Acetic Acid Fermentation Research Articles

Dynamics and diversity of microbial community succession in traditional fermentation of Shanxi aged vinegar

The traditional fermentation of Shanxi aged vinegar (SAV), a well-known traditional Chinese vinegar, generally involves the preparation of starter daqu, starch saccharification, alcoholic fermentation (AF) and acetic acid fermentation (AAF). Dynamics and diversity of microbial community succession in daqu and other fermentation stages were investigated by denaturing gradient gel electrophoresis (DGGE). Results showed that eight bacterial genera and four fungal genera were found in daqu. However, Staphylococcus, Saccharopolyspora, Bacillus, Oceanobacillus, Enterobacter, Streptomyces, Eurotium, Monascus and Pichia in daqu were eradicated during AF. Four bacterial genera and three fungal genera were found in this stage. Weissella, Lactobacillus, Streptococcus, Saccharomyces, and Saccharomycopsis were the dominant microorganisms in the late stage of AF. During AAF, four bacterial genera and four fungal genera were found. Weissella, Streptococcus, Klebsiella, Escherichia, and Cladosporium gradually disappeared; the dominant microorganisms were Acetobacter, Lactobacillus, Saccharomycopsis, and Alternaria in the late stage of AAF. Alpha diversity metrics showed that fungal diversity in daqu was greater than that in AF and AAF. By contrast, bacterial diversity decreased from daqu to AF and increased in the first three days of AAF and then decreased. Hence, these results could help understand dynamics of microbial community succession in continuous fermentation of traditional Chinese vinegars.

Optimization Research on Buckwheat Vinegar Fermentation Process

Buckwheat is rich in active substances with hypoglycemic effects. Submerged fermentation, as the method of brewing buckwheat vinegar, not only has the advantages of shortening production cycle, saving materials etc, but also has high functional active substances. In this study, the process of the submerged fermentation of acetic acid fermentation was optimized by the orthogonal experiments of L9 (34), which was also on the basis of single factor experiments. The results indicated that the conversion rate of acetic acid can become 95.8% when the initial alcohol at 6% (v / v), inoculum at 10%, fermentation temperature 30°Cand fermentation time 60 h.

2단계 발효에 의한 고산도 사과식초의 품질특성

본 연구에서는 사과 농축액을 이용하여 일체의 영양원을 첨가하지 않고 알코올 및 초산 발효과정으로 고산도 식초의 제조 조건을 조사하였다. 초기 알코올 함량(6, 7, 8 및 9%)을 달리하여 고산도 초산 발효액의 품질특성을 비교 분석하였다. 그 결과 알코올 함량 6% 및 7%에서 적정산도 12%의 고산도 식초 제조가 가능하였으며, 초기 알코올 함량이 낮을수록 유도기가 단축되어 수율이 높은 경향이었다. 상기 고산도 사과식초의 품질특성은 pH 2.91~3.20이고 적정산도 12.0%이며 유기산은 acetic, malic, citric 및 oxalic acid가 검출되었다. 이상의 결과 사과 농축액을 이용하여 알코올 발효 후 2단계 발효과정으로 고산도 사과식초 제조가 가능하였으나 산업적으로 활용하기 위해서는 유가식 첨가에 의한 발효기간 단축에 관한 연구가 요구되었다.

Physicochemical properties, antioxidant activity and inhibition of α-glucosidase of a novel fermented pepper (Capsiccum annuumL.) leaves-based vinegar

The aim of this study was to utilise by-product pepper leaves for vinegar production due to its nutritional value. Changes in physicochemical and functional properties in four main process from raw material (leaves) to lactic acid (juice), alcohol (wine) and acetic acid (vinegar) fermentations were evaluated and compared. Their nutritional compositions were significantly different and particularly the wine and vinegar had higher total phenol content and their expanded diversity than the juice and then leaves (P < 0.05). Difference in values for phenolic compound was highly correlated with their α-glucosidase inhibitory (AGI) and antioxidant capacities in DPPH and superoxide radical scavenging and reducing power assays (r = 0.919–0.981); vinegar ≥ wine > juice > leaves. Especially, AGI activity was greatly enhanced depending on fermentation steps beyond expectation. Thus, these data confirm that pepper leaves is a good functional source and the vinegar fermentation improved the functionality in stages.

Pomegranate juice functional constituents after alcoholic and acetic acid fermentation

In this study, a two-stage process, alcoholic and acetic acid fermentation was applied for the first time to fresh pomegranate juice to examine its effect on the phenolic content together with the antioxidant activity of the fermented product(s). The total phenol content of the juice was not greatly affected during the process. On the contrary, the total anthocyanin content fluctuated; the alcoholic product was 10-fold poorer while the end product was as rich as the fresh juice. Both fermented products had qualitatively similar HPLC-DAD-MS profile of phenolic constituents with that of the starting material but lower content (e.g. 49 and 32% of individual phenolic acid derivatives remained, respectively). The acetification product retained 44% and 37% of the fresh juice activity to scavenge the DPPH• and reduce cupric ions, respectively. These characteristics along with attractive red colour suggest that the end product is a potential source of functional constituents.

2 month of 1% Rubus coreanus vinegar drink reduces body weight and adipocyte size in dietary induced obesity rats (LB361)

The study aimed to investigate the effects of Rubus coreanus (RC) vinegar supplementation on anti‐obesity in high‐fat‐diet‐induced obesity rat. The RC vinegar was processed starting with 25°Brix of sugar concentration and was alcohol fermented at temperature of 30℃ for 10 days. The conditions for the acetic acid fermentation were 14 days of stationary fermentation at 30℃, with 6% alcohol. A total 52 4‐wk old male Sprague‐Dawley rats were fed a normal chow diet or a high‐fat diet (HFD) for 12 weeks to induce obesity and then were randomized into normal control group (NC), HFD + distilled water group (OB‐DW), HFD + 1% Acetic acid group (OB‐AA) for control, HFD + 1% RC vinegar group (OB‐RC), HFD + 15mg/d caffeine group (OB‐CAF). After 2 months, body weights, organ and fat weights, adipocyte size were analyzed. OB‐CAF rats showed most decreased body weight about 15% and OB‐AA and OB‐RC also showed decreased body weight about 6% compared to the obese rats. The adipocyte size were decreased in OB rats treated with vinegar, AA and CAF than those of OB‐DW rats. Further studies are needed to assess the health benefit of drinking vinegar. This work was carried out with the support of “Cooperative Research Program for Agriculture Science &amp;amp; Technology Development (Project No. PJ009826)” Rural Development Administration, Republic of Korea.

감귤 미숙과 식초의 품질 특성과 항산화 활성

폐자원인 감귤 미숙과를 이용한 식초를 개발하기 위하여 초산 생성능이 우수한 균주를 분리 동정하였고, 감귤 미숙과를 발효하여 식초를 제조한 후 품질 특성, 총 페놀 및 총 플라보노이드 함량, 항산화 활성을 측정하였다. 감귤슬러지 자연발효물로부터 5개 균주를 분리하였으며, 그중 초산균으로 Acetobacter fabarum(A. sp. RIC I)과 A. pomorum(A. sp. RIC II, V)이 동정되었는데, A. sp. RIC V가 초산 생성능이 가장 우수하여 감귤 미숙과즙의 초산발효 균주로 선정하였다. A. sp. RIC V를 이용하여 감귤 미숙과즙의 첨가비율을 30, 35, 40%로 달리하였을 때 발효 13일 후 산도는 각각 5.38, 5.38, 5.32%, 발효 효율은 각각 73, 72, 70%이었다. 미숙과즙 초산발효 시 산도가 5%에 도달하는 기간은 과즙첨가비율이 30%일 때는 11일, 35와 40%일 때는 9일이었다. 유리당으로 fructose와 glucose는 과즙 첨가비율이 높을수록 높은 함량을 나타내었으나 sucrose는 과즙 첨가비율과 관계없이 모두 비슷하였다. 유기산의 경우에는 미숙과 과즙의 첨가비율이 높을수록 acetic acid를 비롯한 총 유기산이 증가하였다. 감귤 미숙과 식초와 완숙과 식초의 총 페놀 함량은 각각 1,546.6과 230.9 μg GAE/mL이었고, 총 플라보노이드 함량은 각각 1,004.7과 175.1 μg QE/mL이었다. DPPH 자유라디칼 소거활성은 감귤 미숙과와 완숙과 식초가 각각 29%와 5%이었고, ABTS 소거능은 각각 62.0%와 17.9%였다. SOA 소거활성은 감귤 미숙과 식초와 완숙과 식초가 각각 60.9%와 41.7%이었고, XO 억제활성은 각각 32.5%와 5%이었다. 이상의 결과로부터 A. sp. RIC V를 이용하여 감귤 미숙과즙을 35와 40% 첨가하였을 때 초산발효가 가장 우수하였으며, 감귤 미숙과 식초는 높은 총 페놀과 총 플라보노이드 함량으로 인하여 높은 항산화 활성을 나타내어 기능성 식초로 활용할 수 있을 것이다.

Capnophilic lactic fermentation and hydrogen synthesis by Thermotoga neapolitana: An unexpected deviation from the dark fermentation model

The heterotrophic bacterium Thermotoga neapolitana produces hydrogen by fermentation of organic substrates. The process is referred to as dark fermentation and is typically complemented by production of acetic acid. Here we show that synthesis of products derived by reductive metabolism of pyruvate, mainly lactic acid, occurs to the detriment of acetic acid fermentation when the cultures of the thermophilic bacterium are flushed by saturating level of CO2. Sodium bicarbonate in a very narrow range of concentrations (∼14 mM) also causes the same metabolic shift. The capnophilic (CO2-requiring) re-orientation of the fermentative process toward lactic acid does not affect hydrogen productivity thus challenging the currently accepted dark fermentation model that predicts reduction of this gas when glucose is converted into organic products different from acetate.

Schizosaccharomyces isolation method

This study discusses the optimization of a selective and differential medium which would facilitate the isolation of Schizosaccharomyces (a genus with a low incidence compared to other microorganisms) to select individuals from this genus for industrial purposes, especially in light of the recent recommendation of the use of yeasts from this genus in the wine industry by the International Organisation of Vine and Wine, or to detect the presence of such yeasts, for those many authors who consider them food spoilers. To this end, we studied various selective differential agents based on the main physiological characteristics of these species, such as their high resistances to high concentrations of sugar, sulfur dioxide, sorbic acid, benzoic acid, acetic acid or malo ethanolic fermentation. This selective medium is based on the genus resistance to the antibiotic actidione and its high resistance to inhibitory agents such as benzoic acid. Malic acid was used as a differential factor due to the ability of this genus to metabolise it to ethanol, which allows detecting of the degradation of this compound. Lastly, the medium was successfully used to isolate strains of Schizosaccharomyces pombe from honey and honeycombs.

Analysis of volatile organic compounds from Chinese vinegar substrate during solid-state fermentation using a colorimetric sensor array

A convenient portable artificial olfaction system based on colorimetric sensor array was developed to characterize the volatile organic compounds information of vinegar’s solid fermentation substrate during acetic acid fermentation process.

Production of lactic acid by Lactobacillus paracasei isolated from button mushroom bed

A galactose fermentation bacterium producing lactose from red seaweed, which was known well to compromise the galactose as main reducing sugar, was isolated from button mushroom bed in Buyeo-Gun, Chungchugnamdo province. The lactic acid bacteria MONGB-2 was identified as Lactobacillus paracasei subsp. tolerans by analysis of 16S rRNA gene sequence. When the production of lactic acid and acetic acid by L. paracasei MONGB-2 was investigated by HPLC analysis with various carbohydrates, the strain MONGB-2 efficiently convert the glucose and galactose to lactic acid with the yield of 18.86 g/L and 18.23 g/L, respectively and the ratio of lactic acid to total organic acids was 1.0 and 0.91 g/g for both substrates. However, in the case of acetic acid fermentation, other carbohydrates besides galactose and red seaweed hydrolysate could not be totally utilized as carbon sources for acetic acid production by the strain. The lactic acid production from glucose and galactose in the fermentation time courses was gradually enhanced upto 60 h fermentation and the maximal concentration reached to be 16-18 g/L from both substrates after 48 h of fermentation. The initial concentration of glucose and galactose were completely consumed within 36 h of fermentation, of which the growth of cell also was maximum level. In addition, the bioconversion of lactic acid from the red seaweed hydrolysate by L. paracasei MONGB-2 appeared to be about 20% levels of the initial substrates concentration and this results were entirely lower than those of galactose and glucose showed about 60% of conversion. The apparent results showed that L. paracasei MONGB-2 could produce the lactic acid with glucose as well as galactose by the homofermentation through EMP pathway.

Exploring microbial succession and diversity during solid-state fermentation of Tianjin duliu mature vinegar

Tianjin duliu mature vinegar was one of famous Chinese traditional vinegars. The unique flavor and taste of vinegar are mainly generated by the multitudinous microorganisms during fermentation. In this research, the composition and succession of microbial communities in the entire solid-state fermentation were investigated, including starter daqu and acetic acid fermentation (AAF). Molds and yeasts in daqu, including Aspergillus, Saccharomycopsis and Pichia, decreased in AAF. The bacterial compositions increased from four genera in daqu to more than 13 genera in AAF. Principal component analysis showed that Acetobacter, Gluconacetobacter, Lactobacillus and Nostoc were dominant bacteria that were correlated well with AAF process. In the early fermentation period, lactic acid bacteria (LAB) decreased while acetic acid bacteria and Nostoc increased rapidly with the accumulation of total acids. Then, the abundance and diversity of LAB increased (more than 80%), indicating that LAB had important influences on the flavor and taste of vinegar.

전통정치배양에 의한 농가형 현미식초의 품질특성

We investigated the quality characteristics of brewing brown rice vinegar through a traditional static fermentation process. Accordingly, we decided to compare the physicochemical characteristics of brewing vinegar at different temperatures and filtration methods. In four to five weeks’ time, the acetic acid fermentation exhibited the highest titratable acidity and then it eventually decreased. The titratable acidity was affected by the filtration method. It was revealed that the titratable acidity was higher in the forced filtration than the traditional filtration method. Various organic acids were detected in order to initialize the fermentation stage and as the fermentation progressed, only the acetic acid could be detected. The total free amino acid content was higher at a temperature of 30°C than at 20°C. Moreover, the free amino acid content was dependent on the acetate content during the acetic fermentation process. The main bioactive substance of the γ-aminobutyric acid content was more than twice at a fermentation temperature of 30°C compared to the fermentation temperature of 20°C. Furthermore, the total amino acid and essential amino acid content at a temperature of 30°C was excellent. The quality of the brown rice vinegar via forced filtration method at a temperature of 30°C was the most excellent. Based on these results, the fermentation temperature and the use of nuruks (fermenting agent) affected the quality of the brown rice vinegar, and an appropriate method to consider its purpose is required.

Feasibility of using Hericium erinaceus as the substrate for vinegar fermentation

In this study we investigated the production of vinegar using a Hericium erinaceus fermentation. After 9 days of alcoholic fermentation, the alcohol contents reached 16% with all concentrations (1.25%, 2.5% and 5.0%) of H. erinaceus powder investigated, whereas the sugar content decreased from 25 °Brix to 14 °Brix. Also, the broth pH decreased from 4 to 3.7 and the acidity increased from 0% to 0.3%. According to the sensory evaluation, the mushroom wine produced with 5.0% H. erinaceus powder was preferred by the panel, which was then chosen for subsequent acetic acid fermentation. During the acetic acid fermentation, there was little change in pH, even though the acidity increased from 2% to 4.09%. Besides the abundant acetic acid present in the H. erinaceus vinegar, malic acid and succinic acid were also detected after 9-day of fermentation. Moreover, the H. erinaceus vinegar showed antioxidant activity comparable to other vinegar products when assayed by DPPH and ABTS.

Standardization of an Economical Bioprocess for Production of Natural Vinegar from Sugarcane

The fermentation parameters for production of fermented vinegar from sugarcane juice at 50 L scale were optimized and validated for 3 years (2010–2012) using indigenous strains S. cerevisiae strain 35 and A. aceti AC1 for ethanolic and acetic acid fermentations, respectively. The ethanolic fermentation was complete in 4 days producing ethanol between 8 and 11 % (v/v). The acetic acid fermentation was carried out by providing first 3 days of shaking, which took 23 ± 2 days for producing vinegar having 4.18–6.43 % (w/v) acetic acid. Recycling (2/3rd volume) of previous fermentation batches decreased the fermentation time to 5–9 days with an increase in acetification rate. The 81 days process developed was started with a 36 day of first batch followed by five recycled batches with a maximum of 9 days (each) thus producing 225 bottles (750 ml capacity) of sugarcane vinegar from 250 L juice at an approximate cost of Rs 45/bottle. The sugarcane vinegar produced was of standard quality with a sensory score of 8.3–8.5, had high total phenols and ascorbic acid contents, was rich in five minerals (K, Mg, Na, Ca and P) and seven amino acids (with six essential ones) and was stable for 12 months.

English

This study discusses the optimisation of a selective and differential medium which would facilitate the isolation of&nbsp;Schizosaccharomyces&nbsp;(a genus with a low incidence compared to other microorganisms) to select individuals from this genus for industrial purposes, especially in light of the recent approval of the use of yeasts from this genus in the wine industry by the International Organisation of Vine and Wine, or to detect the presence of such yeasts, for those many authors who consider them food spoilers. To this end, we studied various selective-differential agents based on the main the physiological characteristics of this species, such as its high resistance to high concentrations of sugar, sulfur dioxide, sorbic acid, benzoic acid, acetic acid or malo-ethanolic fermentation. This selective medium is based on the resistance of the genus to the antibiotic actidione and its high resistance to inhibitory agents such as benzoic acid compared to possible microorganisms which can give rise to false-positive results. Malic acid was used as a differential factor due to the ability of this genus to metabolise it to ethanol, which allows detecting of the degradation of this compound. Lastly, the medium was successfully used to isolate strains of&nbsp;Schizosaccharomyces pombe&nbsp;from honey. &nbsp; Key words:&nbsp;Schizosaccharomyces pombe, benzoic acid, actidione, differential selective medium, malic acid.

시판 과일식초의 발효방법에 따른 이화학적 특성 비교

시판 과일식초를 발효 방법에 따라 초산발효만 진행된 A타입과 알코올 및 초산발효가 진행된 B 타입으로 나누어 이화학적 특성을 비교하였다. A 타입 식초는 B 타입 식초에 비해 pH는 낮게, 총 산도는 다소 높게 확인되어 발효방법에 따른 차이를 보여주었다. 당도 및 환원당 함량은 B 타입 식초에서 비교적 높게 확인되었고, 이는 제품에 첨가된 각 과즙 함량의 차이로 사료되었다. 갈색도 및 색도의 비교에서는 B 타입에서 갈색도, 적색도, 황색도가 더 높게 측정되어 식초의 색이 더 진해지는 현상을 확인할 수 있었다. 시판 과일식초의 유리당은 fructose, glucose, sucrose, maltose의 순으로 검출되었고, 총 함량은 B 타입에서 다소 높음을 확인할 수 있었다. 시판 과일식초의 유기산은 acetic acid 외 tartaric acid, malic acid, succinic acid 등으로 구성되어 있었고 전체 함량은 A 타입 식초에서 다소 높게 확인되었다. 또한 존재하는 유기산의 함량을 통해 원료에 함유된 원료과즙의 함량을 간접적으로 추정할 수 있었다. 총 페놀 및 총 플라보노이드 함량은 B 타입 식초에서 더 높게 측정되었고, DPPH 라디칼 소거활성을 통한 항산화 활성도 유사한 경향을 나타내었다.

Changes in the bacterial community and composition of fermentation products during ensiling of wiltedItalian ryegrass and wilted guinea grass silages

To gain further insights into temperate and tropical grass ensiling, fermentation products and bacterial communities were examined at both the initial and late stages of ensiling of wilted Italian ryegrass and wilted guinea grass silages. 2,3-Butanediol and ethanol fermentation were observed in wilted Italian ryegrass silage. Enterobacteria such as Rahnella sp. and Enterobacter sp. may have been involved in fermentation; however, alcohol production was intensified after the silage enterobacterial community overwhelmed the pre-ensiled enterobacterial community. Pediococcus spp. appeared in silage stored for 4 months, when a significant increase in lactic acid content was seen compared with that at 2 months. Prolonged storage enhanced acetic acid fermentation in wilted guinea grass silage. The disappearance of Enterococcus sulfureus and appearance of Lactobacillus plantarum may have been associated with the increased acetic acid content. Although many species of enterobacteria were found in common between the pre-ensiled crop and silages of Italian ryegrass and guinea grass, marked differences were seen in the type of fermentation from the initial stages. These results indicate that the bacterial community of pre-ensiled crops may be immediately replaced by one that is adapted to ensiling environments, although metabolic changes may continue over the course of ensiling.

Adaptive mutation of Acetobacter pasteurianus SKU1108 enhances acetic acid fermentation ability at high temperature

In vitro adaptation is one of the most challenging subjects in biology to understand adaptive evolution. Microbial adaptation to temperature is not only interesting in terms of understanding the adaptation mechanism, but also useful for industrial applications. In this study, we attempted the in vitro adaptation of Acetobacter pasteurianus SKU1108 by repeating its cultivation under high-temperature acetic acid fermentation conditions. As a result, thermo-adapted strains having the higher fermentation ability than the wild-type strain were obtained. Mutations and/or disruptions in several proteins of the adapted strains were detected with NGS sequencing technology. In particular, two different adapted strains had mutations or disruptions in three specific genes in common, suggesting that these genes are essential for thermotolerance or fermentation at higher temperature. In order to clarify their involvement in thermotolerance, two of the three genes were disrupted and their phenotype was examined. The results showed that mutations of the two proteins, MarR and an amino acid transporter, are partly responsible for higher fermentation ability and/or thermotolerance. Thus, it was suggested that these elevated abilities of the adapted strains are acquired by assembling several single gene mutations including the above two mutations.

Evaluation of viability and growth of Acetobacter senegalensis under different stress conditions

Acetic acid bacteria (AAB) are used in production of vinegars. During acetic acid fermentation, AAB encounter various aggressive conditions which may lead to a variety of cellular disorders. Previous researches mainly studied the influences of different carbon sources on tolerance of AAB to ethanol and acetic acid. In this study, different techniques were used comparatively to investigate the effects of preadaptation on the ability of A. senegalensis to tolerate ethanol and acetic acid. In general, the carbon sources used for preadaptation of A. senegalensis exhibited significant effects on the tolerance of cells to stressors. Flow-cytometric assessments of preadapted cells in ethanol showed that 87.3% of the cells perform respiration after exposure to a stress medium containing 5% (v/v) ethanol and 3% (w/v) acetic acid. However, 58.4% of these preadapted cells could keep their envelope integrity under the stress condition. They could also grow rapidly (μmax=0.39/h) in the stress medium (E5A3) with a high yield (>80%). A. senegalensis grown in glucose exhibited a low tolerance to acetic acid. Analysis of their respiration capacity, membrane integrity and culturability revealed that almost all the population were dead after exposure to 5% (v/v) ethanol and 3% (w/v) acetic acid. In contrast, exposure of A. senegalensis preadapted in a mixture of glucose and acetic acid to a stress medium containing 5% (v/v) ethanol and 3% (w/v) acetic acid, exhibited an intact respiration system and cellular membrane integrity in 80.3% and 50.01% of cells, respectively. Moreover, just 24% of these cells could keep their culturability under that stress condition.In summary, cell envelope integrity, growth and culturability are more susceptible to pH and acetic acid stresses whereas respiration system is less subjected to damages under stress condition. In addition, preadaptation of A. senegalensis in a mixture of glucose and acetic acid enables it to tolerate and grow in ethanol and acetic acid.