Improving Effect of Acetic Acid Bacteria (Gluconacetobacter hansenii GK-1) on sIgA and Physical Conditions in Healthy People: Double-Blinded Placebo-Controlled Study

It is known that the consumption of bacteria such as lactobacilli and bifidobacteria has beneficial effects on human immune function. Most of them are Gram-positive bacteria, and there are few reports on Gram-negative bacteria. In this study, we evaluated the effects of intake of Gluconacetobacter hansenii GK-1 (GK-1), Gram-negative acetic acid bacteria, for 12 weeks on physical condition and immune indices. We conducted a randomized, double-blind, placebo-controlled, parallel-group study in 100 healthy adults. The subjects were randomized into the GK-1 and the placebo groups. The diary-administered physical condition survey was conducted during the study period. The evaluation of salivary sIgA levels, NK-cell activity, and serum IFN-γ levels and quality of life survey was conducted before, in 6 weeks, and 12 weeks after the start of ingestion. Based on the physical condition survey, the cumulative onset-days of symptoms were significantly suppressed in the GK-1 group compared to the placebo group regarding the evaluation of 13 symptoms related to immunity, every 3 weeks. Additionally, salivary sIgA levels per hour were significantly increased in the GK-1 group compared with the placebo group at 6 and 12 weeks. Despite no significant differences in the NK-cell activity, serum IFN-γ levels or quality of life survey between the groups. Serum IFN-γ levels in the GK-1 group were significantly elevated at 12 weeks after the start of ingestion compared with those before ingestion. In conclusion, intake of GK-1 was shown to increase salivary sIgA levels and improve physical condition. This suggested that oral intake of GK-1 may help maintain the immune system.

Effects of acetic acid bacteria in starter culture on the properties of sourdough and steamed bread

Sourdough starters for making traditional steamed bread are rich in microbes.Studies have shown that,in addition to yeast and lactic acid bacteria(LAB),acetic acid bacteria(AAB)are other functional species in sourdough,but the influences of AAB on the properties of sourdough and steamed bread were rarely reported.This study aimed to assess the effects of a selected strain of acetic acid bacterium on the properties of sourdough and steamed bread.Sourdoughs and steamed breads were prepared from five different starter cultures,marked as CK(control check,with no starters),Y(only yeast),YL(yeast+LAB),YA(yeast+AAB)and YLA(yeast+LAB+AAB),and their properties were determined.The results of sour dough properties showed that the YLA sourdough had the highest total titratable acid of 14.6 mL and the lowest pH of 3.87 compared with the other groups after fermentation to 8 h;and the YLA sourdough had the greatest elasticity and viscosity.The results of quality properties of steamed bread revealed that the L*value(88.40±0.09)of the YA steamed bread was significantly higher than those of the YLA and YL steamed breads;the YLA steamed bread had the highest specific volume and the highest sensory score of 89.6±3.31 in comparison to those of the other groups;the hardness and chewiness of YLA and YA steamed breads were significantly lower than those of the other groups.Volatile compounds in the steamed breads were also determined by SPME-GC-MS.A total of 42 flavor substances were detected,including 3 kinds of alcohols,8 kinds of aldehydes,7 kinds of ketones,2 kinds of acids,15 kinds of esters,1 furan,and 6 kinds of other types of compounds,mainly alkanes and esters,followed by alcohols and aldehydes.The YLA steamed bread was richer in esters,aldehydes,and acids than those from the other treatment groups.By contrast,alkanes and aldehydes were dominant in the Y and YL steamed breads.Therefore,the flavor and quality of the steamed bread made from the YLA sourdough could be improved obviously.These results could provide references for the application of AAB in dough fermentation and the improvement of new kinds of starters.

Biological Characteristics and Research Status of Acetic Acid Bacteria for Fruit Vinegar Brewing

Fruit vinegar is a new beverage emerging in recent years because of its rich nutrition. At present, acetic acid bacteria are main strains used in the fruit vinegar production. Acetic acid bacteria are a general term for a class of bacteria that can oxidize ethanol to acetic acid. This paper mainly summarized the biological characteristics and research status of acetic acid bacteria for fruit vinegar brewing, in order to provide a theoretical basis for the selection of high-quality acetic acid bacteria for fruit vinegar brewing.

Thermoresistant, Ethanol-Resistant and Acid-Resistant Properties of Acetic Acid Bacteria Isolated from Fermented Mango Alcohol

Vinegar production is seriously affected by the sensitivity of acetic acid bacteria (AAB) to high temperature, high ethanol concentrations, and high acetic acid concentrations. The aim of this study was to investigate the thermo-ethanol-acid tolerance characters of five AAB strains (VMA1, VMA5, VMA7, VMAM, VMAO) previously isolated from fermented mango alcohol and belonging to Gluconoacetobacter genera. As result, the five AAB strains exhibited good growth and acid production at temperatures up to 45°C;they could tolerate and produce acetic acid at ethanol concentrations up to 20% (v/v). In addition, the studied strains showed growth at acetic acid concentrations up to 4.5% (w/v). Strains VMA7 and VMAO showed the highest resistance properties: they demonstrated acid production at 50°C and VMAO could even grow at 60°C;they tolerated and produced acetic acid at 25% (v/v) ethanol concentration;they showed resistance to acetic acid concentrations up to 6% (w/v). Considering all these properties, the use of these strains would seriously contribute to improving the quality of the vinegar produced and help to reduce the cooling water feeds in vinegar production especially in hot countries in the context of global warming.

不同醋酸菌对菠萝糯米果粮醋风味的影响

为探究不同醋酸菌对菠萝糯米果粮醋醋酸发酵过程和风味的影响,该研究分析了醋酸发酵过程中菌落总数、温度、总酸、不挥发酸的变化和醋液有机酸含量与挥发性成分。结果表明,与沪酿1.01相比,醋酸菌DHC23能更快适应高乙醇环境,同时能耐受更高的温度;上醅醋酸菌DHC23菌落总数峰值为1.52×10^(8)CFU/g,而沪酿1.01仅为1.95×10^(7)CFU/g;由于翻醅,醅温呈现周期性升降变化,前者峰值为42.1℃,后者仅为40.2℃。两组醋醅总酸含量均逐渐增加,不挥发酸含量均先上升后缓慢下降,而醋酸菌DHC23更有利于总酸和不挥发酸含量的提升,且使发酵时间缩短1 d。DHC23组醋液中乙酸、乳酸、柠檬酸、琥珀酸、酒石酸和焦谷氨酸含量均比沪酿1.01组含量高,且差异显著。两组醋液挥发性成分种类差异不显著,但醋酸菌DHC23有利于醛类、酸类、酯类和吡嗪类物质的生成。

桑果酒发酵过程中酸性物质与细菌群落相关性分析

基于高通量测序技术,分析主发酵阶段桑果酒细菌群落结构及其与果酒酸性物质变化之间的相关性。结果表明,两个品种桑果发酵液中酸性物质和细菌群落结构差异较大。发酵24 h,“德果1号”可滴定酸、挥发酸含量缓慢上升,其优势菌unidentified Rickettsiales相对丰度从79.74%降到17.45%,乳球菌属从0.62%升到57.24%;而“嘉陵30号”发酵24 h,可滴定酸和挥发酸含量快速升高,尤其是乙酸含量,其优势菌明串珠菌属、魏斯氏菌属分别从53.39%、3.85%降到35.20%、0.59%,乳酸杆菌属从39.11%升到52.23%。发酵液中产酸菌有醋酸杆菌属、葡糖杆菌属等醋酸菌和明串珠菌属、乳酸杆菌属、魏斯氏菌属等乳酸菌,这些细菌主要来自桑果原料,并在发酵液中细菌群落的相互作用下,相对丰度增加,产生乙酸等挥发酸。

蒙古黄芪内生细菌产IAA菌株筛选与培养条件优化

【目的】探寻蒙古黄芪内生菌的促生功能,挖掘优异微生物资源。【方法】采用前期从蒙古黄芪品系甘芪1号根中分离纯化的20株内生细菌菌株(B1~B20,GenBank序列收录号OM938262~OM938281)为研究对象,以纯培养液为对照(CK),利用Salkowski显色法对产吲哚乙酸(IAA)功能菌株鉴定,然后对优异菌株的培养条件进一步进行优化研究。【结果】甘芪1号根可培养内生细菌菌株,有12株菌株较CK有明显Salkowski显色反应,测量各菌株产IAA浓度依次为B16>B18>B10>B20>B8>B13>B11>B3>B4>B6>B1>B17,产IAA浓度范围为2.74~26.48 mg/L,平均10.10 mg/L,其中B16高稳产IAA(GenBank OM938262),平均产IAA浓度高达26.48 mg/L,极显著高于其他菌株产IAA的水平。培养条件优化显示,B16菌株培养最适温度为15~25℃,在浓度为0.1%~7%的NaCl培养基均能正常生长,最适NaCl浓度为1%,最适pH为7.0,最适碳、氮源分别为酵母提取物和蛋白胨。培养条件优化后B16增殖及IAA产能较优化前分别极显著提高28.6%和53.5%。【结论】蒙古黄芪根内生细菌中产IAA菌株比例较高,是优异豆科药用植物微生物资源宝库,且筛选到一株高稳产IAA菌株B16,经过培养条件优化可达到40.658 mg/L,是有较大的生态调控利用潜力的菌株。

广西亚热带植物根际促生菌的筛选、鉴定及促生作用研究

[目的]本文旨在从植物根际土壤中分离具有多种促生性能的菌株,并明确其促生特性和抗病效果。[方法]采用选择培养方法从植物根际土壤中筛选具有固氮、产氨、溶磷、解钾、分泌吲哚乙酸(indole acetic acid,IAA)、产铁载体和产蛋白酶等特性的菌株,通过16S rRNA对菌株分类学鉴定。测定其对小麦根腐病菌(Bipolaris sorokiniana)、小麦冠腐病菌(Fusarium gramiuearum)、黄瓜织球壳菌(Plectosphaerella cucumerina)、香蕉炭疽病菌(Colletotrichum musae)、交链格孢菌(Alternaria alternate)和尖孢镰刀菌(Fusarium oxysporum)的抑制作用,并通过盆栽试验探究植物根际促生菌对植物的促生效果。[结果]从植物根际土壤中分离细菌191株,固氮及产氨菌171株,解有机磷菌66株,解无机磷菌62株,解钾菌28株,产铁载体菌98株,产IAA菌41株,产蛋白酶菌45株。抑菌试验表明贝莱斯芽胞杆菌C32对6种致病菌均表现出较强的抑菌活性,抑菌率均在50%以上。盆栽试验结果表明,1株IAA高产菌株川大肠杆菌0208对番茄和玉米植株促生效果最为显著。与对照组相比,玉米盆栽株高、茎粗、根长、地上部鲜重和地下部鲜重分别增加21.49%、19.35%、42.98%、19.58%和56.67%,番茄盆栽分别增加53.51%、14.90%、12.28%、43.12%和48.62%。[结论]从广西亚热带植物根际土壤中筛选到多株具有高效促生和防病功能的菌株,为微生物肥料的开发提供优质菌种资源。

蓝靛果酵素粉体制备及加工特性的研究

为探究蓝靛果酵素粉的发酵工艺及其加工特性,选取蓝靛果为原料,通过单因素试验研究酵母菌添加量、发酵温度、醋酸菌添加量、发酵时间对总酚含量、总黄酮含量、花色苷含量、SOD活力的影响,结合正交试验确定最佳发酵条件。通过试验探究不同贮藏温度4,25,37℃对粉体的堆密度、滑角、休止角等加工特性的影响。结果表明,酵母菌添加量1.5%、发酵温度22℃、无氧发酵10 d,再接种醋酸菌1.5%、发酵温度34℃、有氧发酵5 d,此时感官评分最高,为93分,在此条件下总酚含量为7.63 mg/L,总黄酮含量为38.63 mg/L,花色苷含量为6.56 mg/L,SOD活力为7539 U/mL,将蓝靛果酵素经冷冻干燥避光磨粉,在4,25,37℃下测定粉体的加工特性,结果表明随着温度的升高,堆密度、滑角、休止角的变化逐渐增大,在4℃时蓝靛果酵素粉的加工特性指标最高。该试验为蓝靛果的深加工及应用提供了理论参考。

耐盐植物促生菌W-1鉴定及其对红豆草耐盐性的影响

【目的】为获得耐盐植物促生菌,从甘肃景泰一处盐碱地中的植物根系中分离出多株耐盐菌,其中部分耐盐菌具有明显的植物促生特性。【方法】在前期研究基础上,选取1株耐盐菌W-1和盐敏感植物红豆草(Onobrychis viciaefolia)为试验材料,对菌株W-1的物种分类、耐盐、耐酸碱能力和植物促生特性进行检测,并探究其对不同浓度NaCl处理下红豆草生长和生理特性的影响。【结果】耐盐菌W-1为革兰氏阳性菌、产芽孢、无荚膜、有鞭毛,16S rDNA测序及比对结果显示,菌株W-1为暹罗芽孢杆菌(Bacillus siamensis)。菌株W-1对NaCl最高耐受度为13%,pH耐受范围为4.5-8.5。菌株W-1具有溶磷、解钾、固氮、产铁载体、产吲哚-3-乙酸(indole-3-acetic acid,IAA)和1-氨基环丙烷-1-羧酸(1-aminocyclopropane-1-carboxylic acid,ACC)脱氨酶活性等多种植物促生功能。接种菌株W-1可显著提高红豆草的干重、鲜重,促进其根系生长。在100和150 mmol/L NaCl胁迫下,接种W-1可显著增加红豆草可溶性糖、可溶性蛋白、脯氨酸和叶绿素含量以及过氧化氢酶活力,降低过氧化氢含量以及叶片黄化率和死亡率,减缓盐胁迫对红豆草生长的不利影响。【结论】W-1是一株具有耐盐、耐酸碱的优良植物促生菌,可增强豆科牧草的耐盐性。

Investigation of the microbiota associated with traditionally produced fruit vinegars with focus on acetic acid bacteria and lactic acid bacteria

The microbiological properties of traditionally produced fruit vinegars,i.e.,fig,mulberry,apple and plum vinegars,supplied from different cities in Turkey were investigated.The counts of acetic acid bacteria(AAB),lactic acid bacteria(LAB)and mold-yeast for fruit vinegars were found in the range of 2.54–7.05,1.91–6.81 and 1.32–7.10 log CFU/mL,respectively.The indigenous AAB and LAB isolates were recovered from the vinegars and characterized based on a combination of phenotypic and genotypic approaches including 16S rRNA gene sequencing.In AAB three different species,Acetobacter pasteurianus,A.ghanensis and A.fabarum,and in LAB five species,Lacticaseibacillus paracasei,Lactiplantibacillus plantarum,Levilactobacillus brevis,Leuconostoc sp.and Weisella confusa were identified in the vinegar samples.It was the first study reporting the identification of A.fabarum and Leuconostoc sp.,which were isolated from fig vinegar.The results of the study showed that A.pasteurianus and L.paracasei were predominant species found in vinegar samples.The study provides potential strains which may be used as starter cultures in food industry.

Review: Gram Negative Bacteria in Brewing

Gram negative aerobic bacteria such as Acetic Acid Bacteria, which include Acetobacter and Gluconobacter, have historically caused significant problems to brewers. Although incidences of spoilage have recently reduced as a result of improvements in beer packaging, these bacteria are still a concern in dispense systems in pub breweries, public houses and cask conditioned beers. Gram negative facultative bacteria of the genus Zymomonas can spoil primed cask conditioned beer and cider. There is a wide range of Enterobacteraeceace which are found within brewery environments and they serve as indicator microorganisms for hygiene and sanitation. Gram negative strictly anaerobic bacteria such as Pectinatus and Megasphaera have recently emerged as a significant threat due to the improvement in reduction of oxygen levels in beer and an increase in production of unpasteurised beer. Pectinatus and Megasphaera are sensitive to routine cleaning agents used in breweries, but they can survive and proliferate in biofilms eventually causing spoilage of beer. This review focuses on Gram negative aerobic, facultative anaerobic and strictly anaerobic brewery related spoilage bacteria.

Effect of Inoculation with Three Phytohormone Producers Phytobacteria with ACC Deaminase Activity on Root Length of Lens esculenta Seedlings

Plant-associated bacteria that inhabit the rhizosphere may influence the plant growth by their contribution to the endogenous pool of phytohormones and by the activity of ACC deaminase to decrease the ethylene concentration. The aim of this study was to analyse the root length growth by the promoting effect of indole acetic acid producers phytobacteria with ACC deaminase activity, on inoculated seeds of Lens esculenta as synergistic effect on root elongation. In this study, although the roots of L. esculenta seedlings do not show a significant promotion, these phytobacteria could be recommended to treat plants analyzing their added inoculum to increase plant biomass and retard the effect of ethylene on cultures supplied with Tryptophan and ACC.

醋醅中优良醋酸菌的分离筛选及性能研究

醋酸菌在食醋酿造过程中不可或缺,优良菌株对改善食醋品质至关重要,因此,该实验以醋醅为研究对象,采用溴甲酚紫变色圈法分离筛选醋酸菌,并进行形态观察、生理生化试验、16S rDNA分子生物学鉴定及相关性能研究。研究从发酵过程中的醋醅分离出1株优良菌株H3。经生理生化与分子生物学鉴定,确认该菌株为果实醋杆菌(Acetobacter pomorum)。在生长量方面,菌株H3接种培养10 h后进入指数生长期,20 h到达指数生长后期。另外,菌株H3在发酵第5天产酸量高达44.16 g/L。在耐受性方面,菌株H3能耐受9%(体积分数)的乙醇和3%(体积分数)的乙酸。综上所述,通过筛选得到1株产酸量较高、耐受性良好且遗传性稳定的优良醋酸菌,为后续发酵过程中菌株的强化提供了数据支持,丰富了菌种资源,为食醋行业的发展奠定了基础。

浓香型酒醅中微生物群落及其与乙酸和乙酸乙酯的相关性分析

为了分析不同来源浓香型酒醅中微生物群落与乙酸和乙酸乙酯的相关性。采用顶空固相微萃取-气质联用法(HS-SPME-GCMS)对酒醅中挥发性组分进行检测分析,通过高通量测序分析酒醅的微生物群落组成,并分析乳酸菌和酵母菌与乙酸及乙酸乙酯的相关性。结果表明,酒醅中共检测出71种挥发性风味化合物,以酯类、酸类和醇类化合物为主,且不同来源酒醅中风味组分差异显著;微生物群落检测到10种乳杆菌和18种酵母菌。相关性分析结果表明,布氏乳杆菌(Lactobacillus brucei)与乙酸的相关系数R为0.954(P=0.012),和乙酸乙酯的相关系数R为0.890(P=0.043);扁平云假丝酵母(Candida humilis)和乙酸的相关系数R为0.957(P=0.043),和乙酸乙酯的相关系数R为0.433(P=0.211)。因此,布氏乳杆菌和扁平云假丝酵母与乙酸及乙酸乙酯含量存在显著的正相关性(P<0.05)。

7种天然发酵水果中醋酸菌的分离鉴定及其发酵特性

为筛选适合发酵果醋的优良醋酸菌,对苹果、草莓、香瓜、芒果、杏、樱桃、百香果7种天然发酵水果中的菌株进行分离,并采用生理生化试验、16S rDNA基因序列分析进行鉴定,对筛选鉴定的菌株进行耐乙醇、耐温、耐酸的发酵特性研究。结果表明,共分离得到29株菌落较大的菌株,经6 d发酵,筛选出产酸量大于30 g/L的菌株8株,并成功鉴定出8株醋酸菌。其中N8、Y21、A12、T11、C7为热带醋酸杆菌(Acetobacter tropicalis),Y11和M8为塞内加尔醋杆菌(Acetobacter senegalensi),S21为可可豆醋酸杆菌(Acetobacter fabarum)。N8、A12、T11、Y21在乙醇浓度为4%时,产酸量比其他菌株和醋酸菌AS1.41(商业菌株)高,最高可达到36.36 g/L。当温度为39℃时,这4株醋酸菌的产酸量也能达到10 g/L以上,能够耐受40 g/L的乙酸含量。结果表明N8、A12、T11、Y21具有良好的发酵产酸能力。

一株产吲哚乙酸的日本野漆树内生枯草芽孢杆菌生长条件及其促生特性研究

【目的】从日本野漆树(Toxicodendron succedaneum)组培苗分离和筛选了1株产吲哚乙酸(indole-3-acetic acid,IAA)的内生细菌(BSH-1),对其进行鉴定并分析其促生特性,为开发微生物肥料提供理论依据。【方法】通过革兰氏染色法观察菌株BSH-1的形态,结合16S rRNA基因序列分析和系统发育分析确定其分类学地位;利用生长曲线法测试菌株BSH-1的适宜生长温度、pH值和NaCl质量浓度;利用Salkowski显色法测定菌株产生IAA的能力;采用不同密度的菌株发酵液分别浸泡水稻、云南松和思茅松种子,通过统计种子萌发率以及水稻幼苗的株高、茎粗、生根数和根长等指标分析菌株的促生特性。【结果】鉴定菌株BSH-1为枯草芽孢杆菌(Bacillus subtilis),该菌在35℃、pH值为7和10 g/L NaCl条件下生长量最大。菌株BSH-1产IAA的能力达到17.27 mg/L;可通过促进水稻幼苗的株高、茎粗和生根数促进植株生长,其中株高和生根数分别比对照高9.0%和20.8%。【结论】枯草芽孢杆菌BSH-1能产生IAA,促进水稻幼苗生长,具有生物菌肥开发潜力。

当归和羌活根际促生菌筛选及特性研究

为获取对当归和羌活生长具有促生作用的促生菌(plant growth promoting rhizobacteria,PGPR),以当归、羌活的根系为研究对象,利用选择性培养基分离具有固氮、溶磷和分泌3-吲哚乙酸(IAA)能力的菌株。通过对菌株的固氮酶活性、溶磷能力及分泌IAA的能力进行测定,筛选出促生性能优良的菌株;进一步通过生理生化指标和16S rDNA序列分析相结合的方法分析优良菌株的分类地位。结果表明,共筛选到12株具有固氮酶活性的菌株,其固氮酶活性为0.30~4.04 nmol C2H4·mL^(-1)·h^(-1);6株溶解无机磷的菌株,溶磷量为290.98~420.33μg·mL^(-1);3株产IAA的菌株,IAA分泌量为10.38~18.63μg·mL^(-1)。经鉴定,溶磷特性优良的菌株属于假单胞菌属(Pseudomonas)和错玫杆菌属(Falsirhodobacter),假单胞菌属为优势菌属。综合各菌株的促生特性,筛选出2株促生性能优良的菌株:WQP-5(Pseudomonas grimontii)和MDP-8(Pseudomonas thivervalensis),为开发适用于甘肃道地药材当归与羌活专用生物菌肥提供了优良菌种。

高酸度酒精醋发酵菌种和营养盐研究进展

利用醋酸菌转化食用酒精是生产高酸度醋的主要方法。目前,我国生产的高酸度酒精醋同国际领先水平还有差距。缩小差距、生产出酸度与质量更高的酒精醋是国内行业研究的热题。酒精醋生产过程中使用的醋酸菌与营养盐是影响发酵的重要因素。文章通过对高产酸醋酸菌的选育和酒精醋营养盐的研究进行了综述,为高酸度酒精醋的工业发展提供了一定的参考依据。

草莓味黄大茶发酵饮料的开发及工艺优化

从不同产地红茶菌中分离筛选优良乙酸菌和酵母菌为发酵菌株,以大别山区黄大茶为主要原料,加入草莓果汁液,开发草莓味黄大茶发酵饮料。通过发酵工艺优化和产品调配等手段,获得最佳工艺参数:发酵菌株为乙酸菌DZ-001和酵母菌LN-001、接种体积比为2∶1、总接种体积分数为5%、起始pH值为5.5、发酵温度为30℃、发酵时间为12 d、草莓果汁添加质量浓度为4.66 g/L、结晶糖浆添加质量浓度为5.08 g/L、柠檬酸和柠檬酸钠添加质量浓度为0.20 g/L、VC质量浓度为0.02 g/L、D-异抗坏血酸钠质量浓度为0.03 g/L、草莓香精添加质量分数为0.1%。