incubation for extraction and symbiotic purposes. Structure imaging of olive tree leaf powder was performed using the Field Emission Gun – Scanning Electron Microscope (FEG-SEM). The incubation experiments were carried out at initially lowest pH and high temperatures of 30oC and 35oC for eight days in liquid state fermentation process. A steady A. aceti and S. cerevisiae growth was observed during the incubation. Increase in pH value displayed increase in redox potential in water+ phosphoric acid, vinegar+A. aceti+phosphoric acid, S. cerevisiae+A. aceti+acetic acid+phosphoric acid and S. cerevisiae+A. aceti+phosphoric acid solution processes at 30oC, and acetic acid+phosphoric acid and vinegar+phosphoric acid solution processes at 35oC. Decrease in pH value displayed decrease in redox potential in A. aceti+alcohol+phosphoric acid, vinegar+phosphoric acid, S. cerevisiae+A. aceti+acetic acid+phosphoric acid and S. cerevisiae+A. aceti+phosphoric acid solution processes at 30oC, and vinegar+A. aceti+phosphoric acid, S. cerevisiae+A. aceti+acetic acid+phosphoric acid and S. cerevisiae+A. aceti+phosphoric acid solution processes at 35 oC.

Vinegar Production using <i>Acetobacter aceti</i> Isolated from Over-ripped Bananas

The demand for food and food preservatives rises with population growth, and post-harvest fruit losses are widespread in emerging nations, particularly in Nigeria. In order to avoid the usage of chemically produced preservatives, it is essential in today's society to convert waste into vinegar, which can be utilized as an organically created preservative. In essence, vinegar production is a two-phase fermentation process that includes fermentation to alcohol and acetic acid, respectively. In this study, Baker’s yeast (Saccharomyces cerevisiae) was introduced into banana worts with a view to fermenting into alcohol (Ethanol) for 7 days, after which acetic acid bacterium (Acetobacter aceti) isolated from over-ripped bananas was inoculated into the produced alcohol to form vinegar. Analyses carried out on the produced vinegar were done using acetic acid and Fourier transform infra-red (FTIR) assays, which gave 1.4 – 4% and stretching vibrations at 1283 cm-1, 1640 cm-1, and 3260 cm-1, respectively. The findings in this study have shown that over-ripe bananas, which were previously thought of as waste, can be transformed into very valuable commodities, consequently enhancing human health and facilitating environmental safety. Results showed that over-ripe banana wort is a good raw material appropriate for fermentation- based ethanol production and vinegar manufacturing using ethanol.

Persistent Neutrophil Infiltration and Unique Ocular Surface Microbiome Typify Dupilumab–Associated Conjunctivitis in Patients with Atopic Dermatitis

To elucidate the pathogenesis of dupilumab (Dupixent®)-associated ocular surface disease (DAOSD). Prospective single-center cohort study. Twenty patients with moderate-to-severe atopic dermatitis (AD) who received dupilumab and 10 age- and sex-matched healthy controls were enrolled in the study. The study cohort underwent a thorough slit-lamp and entire-body dermatologic examination. Conjunctival swabs and smears were collected at baseline, 4 and 16 weeks after treatment initiation, and during the conjunctivitis episode. To analyse the ocular surface microbiome, 16S ribosomal RNA sequencing was performed, smears were hematoxylin and eosin stained, and serum cytokines were measured by using a multiplex immunobead assay. Composition of ocular surface microbiome and cellular component as well as serum cytokine levels. Six of the 20 patients with AD developed DAOSD after dupilumab initiation; these patients responded after a delay to treatment as quantified by Eczema Area and Severity Index and Investigator's Global Assessment score. Conjunctival smears showed massive neutrophilic infiltration and serum analysis revealed increased systemic levels of neutrophil-priming proinflammatory cytokines, in particular interleukin-1β and tumor necrosis factor α, in patients with DAOSD compared with those without it. The ocular surface microbiome of patients with DAOSD was characterized by a diverse and persistent microbial colonization, particularly by Acetobacter aceti. In contrast, microbial diversity decreased in patients with AD without DAOSD after the initiation of dupilumab treatment, especially the abundance of Staphylococcus aureus. Invitro experiments substantiated the potential role of the microbiome, showing increased growth of A.aceti and decreased growth of S.aureus in presence of dupilumab. Persistent neutrophilic infiltration and a unique microbial landscape on the ocular surface associated with elevated levels of systemic proinflammatory cytokines typify DAOSD. Proprietary or commercial disclosure may be found after the references.

Microbial Composition, Bioactive Compounds, Potential Benefits and Risks Associated with Kombucha: A Concise Review

Kombucha is a fermented tea beverage containing bioactive compounds from tea and vital compounds such as acetic acid, D-saccharic acid-1,4-lactone, and glucuronic and gluconic acids produced from the metabolic activities of bacteria and yeasts, which benefit human health. Kombucha contains a symbiotic culture of bacteria and yeast (SCOBY), which actively ferments sugar. Kombucha microbial compositions vary due to environmental conditions and the starter culture. Saccharomyces sp., Schizosaccharomyces pombe, Schizosaccharomyces sp., and Brettanomyces sp. (yeasts) and Acetobacter aceti, Komagataeibacter xylinum (formerly known as Gluconacetobacter xylinum), Gluconobacter oxydans, and Acetobacter pasteurianus (acetic acid-producing bacteria) are commonly found in kombucha. This review focused on the microbial compositions of kombucha and their functionality. Aspects discussed include: (i). developments in kombucha, (ii). microbial compositions of kombucha, (ii). microbial production of kombucha cellulose, (iv). factors influencing kombucha microbial compositions, (v). tea type and kombucha bioactive compounds, (vi). kombucha health benefits, and (v). potential risk factors of kombucha consumption. Current gaps, recommendations, and prospects were also discussed. Kombucha production using rooibos as the tea base is recommended, as rooibos is caffeine-free. Upcycling kombucha wastes, mainly SCOBY, for producing cellulose filters, improving food flavors and as a substrate in food fermentations is touched on.

Screening for antibacterial producing bacteria isolated from soil in Keffi, Nasarawa, State, Nigeria

Antibiotics are secondary metabolites that inhibit other competing cells to give competitive advantage to the microorganisms that produce them. This study is aimed at screening for antibacterial producing bacteria isolated from soil in Keffi. Standard microbiological methods were used in isolation and screening for antimicrobial of activity of crude extracts. Molecular identification of bacteria isolated were carried out using 16srRNA method. The antibacterial activity was carried out using agar well diffusion methods. The highest bacteria were Isolated from maize rhizosphere (90.0%) and the least was from groundnut rhizosphere (50.0%). Bacterial isolated and identified using 16srRNA were Pseudomonas fluorescens, Pseudomonas antarctica, Bacillus megaterium and Acetobacter aceti. The screening for antimicrobial producing bacteria showed that bacterial with laboratory code Gn3 (Pseudomonas fluorescens) showed activity against E. coli (8.57±1.01 mm), S. typhi (5.10±0.11 mm) and S. aureus (6.12±0.32 mm). Ma1 had activity against E. coli (8.57±1.01 mm), S. typhi (5.10±0.11 mm) and S. aureus (6.12±0.32 mm). Ma2 had activity against E. coli (7.56±1.33 mm) and S. typhi (4.54±0.34 mm) and Rc2 had activity only against S. aureus (12.12±0.98 mm) The Antibacterial activity of bacteria isolated and grown in complex medium with nitrogen source revealed that Pseudomonas fluorescens showed activity against the test organism E. coli (14.03±1.06mm), S. typhi (9.11±1.11mm) and S. aureus (5.12±1.02 mm). It was observed in this study that bacterial isolated from soil in Keffi were able to produce substance that that inhibit other bacterial.

Phytochemical Characterization and Sensory Evaluation of Vinegar from Melastoma malabathricum L. Flowers with Variations in Starter Concentration and Fermentation Time

Melastoma malabathricum L. or Senggani is a shrub that is easily found in open meadows. Acehnese people often use senggani as traditional medicine. The purpose of this study was to determine the phytochemical content and sensory evaluation of natural vinegar from Senggani flowers. The research design used a completely randomized design (CRD) which consisted of 5 days and 10 days of Saccharomyces administration. Both groups were added with Acetobacter aceti with concentrations of 5%, 10%, and 15% respectively in each sample. The result showed that phytochemical screening Senggani vinegar contains tannins, flavonoids, saponins, dragendrof, polyphenols, and terpenoids. The results of the organoleptic test show that the average ranking of panelists' preference for taste from the combination of the Senggani flower vinegar fermentation treatment ranges from 5.8-6.04, meaning that the taste of vinegar is slightly sour, while the panelists' preference ranking on acceptability ranges from 4.4-5, which means acceptability of panelists is neutral. The Senggani flower vinegar product with added Saccharomyces for 10 days and the fermentation of Acetobacter aceti with concentrations of 15% is the best formula preferred by the panelists. Senggani flower vinegar has the potential to be used as a health drink

Comparative Study on Effectiveness of Organic Pineapple Juice Vinegar Over Commercially Available Vinegar Using Chemical Titration Technique for Chicken Quality Analysis

Aim: The production of innovative Pineapple vinegar necessitates the use of a low-cost raw material due to the commodity’s low price.The present investigation represents the use of pineapple waste as a new substrate. Materials and Methods: In this method, the juice and core of the pineapple (Ananas comosus) can be used instead of being thrown away during processing or consumption. For 6-8 days at 25°C, the waste was fermented with Saccharomyces cerevisiae and a combination of physical and enzymatic treatments to turn it into a sugar. Two groups are taken with 8 sample size per group, G power 80%, coincidence interval will be 95%. Results: Acitric fermentation with Acetobacter aceti and the alcoholic medium took about 15 days at 30°C, and the final product had an acidity of 7.8%. Chemical titration was used to determine the amount of volatile and fixed compounds in the acetified samples, and the results showed that the concentration of acetic acid in the pineapple vinegar was significantly more than in the original wine (p=0.001). Conclusion: The metabolite profile of pineapple waste vinegar, which has a slight floral aroma, has never been studied before. It has also been shown that reusing pineapple fruits in food products with added nutritional value can significantly reduce post-harvest losses. The final pineapple vinegar had a stronger aroma due to the presence of more alcohols, aldehydes, and ketones, while the off-flavors were significantly reduced compared to the original.

Towards a 2025 Global Beer Market: The Use of Aptamers in Biosensors to Detect Acetobacter Aceti in Beer - A Biotechnological Approach to Improve Food Hygiene and Safety in Beer Developing Markets and Beyond

Aptamers were studied to see if they could be designed as a rapid detector for viable spoilage organisms in beer. SELEX was used to obtain aptamers from random libraries of oligonucleotides that could bind to A. aceti. 13 SELEX rounds were performed to get specific aptamers, whole and counter cell-SELEX was employed. Aptamers’ binding ability to A. aceti was tested by flow cytometry and confirmed to bind by synthesizing them with fluorescent labels (5’FAM). ANOVA and a one-sample test revealed significant difference in the binding ability of selected aptamers (P < 0.05). A12 and A10 showed the highest fluorescent intensity (180 and 150) for binding ability. Flow cytometry test for the binding specificity of aptamers and their truncated sequence in comparison with other organisms revealed selected aptamers to be specific to A. aceti cells having the highest mean fluorescence intensity values of 120 ± 3.8 (A12), 119 ± 5.2 (TA12), 110 ± 4.5 (A10) and 111 ± 6.2 (TA10). The best predicted folding structure of selected aptamers from mFold was determined from the Gibbs free energy (A10: ΔG = -4.40, TA10: ΔG = 0.07, A12: ΔG = - 4.96, TA12: ΔG = 0.43). Sigmaplot showed no dose-dependent relationship for detection in candidate aptamers. A12 had a low KD value of 11.22 ± 1.32 nM which further validated it as the best aptamer for detecting A. aceti in beer.

UV-C treatment: A non-thermal inactivation method for microbiological stabilisation of must and wine

UV-C treatment is discussed as an effective and efficient method to inactivate harmful microorganisms in wine and other viticultural products. In comparison to other stabilisation techniques, the application of UV-C is thought to be beneficial to reduce energy costs and to minimize SO2 addition. The object of this work was to determine the lethal UV-C dose for harmful microorganisms such as Brettanomyces bruxellensis and Acetobacter aceti. The concept of 5-log inactivation was applied and the Weibull model was used to compare different microbial and wine parameters. Microbial relevant UV-C doses and 2-fold overdose treatments and how they affected chemical and sensory changes of wine were investigated. Riesling and Pinot noir wine, which have different absorbance at 254 nm, were individually inoculated with microorganisms at different inoculation numbers. The results showed that the Weibull model is appropriate to predict the lethal UV-C dose. Already at microbially relevant doses, UV-C treatment can lead to significant changes in the colour and concentration of aroma compounds in white wine. Higher concentrations of 2-aminoacetophenone were found with increasing UV-C doses. Hence, UV-C overdosing can cause the “atypical ageing” off-flavour in wine. However, microbially relevant UV-C doses change the sensory properties of wine more towards a typical ageing character.

Impact of temperature on gluconic acid production during acetification by Acetobacter aceti.

The current approach to gluconic acid production is acetification at 30°C, a temperature that can be difficult to maintain in tropical countries. This study investigated the production of gluconic acid during acetification by Acetobacter aceti WK at high temperatures. An acid-tolerant and thermotolerant species, A. aceti WK, was used for acetification at three different temperatures, namely, 30°C (normal temperature), 37°C, and 40°C (high temperature). Acetification was performed in a 100L bioreactor with 0.15% CaCl2 for protection of the cells against high temperatures. The production of the organic acids, that is, acetic acid, gluconic acid, 2-keto gluconic acid, glucuronic acid, citric acid, succinic acid, lactic acid, and formic acid, was analyzed. Under acetification in the target total concentration of 80g/L, the highest acetic acid content (39.3g/L) was obtained at 37°C with an acetification rate of 0.3013g/L/h, while the acetic acid content and acetification rate achieved at 30°C were 31g/L and 0.3089g/L/h, respectively. Additionally, gluconic acid presented at the highest concentration of 2.17g/L. The rate of production of gluconic acid was 0.0169g/L/h at 37°C. This acetification process at 37°C will be valuable as an alternative source for gluconic acid production for commercial applications.

Comparison of the Chemical Properties of Vinegar Obtained via One-Step Fermentation and Sequential Fermentation from Dragon Fruit and Pineapple

Dragon fruit has many potential health benefits. It is inexpensive and widely cultivated in Thailand. The addition of dragon fruit to pineapple vinegar may help enhance the total phenolic compounds and antioxidant activity. This study aimed to study and compare the chemical characteristics of vinegar produced via one-step fermentation of a mixture of pineapple and dragon fruit juice from Krok Phra District of Thailand using Saccharomyces cerevisiae var. burgundy with that obtained using sequential fermentation using Saccharomyces cerevisiae var. burgundy and Acetobacter aceti. When the two fermentation methods were compared on day 20, the maximum acetic acid concentration obtained from sequential fermentation was 5.79 ± 0.25%, which was higher than that obtained in one-step fermentation (1.93%). The total phenolic compound content in the mixed fruit vinegar obtained from sequential fermentation and one-step fermentation was 228.01 and 242.2 mg/L gallic acid equivalents, respectively. The antioxidant content of the products obtained in sequential and one-step fermentations was 187.91 mg/L GAE and 209.33 µg/g of Trolox equivalents, respectively, which was consistent with the total phenolic compound content. This indicated that the acetic acid content in the mixed pineapple and dragon fruit juice vinegar obtained using sequential fermentation was higher than that obtained using one-step fermentation although its total phenolic content and the antioxidant activities were slightly lower. These observations will be useful for improving vinegar fermentation in the area.

Effects of different acetic acid bacteria strains on the bioactive compounds, volatile compounds and antioxidant activity of black tea vinegar

This study intends to produce a black tea vinegar (BTV) from low-quality bulk black tea in order to increase its consumption and added value, and to benefit from its functional characteristics. Three strains (Acetobacter sp. GDMCC1.152, Acetobacter pasteurianus GDMCC1.67, and Acetobacter aceti ATCC15973) of acetic acid bacteria (AAB) were inoculated into black tea infusion (BTI) with ethanol to produce BTV, and their effects on bioactive compounds, antioxidant activity, and volatile compounds in the vinegars were revealed. The results showed that the three strains were suitable for the production of BTV, and the vinegar quality was the best after acetic acid fermentation for 6 days. Compared with BTI, the contents of organic acids and volatile compounds and the antioxidant activity of the vinegars increased significantly. Among them, the vinegar produced by GDMCC1.152 strain had the highest content of organic acids, tea polyphenols (TPs), thearubigins (TRs), theabrownines (TBs), and volatile compounds. It also possessed the strongest antioxidant activity and a rich taste with an apple-like aroma. In summary, AAB fermentation can effectively improve the flavor and quality of BTI and produce a new healthy product with high activity, and Acetobacter sp. GDMCC1.152 is the most suitable strain for the production of BTV.

The production of wine vinegar using different types of acetic acid bacteria

This work aimed to study the properties of acetic fermentation bacteria during the acetic fermentation of wine. Attention was focused on the ability of the bacteria to metabolize selected organic substances and their suitability for wine vinegar production. For the production of wine vinegar, white wine of the variety Veltliner Green was used. Three variants were established for this experiment. The first variant was fermented with Gluconobacter oxydans, the second with Acetobacter aceti, and the third variant of vinegar production was carried out by spontaneous fermentation. During the vinegar fermentation, samples were taken at regular 24-hour intervals and subsequently analyzed. The alcohol, acetic, malic, and tartaric acid contents were monitored. The results showed that all variants showed a strong acetic and malic acid increase. Bacteria Acetobacter aceti produced the most acetic acid within nine days (25 g.L-1). This bacterium also produced the most lactic acid (18 g.L-1). Tartaric acid was also produced in all three variants, but not to the same extent as the previous two organic acids. Acetobacter aceti was found to metabolize ethanol more rapidly than Gluconobacter oxydans.

Microbial and Chemical Dynamics during Marula Wine Fermentation

Marula wine is traditionally produced through a spontaneous fermentation process and has a huge economic potential in Africa. The current study investigated the contributing microbiota and the metabolites produced during the wine fermentation process. Microbial communities were analyzed by selective cultivation and identified by biotyping and rDNA sequencing. Sugars and volatile compounds were determined with the high performance liquid chromatography and gas chromatography, respectively. Different Lactobacillus spp. were present throughout the fermentation process but dominated the earlier stages of fermentation, together with non-Saccharomyces yeasts, whereas Saccharomyces cerevisiae and acetic acid bacteria dominated the latter stages. Sucrose, glucose and fructose were detected during the early stages, while ethanol and butanol were present during the latter stages of fermentation. Interestingly, acetic acid and formic acid were detected in relatively high amounts at the latter stages of fermentation. Lactobacillus spp. and S. cerevisiae were identified as the primary contributing microbiota, and Acetobacter aceti and Acetobacter pasteuriannus were associated with the off taste and spoilage of the marula wine.

Comprehensive deciphering prophages in genus Acetobacter on the ecology, genomic features, toxin-antitoxin system, and linkage with CRISPR-Cas system.

Acetobacter is the predominant microbe in vinegar production, particularly in those natural fermentations that are achieved by complex microbial communities. Co-evolution of prophages with Acetobacter, including integration, release, and dissemination, heavily affects the genome stability and production performance of industrial strains. However, little has been discussed yet about prophages in Acetobacter. Here, prophage prediction analysis using 148 available genomes from 34 Acetobacter species was carried out. In addition, the type II toxin–antitoxin systems (TAs) and CRISPR-Cas systems encoded by prophages or the chromosome were analyzed. Totally, 12,000 prophage fragments were found, of which 350 putatively active prophages were identified in 86.5% of the selected genomes. Most of the active prophages (83.4%) belonged to the order Caudovirales dominated by the families Siphoviridae and Myroviridae prophages (71.4%). Notably, Acetobacter strains survived in complex environments that frequently carried multiple prophages compared with that in restricted habits. Acetobacter prophages showed high genome diversity and horizontal gene transfer across different bacterial species by genomic feature characterization, average nucleotide identity (ANI), and gene structure visualization analyses. About 31.14% of prophages carry type II TAS, suggesting its important role in addiction, bacterial defense, and growth-associated bioprocesses to prophages and hosts. Intriguingly, the genes coding for Cse1, Cse2, Cse3, Cse4, and Cas5e involved in type I-E and Csy4 involved in type I-F CRISPR arrays were firstly found in two prophages. Type II-C CRISPR-Cas system existed only in Acetobacter aceti, while the other Acetobacter species harbored the intact or eroded type I CRISPR-Cas systems. Totally, the results of this study provide fundamental clues for future studies on the role of prophages in the cell physiology and environmental behavior of Acetobacter.

Ozonized Oleic Acid as a New Viticultural Treatment? Study of the Effect of LIQUENSO® Oxygenate on the Carpoplane Microbial Community and Wine Microorganisms Combining Metabarcoding and In Vitro Assays

In this study, an amplicon metagenomic approach was used to determine the effect of repeated treatments with ozonized oleic acid on the microbial community of grapevine carpoplane. Differences in community composition of treated vineyards were compared to non-treated and conventionally treated samples regarding the prokaryotic and eukaryotic microbiome at two developmental stages (BBCH 83, BBCH 87). The results showed effects both on occurrence and on abundance of microorganisms and the community assembly. Wine-relevant genera such as Acetobacter and members of the former genus Lactobacillus could be identified as part of the natural microbiota. The impact of the new viticultural treatment on these organisms was assessed in liquid culture-based microtiter assays. Therefore, we investigated an array of two acetic acid bacteria (AAB), four lactic acid bacteria (LAB) and nine saccharomyces and non-saccharomyces yeasts. Brettanomyces bruxellensis, Saccharomyces cerevisiae, Pediococcus sp. and Acetobacter aceti revealed the highest sensitivities against ozonized oleic acid (LIQUENSO® Oxygenat). Culture growth of these organisms was significantly reduced at an ozonide concentration of 0.25% (v/v), which corresponded to a quarter of the concentration used in the vineyard. The metabarcoding approach in combination with complementary in vitro assays allow new insights into treatment effects on the community and species scale.

Bioprotective Effect ofPichia kluyveriandLactiplantibacillus plantarumin Winemaking Conditions

Consumer demand for wines free of, or with, reduced levels of preservatives provide new challenges for innovation in winemaking. The addition of microorganisms as bioprotective agents to avoid or reduce sulfur dioxide (SO₂) addition during winemaking is a possible intervention strategy that could be of interest to winemakers. A strain of <i>Pichia kluyveri</i> and one of <i>Lactiplantibacillus plantarum</i> were inoculated into a Nebbiolo red grape must, previously inoculated with a mix of microorganisms to mimic a grape must environment. The synergistic effect of the added strains with no, low (1 g/hL), or moderate (3 g/hL) addition of total SO₂ was explored over two vintages (2019 and 2020). Wine fermentations were monitored for microbiological (yeast and lactic and acetic acid bacterial populations) and physicochemical attributes (standard chemical parameters, chromatic characteristics, phenolic and aroma compounds). Microbiological analyses showed fewer undesired microorganisms, namely <i>Acetobacter aceti</i> and <i>Hanseniaspora uvarum</i>, independently from the strain used; this decrease occurred faster when starter cultures were combined with SO₂. Chemical analyses revealed less acetic acid and ethyl acetate in the bioprotected wines. The bioprotective ability of the starter cultures occurred in both vintages. This study examines <i>P. kluyveri</i> and <i>L. plantarum</i> as bioprotective agents in winemaking to reduce SO₂ additions during the first steps of wine production.

Preparation and hypoglycemic effects of chromium- and zinc-rich Acetobacter aceti.

BACKGROUNDAt present, there is no ideal method to cure diabetes, and there are few reports on the treatment of diabetes with probiotics.AIMTo propose a method for preparing a new type of chromium- and zinc-rich Acetobacter aceti (A. aceti) and explore its ability to enhance the hypoglycemic effects of probiotics in the treatment of diabetes. METHODS A. aceti was cultured in a liquid medium that contained chromium trichloride and zinc chloride, both at a concentration of 64 mg/mL, with the initial concentration of the bacterial solution 1 × 104 CFU/mL. After the bacterial solution had been inducted for 48 h, the culture media was changed and the induction was repeated once. The levels of chromium and zinc in the bacteria were detected by inductively coupled plasma mass spectrometry, and the contents of NADH and glucose dehydrogenase were determined using an NAD/NADH kit and glucose dehydrogenase kit, respectively. Streptozotocin was used to establish a mouse model to evaluate the hypoglycemic effects of the proposed chromium- and zinc-rich A. aceti. Ten-times the therapeutic dose was administered to evaluate its biological safety. The effect on MIN6 islet cells was also assessed in vitro. RESULTSThe levels of chromium metal, metallic zinc, NADH coenzyme, and glucose dehydrogenase in A. aceti prepared by this method were 28.58-34.34 mg/kg, 5.35-7.52 mg/kg, 5.13-7.26 μM, and 446.812-567.138 U/g, respectively. The use of these bacteria resulted in a better hypoglycemic effect than metformin, promoting the repair of tissues and cells of pancreatic islets in vivo and facilitating the growth of MIN6 pancreatic islet cells and increasing insulin secretion in vitro. Ten-times the therapeutic dose of treatment was non-toxic to mice. CONCLUSIONChromium trichloride and zinc chloride can be employed to induce the preparation of chromium- and zinc-rich A. aceti, which can then promote the hypoglycemic effect found in normal A. aceti. The bacteria biotransforms the chromium and zinc in a way that could increase their safety as a treatment for diabetes.

A new approach for the management of Escherichia coli and Klebsiella pneumonia by using cefixime-based bionanocomposite films

Purpose: The aim of this study was to assess the antibacterial potential and ex vivo skin permeation kinetics of cefixime from bionanocomposite films. Methods: The films were prepared by solvent casting method by using chitosan and starch. The fabricated films were tested for their antibacterial potential against three bacteria i.e. Escherichia coli, Klebsiella pneumonia, and Acetobacter aceti. In vitro permeation studies of cefixime from the films across rat skin was conducted using Franz diffusion cell. Results: The highest antibacterial effect was exhibited by F5 formulation (non-irradiated film) against Escherichia coli and Klebsiella pneumonia; however, antibacterial activity of the films was significantly (p < 0.05) reduced after their irradiation. F5 formulation showed the highest cumulative amount of permeated drug after 24 h, while F1 (100% chitosan) showed the lowest amount of permeated drug. Non-Fickian diffusion (anomalous) was the main mode of drug release from all films. The cross-linking of films by γ-radiations improved their mechanical properties. The percentage swelling ratio was the highest in non-irradiated films having a polymeric blend (50:50). Water uptake of irradiated films was appreciably reduced as compared to non-irradiated films. Conclusion: The synthesized bionanocomposites are promising therapeutic moieties which not only improve drug permeability across but also ameliorates antibacterial potential of cefixime.