Metagenomic analysis revealing the metabolic role of microbial communities in the free amino acid biosynthesis of Monascus rice vinegar during fermentation

Free amino acid(FAA)is the important component of vinegar that infl uences quality perception and consumer acceptance.FAA is one of the major metabolites produced by microorganisms;however,the microbial metabolic network on FAA biosynthesis remains unclear.Through metagenomic analysis,this work aimed to elucidate the roles of microbes in FAA biosynthesis during Monascus rice vinegar fermentation.Taxonomic profiles from functional analyses showed 14 dominant genera with high contributions to the metabolism pathways.The metabolic network for FAA biosynthesis was then constructed,and the microbial distribution in different metabolic pathways was illuminated.The results revealed that 5 functional genera were closely involved in FAA biosynthesis.This study illuminated the metabolic roles of microorganisms in FAA biosynthesis and provided crucial insights into the functional attributes of microbiota in vinegar fermentation.

Microbial metabolic interaction in fermentation ecosystem and cooperation in flavor compounds formation of Chinese cereal vinegar

Shanxi aged vinegar(SAV)is a famous cereal vinegar in China,which is produced through a solid-state fermentation where diverse microbes spontaneously and complex interactions occur.Here,combined with the metatranscriptomics,the microbial co-occurrence network was constructed,indicating that Lactobacillus,Acetobacter and Pediococcus are the most critical genera to maintain the fermentation stability.Based on an extensive collection of 264 relevant literatures,a transport network containing 2271 reactions between microorganisms and compounds was constructed,showing that glucose(84%of all species),fructose(67%)and maltose(67%)are the most frequently utilized substrates while lactic acid(64%),acetic acid(45%)are the most frequently occurring metabolites.Specifically,the metabolic influence of species pairs was calculated using a mathematical calculation model and the metabolic influence network was constructed.The topology properties analysis found that Lactobacillus was the key role with robust metabolic control of vinegar fermentation ecosystem and acetic acid and lactic acid were the main metabolites with feedback regulation in microbial metabolism of SAV.Furthermore,systematic coordination of positive and negative impacts was proved to be inevitable to form flavor compounds and maintain a natural microbial ecosystem.This study provides a new perspective for understanding microbial interactions in fermented food.

Effect of vinegar supplementation on patients with esophageal lesions lightly stained with Lugol’s iodine solution:Prospective single-centre trial

BACKGROUND Esophageal chromoendoscopy with iodine solution is important for detecting early esophageal cancer.The effect of routine treatment for lesions lightly stained with Lugol’s iodine solution is limited,and the addition of natural substances to a regular diet is becoming increasingly common.Vinegar has antitumor effects as reported in previous studies.AIM To evaluate whether vinegar supplementation could improve the prognosis of patients with lightly stained esophageal lesions.METHODSThis prospective single-centre trial included consecutive patients with lightly stained lesions between June 2020 and April 2022.Patients in the experimental group received increased amounts of vinegar for 6 months.The primary outcome of the study was the clinical therapeutic effect.Complications related to vinegar ingestion and adverse events were also recorded in detail.RESULTS A total of 166 patients were included in the final analysis.There was no significant difference in the baseline data between the two groups.Intention-to-treat(ITT)analysis demonstrated that the rates at which endoscopic characteristics improved were 33.72%in the experimental group and 20.00%in the conventional group(P=0.007);and the rates at which biopsy pathology improved were 19.77%and 8.75%,respectively(P=0.011).Additional vinegar consumption had a statistically protective effect on the rate at which endoscopic characteristics improved[hazard ratio(HR)_(ITT)=2.183,95%CI:1.183-4.028;HR_(per-protocol(PP))=2.307,95%CI:1.202-4.426]and biopsy pathology improved(HR_(ITT)=2.931,95%CI:1.212-7.089;HR_(PP)=3.320,95%CI:1.295-8.507).No statistically significant effect of increased vinegar consumption on preventing high-grade intraepithelial neoplasia or early cancer was observed(HR_(ITT)=0.382,95%CI:0.079-1.846;HRPP=0.382,95%CI:0.079-1.846).The subgroup analyses indicated that the overall therapeutic improvement of endoscopic characteristics and biopsy pathology seemed more obvious in older(age>60)male patients with small lesions(lesion size≤0.5 cm).Three patients in the experimental group reported acid regurgitation and heartburn.No adverse event during gastroscopy were recorded during follow-up.CONCLUSION A moderately increased ingestion of vinegar could not directly reduce the risk of esophageal cancer in the mucosa dysplasia population,but it improved the endoscopic characteristics and ameliorated the biopsy pathology to a certain extent.Further research is needed to verify the effect of nutritional intervention on precancerous esophageal lesions.

Microbiomics and metabolomics insights into the microbial regulation on the formation of flavor components in the traditional fermentation process of Chinese Hongqu aged vinegar

This study aimed to investigate microbial succession and metabolic dynamics during the traditional fermentation of Hongqu aged vinegar,and explore the core functional microbes closely related to the formation of flavor components.Microbiome analysis demonstrated that Lactobacillus,Acetobacter,Bacillus,Enterobacter,Lactococcus,Leuconostoc and Weissella were the predominant bacterial genera,while Aspergillus piperis,Aspergillus oryzae,Monascus purpureus,Candida athensensis,C.xylopsoci,Penicillium ochrosalmoneum and Simplicillium aogashimaense were the predominant fungal species.Correlation analysis revealed that Acetobacter was positively correlated with the production of tetramethylpyrazine,acetoin and acetic acid,Lactococcus showed positive correlation with the production of 2-nonanone,2-heptanone,ethyl caprylate,ethyl caprate,1-hexanol,1-octanol and 1-octen-3-ol,C.xylopsoci and C.rugosa were positively associated with the production of diethyl malonate,2,3-butanediyl diacetate,acetoin,benzaldehyde and tetramethylpyrazine.Correspondingly,non-volatile metabolites were also detected through ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry.A variety of amino acids and functional dipeptides were identified during the traditional brewing of Hongqu aged vinegar.Correlation analysis revealed that Lactobacillus was significantly associated with DL-lactate,indolelactic acid,D-(+)-3-phenyllactic acid,pimelic acid,pregabalin and 3-aminobutanoic acid.This study is useful for understanding flavor formation mechanism and developing effective strategies for the suitable strains selection to improve the flavor quality of Hongqu aged vinegar.

Inhibition of Propionibacterium acnes by refined bamboo vinegar and preparation of the slow-release system with bamboo charcoal as the carrier

Background:Acne vulgaris is one of the most common skin diseases that can significantly impact a considerable proportion of individuals over their lifetime.Objective:This study focuses on the exploration of the application potential of bamboo vinegar in cosmetics.Materials and Methods:The stock solution of bamboo vinegar is subjected to reduced-pressure distillation at different temperatures to obtain refined bamboo vinegar.Then,inhibition of Propionibacterium acnes(P.acnes)by refined bamboo vinegar is observed.Moreover,the refined bamboo vinegar is adsorbed and released with activated bamboo charcoal as the carrier.In all,this study aims to probe into the mechanism of the controlledrelease system of bamboo vinegar.Results:The results shows that the harmful substances(tar)in bamboo vinegar distilled at 70℃decreased by 94.44%,which is a more notable decrease compared with that in the stock solution.The total organic acid content in bamboo vinegar after reduced-pressure distillation is 11.840%,reaching the national standard for refined bamboo vinegar(GB/T 31734–2015).Additionally,the minimum inhibitory concentration of refined bamboo vinegar against P.acnes using the punch method is 7.90 mg/mL.This indicates that refined bamboo vinegar has the potential as a prospective raw material for formulations in anti-acne cosmetic products.Furthermore,the release rate of bamboo charcoal/bamboo vinegar in water for 15 min reaches 70.57%,which then slows down to a plateau.The slow-release behavior is agreed with the Ritger-Peppas model and is beneficial to relieve the irritation of bamboo vinegar to the skin and lengthen its bacteriostatic duration.Conclusion:The foregoing conclusions can serve as the theoretical foundation for the application of bamboo vinegar in anti-acne cosmetics.

Process Optimization of Acetic Acid Fermentation of Hawthorn Vinegar

[Objective] Fermentation process of hawthorn vinegar was investigated in order to explore the effect of process andobtain superior process of hawthorn vine- gar. [Method] Fermentation process of hawthorn vinegar was firstly optimized using Box-Behnken methodologyof 3-factor and 3-level, and the effect of process was an- alyzed. Secondly, it was also finished to build secondary multivariate regression model related to yield of acetic acid. [Results] The optimal fermentation process ob- tained by response surface methodology was as follows： inoculum size of 10%, or- iginal alcohol content of 7.0% and temperature of 30 ^（3. In optimal condition, yield of acetic acid was 51.76 g/L which was close to predicted value （51.77 g/L）. In the model, interaction of inoculum size and original alcohol content was extremely signif- icant. In contrast, interaction of others was non-significant. [Conclusion] Response surface methodology is advisable to be used for process optimization of hawthorn vinegar.

Optimization on Fermentation Conditions of Orange Vinegar by Box-behnken Design

The optimal process for orange vinegar was investigated in order to explore the effect of process parameters and obtain the superior process parameters.The process for orange vinegar was optimized using single-factor methodology and Box-behnken methodology, and the effect of process parameters was analyzed in the light of response surface plots. Results were as follows. The optimal process of alcohol fermentation was as follows： original sugar degree of 16%, yeast inoculum size of 5% and p H value of 3.5 through single-factor experiment. The optimal fermentation process of acetic acid optimized by response surface methodology was as follows： inoculum size of 8.52%, original alcohol content of 6.0% and p H value of 3.3, in the optimal condition the yield of acetic acid was 53.11 g/L. Single factor action and the interaction of two factors were presented on the yield of acetic acid.The effects of inoculum size and p H were extremely significant, and that of original alcohol content significant. The interaction of inoculum size and original alcohol content was non-significant, that of inoculum size and p H also non-significant. On contrast, original alcohol content and p H had significant interaction.

Influence of Brewing Method on Quality of Apple Vinegar

[Objective] The paper was to compare the quality of apple vinegars prepared by different methods and screen an optimum brewing method for apple vinegar production. [Methed] The quality of apple vinegar brewed by three traditional brewing methods and a new method developed by our previous work was analyzed. Three traditional methods were solid state fermentation （SSF）, liquid state fermentation （LSF） and immobilized microorganism fermentation （IMF）, and the new method was multi-microorganisms co-immobilization technology（MMCT）, which used co-immobilized beads of ethanol-producing yeast, aroma-improving yeast and lactic acid bacteria （with a ratio of 6：3：1） for alcoholic fermentation and then used immobilized acetic acid bacteria for vinegar fermentation. [Result] The general quality of apple vinegar brewed by MMCT was superior to the others. Its total acidity reached to 3.845 g/100 ml, unvolatile acidity was about 0.600 g/100 ml, amino-nitrogen was higher than 0.510 g/100 ml, and the composing of flavor compounds was almost similar to that of SSF brewed apple vinegar. [Conclusion] The MMCT method was proven to be the optimum one for high quality apple vinegar brewing and might be widely used in the future.

Preliminary study of application effect of bamboo vinegar on vegetable growth

Tiffs paper reports the effects of moso bamboo （Phyllostachys pubescense） vinegar, with different diluents, on the growth of lettuce, cole and cucumber based on field tests. The results show that moso bamboo vinegar with 500-800 times dilution had good effect on the growth of tested vegetables. The harvest of vegetables increased from 18.8%-20.2% compared with a control. The height and the weight of the average single vegetable tested also increased. The main components of moso bamboo vinegar were analyzed by GC-MS and the positive effect on the growth was, in the first instance, attributed to a synergistic effect of trace amounts of the main components of bamboo vinegar.

Effect of Wood Vinegar on Seed Germination and Water Implantation of Corn

To analyze the effect of wood vinegar on seed germination and seedling growth, the seeds of corn are dipped in wood vinegar of different densities. The results showed that significant effects were found through all the treatments on the seed germination rate, the seed germinating energy and the germinating index. The regress CUBICS curves were developed to describe the relation. The reasonable parameters range was obtained. At the same time, the corn was cultivated by wood vinegar of different densities, aiming to study the effect of wood vinegar on biomass. It showed that all treatments had obvious effects on the seedling length and dry weight aboveground, the chlorophyll and dry weight underground were not included. The research results could be used to direct the wood vinegar deeply refining process and product development.

Fermentation characteristics of vinegar residue and some natural materials

Solid state fermentation is an attractive process to produce cellulase economically due to its lower financial investment and lower operating costs. Generally available natural materials in our study included vinegar residue, wheat bran, rice bran and wheat straw. Cellulase production was carried out by solid state fermentation using these materials as the substrate of Trichoderma koningii. The ingredients of natural materials, associated with the effects of water content, time and nitrogen sources on cellulase synthesis were studied. A comparatively high cellulase activity （〉4 IU·g^-1 SDM） was obtained in the fermentation batch. The optimum culture time of vinegar residue, wheat bran and wheat straw were 72 hours, but that office bran was 60 hours. Total water contents of wheat bran, rice bran and wheat straw should not exceed 50% and that of vinegar residue should not be more than 60%. It was also shown that nitrogen salts contributed much to fermentation. （NH4）3PO4 and urea achieved good results in promoting enzyme activity.

Upgrading the Fermentation Process of Zhejiang Rosy Vinegar by Purebred Microorganisms

Purebred microorganisms were employed to upgrade the fermentation process of Zhejiang rosy vinegar. The fermentation cycle was greatly shorten from 5 months to 72 d. The transformation rate of raw materials was increased from 1:4.5 in the traditional fermentation to 1:5 or more in the upgraded fermentation. The content of organic acids in the traditional vinegar (TRV), the upgraded vinegar (UPV) and the submerged fermentation vinegar (SFV) were also investigated by HPLC. No significant difference was found regarding the proportion of phenylethanol to the total volatile components in UPV (7.47% ± 0.00324%) and TRV (7.23% ± 0.00329%), but it was significantly higher than that in SFV (2.26% ± 0.00143%). This study provides deep insight into upgrading the fermentation process of Zhejiang rosy vinegar by purebred microorganisms.

Effect of esophagus and stomach cancer-preventing vinegar on N-nitrosoproline formation in human body

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Optimization of Acetic Acid Fermentation Process of Apple Cider Vinegar

This paper studied the fermentation rules of apple cider vinegar from fruit juice,to provide a theoretical guidance for the production of apple cider vinegar.Using Fuji apples as raw materials,the process parameters(fermentation temperature,fermentation time,stirring speed,and inoculation amount)of apple cider vinegar fermentation were optimized through single-factor experiments and response surface analysis.The results indicated that the fermentation temperature had no significant effect on the total acid content of apple cider vinegar fermentation,the fermentation time had an extremely significant effect on the total acid content of apple cider vinegar fermentation,and the stirring speed and inoculation amount had a significant effect on the total acid content of apple cider vinegar fermentation.Through process optimization,the optimal process parameters for apple cider vinegar fermentation are fermentation temperature of 33℃,fermentation time of 39 h,stirring speed of 1500 r/min,and acetic acid bacteria inoculation amount of 7%.Under such conditions,the total acid content of fermented apple cider vinegar is 62.22 g/L,very close to the predicted value of the model,indicating that the process parameters of acetic acid fermentation obtained by response surface methodology(RSM)optimization are reliable and can be used for actual production prediction.

Antidiabetic and antioxidant activities of Nypa fruticans Wurmb. vinegar sample from Malaysia

Objective: To study the antidiabetic and antioxidant activities of nipa palm vinegar(NPV) used in traditional Malay medicine for treating diabetes. Methods: NPV was extracted using liquid-liquid extraction method and the obtained samples were subjected to antidiabetic studies using normal and streptozotocin-induced diabetic rat models whereas antidoxidant activities were investigated via in vitro antioxidant tests namely 2,2-diphenyl-1-picrylhydrazyl and 2,2'-azinobis-3-ethylbenzothiozoline-6-sulfonic acid free radicals scavenging activities and the reducing power assay. Results: Single administration of NPV and its extracts were not effective in both normal and diabetic rats. In intraperitoneal glucose tolerance test, NPV and its aqueous extract showed significant blood glucose lowering effect. In the sub-acute study, compared with the diabetic control, aqueous extract of NPV showed the most notable blood glucose lowering effect(56.6%) and a significant improvement in serum insulin levels(79.8%, P<0.05). To assess NPV's antioxidant activity, three in vitro antioxidant tests were employed: 2,2-diphenyl-1-picryhydrazyl and 2,2'-azinobis-3-ethylbenzothiozoline-6-sulfonic acid free radical-scavenging assays, and the reducing power assay. Ethyl acetate extract had the greatest antioxidant potential and content of phenolic and flavonoid compounds. A linear positive correlation between the antioxidant parameters was observed. Chemical profiling analysis of aqueous extract of NPV revealed the presence of acetic acid(35.25%), the main active constituent which significantly contributed to the observed antidiabetic activity. Conclusions: Aqueous extract of NPV possesses antihyperglycaemic activities comparable to the metformin, while the ethyl acetate extract precipitated significant antioxidant effects attributable to its high phenolic content. These findings suggest that antioxidant compounds of NPV do not contribute much towards the overall observed antidiabetic effect.

Inhibitory Effect of Wood Vinegar Produced from Apricot Shell on Aspergillus fumigatus

[Objectives] This study was conducted to explore the antifungal activity of wood vinegar produced from apricot shell. [Methods]The minimal inhibitory concentration（ MIC） of wood vinegar against Aspergillus fumigatus was determined on agar plates. Then,the mycelial growth and the morphology of the apical vesicles of A. fumigatus cultured in the medium supplemented with 1/2 MIC wood vinegar were observed to evaluate the effect of wood vinegar on A. fumigatus.RNA-Seq was performed to explore the antifungal mechanism of wood vinegar. [Results] The wood vinegar produced from apricot shell could inhibit the growth of A. fumigatus,with a MIC of 20 μl/ml. In the medium supplemented with 1/2 MIC wood vinegar,the mycelial growth of A. fumigatus was suppressed,some apical vesicles were incompletely developed. The gene ontology（ GO） term enrichment analysis based on RNA-Seq showed that the differentially expressed genes（ DEGs）were enriched in metabolic process,cellular process and single-organism process in the category of biological processes,cell,cell part,membrane,organelle and membrane part in the category of cellular components,catalytic activity and binding in the category of molecular function. The significantly up-regulated DEGs were mostly involved in cell,cell part,organelle,organelle part and macro molecular complex in the category of cellular component,while the significantly down-regulated DEGs were mostly involved in biological process,cellular process and single-organism process in the category of biological process,catalytic activity,binding,transporter activity,and nucleic acid binding transcription factor activity in the category molecular function. Moreover,KEGG（ Kyoto Encyclopedia of Genes and Genomes） pathway analysis showed that the DEG unigenes involved in metabolism were the most,followed by those involved in genetic information processing.[Conclusions]The results indicated that the wood vinegar produced from apricot shell might inhibit the growth of A. fumigatus by interfering with the expression of multiple genes involved in multiple signaling pathways.

Screening of Acetic Acid Producing Microorganisms from Decomposed Fruits for Vinegar Production

Acetic acid bacteria capable of growing at 30&#176C - 37&#176C were collected from various decomposed fruits available in Bangladeshi local markets in order to assess their suitability for vinegar production. Initially, 42 microorganisms were isolated from decomposed fruits like grapes, mangoes, pineapples, oranges, safeda etc. during summer when temperature reaches up to 37&#176C. Then their growths were checked in YPG medium containing various ethanol concentrations at different time point at 37&#176C. From the preliminary screening, 15 Gram negative bacterial isolates have produced halos or yellow zone around the colonies on YPG agar plate at 37&#176C which indicated acetic acid production capability by those bacteria. Furthermore, acetic acid production rates were determined by titration method and about 3 - 6.9 gm/100ml acetic acid were estimated by using 4% ethanol at 37&#176C by shaking culture for 3 days. Several biochemical analysis revealed that our collection contained huge amount of acetic acid producing bacteria and some of them could be potential candidates for vinegar production.

Feasibility of Using Corncob as the Substrate for Natural Vinegar Fermentation with Physicochemical Changes during the Acetification Process

Vinegar made from corncob, an agricultural waste product of corn, is of interest in terms of its potential as a new functional condiment with physiological characteristics derived from polyphenols. The advent of food out of waste using lignocellulosic substrates is a modern biotechnological approach to enhance sustainability. The fermentation parameters for production of fermented vinegar from corncobs were optimized. The ethanolic fermentation was completed by Saccharomyces cerevisiae in 52 hours at 36℃ producing 3.16% (v/v) ethanol. The acetic acid fermentation was carried out by Acetobacter aceti in 48 hours at 34℃for producing vinegar having 3.91% (w/v) acetic acid. Total phenolic compound of corncob wine and vinegar was reported as 49 mg/100ml and 43 mg/100ml respectively. Total flavonoid content was determined to be about 12 mg/100ml of corncob wine and 9 mg/100ml of corncob vinegar. Corncob wine and vinegar showed highest antioxidant activity with 39% and 37.94% respectively. The structural change during the two step fermentation was also confirmed by scanning electron microscope (SEM). The Hunter color value of the corn cob vinegar was also evaluated. With the current trend of shifting to natural products, corncob vinegar with better health benefits and economic significance, certainly scores high above its synthetic counterpart.

Study on the Saccharification Process of Citrus Vinegar by Fruit-Grain Mixed Fermentation

This study aimed to enhance acid production rate and yield of citrus vinegar, and improve the quality of liquid fermented with fruit juice. [ Method] The saccharification process of citrus vinegar was investigated preliminarily with fruit-grain mixed fermentation method using liquor starters as saccharif- erous agents. [Result] The results indicated that the optimal glutinous rice saccharification conditions were as follows： fruit-grain ratio 3： 1, Aspergillus niger- Monascus purpureus ratio 3： 1, saccharifieafion temperature 60℃, and saccharification time 2.5 h. Under the optimized saccharification conditions, reducing sugar content in saceharified glutinous rice reached 146.43 mg/ml; after fermentation, alcohol content in fermentation broth was 6%, amino nitrogen content was 0.44 mg/ml, and acid yield was 3.1 g/L. [ Conclusion] Citrus vinegar brewed based on the optimized technological conditions exhibited better sensory and physico-chemical properties than that brewed with pure juice.

Toxicity Test of Wood Vinegar Mixed with Different Fungicides on Rhizoctonia solani

There are few kinds of fungicides for the prevention and treatment of Rhizoctonia solani,and the excessive use of chemical fungicides can cause many hazards and toxic and side effects,not in line with the requirements of rice planting. The mixed use of wood vinegar and chemical fungicides can reduce the use of chemical fungicides,alleviate pollution and improve rice quality. In this experiment,the Horsfall method was used to study the synergistic inhibiting effect of mixture between wood vinegar and chemical fungicides on the growth of Rhizoctonia solani,as well as the optimal ratio. The results showed that when wood vinegar was mixed with Captan,the synergistic mixture ratio was 4∶6,3∶ 7 or 1∶ 9,and the toxicity ratio under mixture ratio of 4∶ 6 and 1∶ 9 was 1. 75 and 1. 99,respectively,with significant synergistic effect;when wood vinegar was mixed with Chlorothalonil,the toxicity ratio(1. 08) under mixture ratio of 8∶ 2 was greater than 1,showing additive effect.