传统面食发酵剂中菌群多样性的研究

我国传统面食发酵剂的使用具有悠久的历史,其制作的馒头、包子等发酵食品因风味独特而深受大家喜爱,但对传统面食发酵剂中微生物菌群的研究却非常薄弱。本文以河南地区的传统面食发酵剂为对象,采用分离培养及分子鉴定技术对其微生物生态多样性进行了研究。通过对微生物基本形态特征观察结合生理生化试验及分子鉴定技术,将分离到的30株酵母菌鉴定为4类,其中11株为酿酒酵母(Saccharomyces cerevisiae),6株为异常毕赤酵母(Pichia anomala),8株为东方伊萨酵母(Issatchenkia orientalis),5株为扣囊复膜酵母(Saccharomycopsis fibuligera),其中酿酒酵母(Saccharomyces cerevisiae)为优势酵母菌种;分离的28株乳酸菌中13株为植物乳杆菌(Lactobacillus plantarum),8株为粪肠球菌(Enterococcus faecalis),7株为干酪乳杆菌(Lactobacillus casei),其中植物乳杆菌(Lactobacillusplantarum)为优势乳酸菌。此外,样品中还分离到了一株霉菌,经鉴定为米根霉(Rhizopus oryzae)。     

枣阳酸浆水中乳酸菌的可培养多样性及其分离方式评价

采用变形梯度凝胶电泳(DGGE)对浆水样品细菌群落进行分析,使用6种常用的乳酸菌分离方式对酸浆水中的乳酸菌进行了分离与鉴定,并对这些方法的分离效果进行了评价。结果表明,酸浆水样品中乳酸菌的数量约为5×106~2.5×108 cfu/mL,不同来源的浆水样品中乳酸菌数量差异较大。通过这6种培养方式共分离得到90株乳酸菌。经过鉴定,它们是德氏乳杆菌(Lactobacillus delbrueckii)、发酵乳杆菌(Lactobacillus fermentium)、副干酪乳杆菌(Lactobacillus paracasei)、植物乳杆菌(Lactobacillus plantarum)、鼠李糖乳杆菌(Lactobacillus rhamnosus)与玉米乳杆菌(Lactobacillus zeae)。在6种乳酸菌分离方式中,非增菌法中厌氧罐-厌氧袋法、厌氧工作站(10% H₂,10% CO₂,80% N₂)及增菌法对酸浆水中的乳酸菌分离效果较好。     

丹江镇辣椒红酸汤细菌菌群多样性分析及抗食源性致病菌乳酸菌筛选

以贵州丹江镇传统辣椒红酸汤为研究对象,采用Illumina MiSeq高通量测序技术进行细菌菌群多样性分析,结合微生物纯培养技术和双层平板法从中分离优势乳酸菌,通过分子生物学技术对其进行菌种鉴定,并筛选抗食源性致病菌乳酸菌。结果表明,辣椒红酸汤样品中的优势细菌门为厚壁菌门（Firmicutes）和变形菌门（Proteobacteria）;优势细菌属为乳杆菌属（Lactobacillus）。从辣椒红酸汤样品中共分离得到17株乳酸菌,经鉴定,11株为干酪乳杆菌（Lactobacillus casei）、3株为副干酪乳杆菌（Lactobacillus paracasei）、1株为副干酪乳杆菌亚种（Lactobacillus paracasei subsp.）、1株为植物乳杆菌（Lactobacillus plantarum）、1株为乳酸杆菌（Lactobacillus sp.）,其中4株乳酸菌具有较好的产酸和抑菌性能,且干酪乳杆菌ST7-14的抑菌能力最好,对蜡样芽孢杆菌（Bacillus cereus）ST2-1和阴沟肠杆菌（Enterobacter cloacae）ST2-6的抑菌圈直径分别为37.0 mm和31.5 mm。     

酸菜发酵液中乳酸菌的分离与鉴定

从乳酸发酵的酸菜汁中分离筛选到8株产酸能力较高的乳酸菌,通过形态特征、菌落特征、生理生化特征和API试剂条鉴定,结果表明其中有7株菌为植物乳杆菌(Lactobacillus plantarum),1株菌为短乳杆菌(Lactobacillus brevis)。     

恩施市3种泡辣椒样品中细菌多样性研究

以恩施市3种泡辣椒为研究对象,使用MiSeq高通量测序技术与聚合酶链式反应-变性梯度凝胶电泳(PCR-DGGE)技术相结合的手段对样品中细菌群落的结构进行解析,并采用传统微生物培养方法及分子生物学技术对其中的乳酸菌进行分离和鉴定。结果表明,硬壁菌门(Firmicutes)和变形菌门(Proteobacteria)为泡辣椒中的优势细菌门,其平均相对含量分别为85.70%、12.59%;乳酸杆菌属(Lactobacillus)为优势细菌属,其平均相对含量达67.37%。通过传统微生物培养方法共分离鉴定出14株乳酸菌,其中7株为植物乳杆菌(Lactobacillus plantarum),2株为发酵乳杆菌(Lactobacillus fermentum),3株为屎肠球菌(Enterococcus faecium),2株为香肠乳杆菌(Lactobacillus farciminis)。结果表明,泡辣椒中的优势乳酸菌为植物乳杆菌。     

酸驼乳发酵乳酸菌菌株的筛选及其发酵特性研究

对新疆自然发酵骆驼乳中乳酸菌菌群进行分离鉴定得到五株乳酸菌,其中乳杆菌3株分别为瑞士乳杆菌(Lactobacillus helveticus)、植物乳杆菌(Lactobacillus plantrum)和开菲尔乳杆菌(Lactobacillus kefiri),片球菌2株分别为乳酸片球菌(Pediococcus acidilactici)戊糖片球菌(Pediococcus pentosaceus)。分离鉴定出的五株乳酸菌在培养基中生长良好,其活菌数在培养16 h后能达到109 CFU/m L。将传统酸奶发酵剂接种于骆驼乳中并于42℃条件下培养,发现其在骆驼乳中能较好地产酸,其添加量在0.1%时最适。将筛选到的乳酸菌制备成生产发酵剂与传统酸奶发酵剂复配,得到瑞士乳杆菌组的复配效果最佳,具有最优的产酸效果,在经过6 h发酵后p H值降到4.5左右,酸度达到85oT,且制备的发酵骆驼乳具有最好的感官品质,其感官评分明显高于其他菌株复配进行发酵的骆驼乳产品。因此,可将0.1%传统酸奶发酵剂与筛选到的瑞士乳杆菌制备的生产发酵剂复配应用于酸驼乳发酵。     

清香型白酒酒醅发酵菌株分离鉴定及细菌群落结构分析

采用纯培养技术对清香型白酒酒醅中的乳酸菌和芽孢杆菌进行分离鉴定,同时通过Illumina MiSeq高通量测序技术解析清香型白酒酒醅细菌群落结构。结果表明,所有酒醅样品共分离得到13株乳酸菌,分别鉴定为乳酸片球菌（Pediococcus acidilactici）4株、副干酪乳杆菌（Lactobacillus paracasei）3株、短乳杆菌（Lactobacillus brevis）3株、粪肠球菌（Enterococcus faecium）2株以及希尔氏乳杆菌（Lactobacillus hilgardii）1株。从酒醅中分离得到的17株芽孢杆菌菌株分别鉴定为地衣芽孢杆菌（Bacillus licheniformis）9株、枯草芽孢杆菌（Bacillus subtilis）2株、短小芽胞杆菌（Bacillus pumilus）2株、澳洲芽孢杆菌（Bacillus australimaris）2株、解淀粉芽孢杆菌（Bacillus amyloliquefaciens）1株以及蜡样芽孢杆菌（Bacillus cereus）1株。Illumina MiSeq高通量测序技术结果显示,酒醅中优势菌门分别为厚壁菌门（Firmicutes）（97.96%）、放线菌门（Actinobacteria）（1.24%）和变形菌门（Proteobacteria）（0.76%）;优势细菌属为乳酸杆菌属（Lactobacillus）（97.42%）、栖热嗜油菌属（Thermoleophilum）（1.22%）和假单胞菌属（Pseudomonas）（0.72%）。     

鄂尔多斯地区酸粥细菌多样性分析及乳酸菌的分离鉴定

以采集自内蒙古鄂尔多斯地区的8个酸粥样品为研究对象,利用Illumina MiSeq高通量测序技术,对样品进行细菌菌群结构及多样性研究,分离鉴定其优势菌株。结果表明:8个样品中的细菌主要来自厚壁菌门(Firmicutes)和变形菌门(Proteobacteria),乳酸杆菌属(Lactobacillus)和醋酸杆菌属(Acetobacter)为优势菌属。乳酸杆菌属在各样品中占比最高,为42.63%～97.49%。SZ1、SZ2样品与其他样品的菌群结构差异较大,可能与不同采集时间有关。对上述样品中的乳酸菌进行分离纯化,通过生理生化试验结合分子生物学方法,鉴定获得1株干酪乳杆菌(Lactobacillus casei),1株发酵乳杆菌(Lactobacillus fermentum),2株植物乳杆菌(Lactobacillus plantarum)和4株副干酪乳杆菌(Lactobacillus paracasei)。上述研究结果为酸粥工业化生产提供菌种资源和理论依据。     

广西地区青年人肠道乳酸菌的分离及其发酵酸奶品质的评价

采用传统的可培养方法对广西青年人肠道乳酸菌进行了分离与纯化,通过16S rRNA序列分析对菌株进行了鉴定,并将筛选菌株作为酸奶发酵剂应用。结果表明,分离到的23株乳酸菌中被鉴定为发酵乳杆菌（Lactobacillus fermentum）11株,唾液乳杆菌（Lactobacillus salivarius）6株,格氏乳杆菌（Lactobacillus gasseri）2株,副干酪乳杆菌（Lactobacillus paracasei）1株,融合魏斯氏菌（Weissella confuse）2株和口乳杆菌（Lactobacillus oris）1株。筛选乳酸菌制作的酸奶之间芳香类物质差异并不显著（P＞0.05）,而酸奶样品间酸味、后味A和丰度差异较大。进一步分析表明,副干酪乳杆菌HBUAS54287、唾液乳杆菌HBUAS54223与HBUAS54248、格氏乳杆菌HBUAS54233、发酵乳杆菌HBUAS54238与HBUAS54318乳酸产生能力较强,可进一步筛选用于酸奶复合发酵剂的开发。     

贵州少数民族酸肉、酸鱼中乳酸菌的分离鉴定

采用传统微生物分离方法进行乳酸菌纯种分离,利用16S rRNA序列分析方法进行乳酸菌鉴定,从7个酸肉、酸鱼样品中共分离出14株乳酸菌,有乳杆菌属、环丝菌属、乳球菌属3个属,9个种.从其中鉴定出7株乳酸菌,分别是:植物乳杆菌(Lactobacillus plantarum)、消化乳杆菌(Lactobacillus alimentarius)、清酒乳杆菌(Lactobacillus sakei)、泡菜乳杆菌(Lactobacillus kinchi)、清酒乳杆菌亚种(肉)(Lactobacillus sakei subsp.carnosus)、草乳杆菌(Lactobacillus graminis)、弯曲乳杆菌(Lactobacillus curvatus).     

Biodiversity of lactic acid bacteria isolated from fermented milk products in Xinjiang,China

Fermented dairy products have been produced and consumed for thousands of years in Xinjiang, China. In this study, traditional culture-dependent methods and 16S rRNA gene analyses were performed to analyze the composition of lactic acid bacteria (LAB) from 86 samples of traditional fermented dairy products collected from four regions of Xinjiang. Quantitative polymerase chain reaction (qPCR) was used to quantify Bifidobacterium and Lactobacillus species. The LAB isolates (N = 705) were identified as belonging to seven genera and 26 species or subspecies. The predominant species of all isolates were Lactobacillus (Lb.) delbrueckii subsp. bulgaricus, Lb. fermentum, and Lb. helveticus. The LAB counts of these samples ranged from 5.35 to 10.06 Log CFU/mL. The bacterial counts of seven lactobacilli species and Bifidobacterium ranged from 0.98 ± 0.14 Log CFU/mL (for Lb. sakei from fermented mare milk) to 9.91 ± 0.17 Log CFU/mL (for Lb. helveticus from fermented mare milk). While the microbiota was significantly different between yak and cow milk, there was no significant difference between the Tex and Zhaosu counties. In conclusion, LAB communities in traditional fermented dairy products are complex and differ among local regions within Xinjiang.     

Moulds, yeasts and aerobic plate counts in ginseng supplements

Forty six ginseng supplement samples including Siberian ginseng root, Chinese ginseng herb and root, and American ginseng root and extract were purchased from retail in the Washington, DC area and from Penn Herb Co. (Philadelphia, PA) and tested for mould and yeast (MY) contamination and the presence of aerobic mesophilic bacteria (APC). Results indicated that 100% of the Siberian ginseng samples were contaminated with fungi and bacteria. MY counts ranged from 8.0 x 10(2) to 1.4 x 10(3) cfu/g whereas the APCs were between 2.3 x 10(4) and 1.0 x 10(6) cfu/g. Most common fungi encountered in this commodity were Penicillium spp., Eurotium rubrum, E. chevalieri and Rhizopus spp. Seventy-eight percent of the Chinese ginseng herb samples were contaminated with fungi and 89% with bacteria at levels ranging between <100 and 6.0 x 10(4) and <100 and 1.2 x 10(6) cfu/g, respectively. Moulds commonly isolated were Alternaria alternata, Aspergillus niger, Aspergillus spp., Cladosporium spp., E. chevalieri, Penicillium spp. and Rhizopus spp. Fifty six percent of the Chinese ginseng root samples tested contained fungi (A. niger, Rhizopus spp. and yeasts), and 100% contained bacteria. Fungal counts ranged between <100 and 1.4 x 10(3) cfu/g and APCs were between 3.0 x 10(2) and 6.8 x 10(5) cfu/g. Forty-eight percent of the American ginseng root samples contained moulds and 30% showed bacterial contamination. MY counts were between <100 and 4.3 x 10(5) cfu/g whereas APCs were between <100 and 4.5 x 10(4) cfu/g. A. flavus was isolated from 9% and Penicillium spp. were recovered from 39% of the tested samples. This is the first report of A. flavus contamination in ginseng supplements. No moulds or yeasts were found in ginseng extract, but 50% of these samples contained bacteria at levels ranging between <100 and 1.0 x 10(3) cfu/g.     

Technological characterization of the natural lactic acid bacteria of artisanal Turkish White Pickled cheese

The aim of this study was to characterize the lactic acid bacteria (LAB) isolated from White Pickled cheeses produced with traditional methods; and to improve the quality of cheesemaking with a selection of bacterial cultures from artisanal White cheeses. LAB were isolated and identified from 30 White Pickled cheese samples collected from various cities in Turkey. Also, the numbers of several microbial groups (total aerobic mesophilic bacteria, LAB, enterococci, coliforms, moulds and yeasts) of cheese samples were enumerated. Lactobacilli, lactococci and enterococci were the most abundant microbial groups. The numbers of Enterococcus and Lactobacillus isolates were higher than those of the other LAB. Enterococcus faecalis (24.43%), Enterococcus faecium (17.61%) and Lactobacillus fermentum (19.88%) isolates were the most frequently isolated species. Lactococcus strains showed the highest acidifying activity, followed by Enterococcus and Lactobacillus strains. Proteolytic activity of Enterococcus faecalis strains was higher than that of the other enterococci species, except Enterococcus avium strains. Within lactobacilli strains, the highest mean proteolytic activity was that of Lactobacillus bifermentans, Lactobacillus brevis and Lactobacillus casei strains.     

Spontaneous organic cocoa bean box fermentations in Brazil are characterized by a restricted species diversity of lactic acid bacteria and acetic acid bacteria

Spontaneous organic cocoa bean box fermentations were carried out on two different farms in Brazil. Physical parameters, microbial growth, bacterial species diversity [mainly lactic acid bacteria (LAB) and acetic acid bacteria (AAB)], and metabolite kinetics were monitored, and chocolates were produced from the fermented dry cocoa beans. The main end-products of the catabolism of the pulp substrates (glucose, fructose, and citric acid) by yeasts, LAB, and AAB were ethanol, lactic acid, mannitol, and/or acetic acid. Lactobacillus fermentum and Acetobacter pasteurianus were the predominating bacterial species of the fermentations as revealed through (GTG)₅-PCR fingerprinting of isolates and PCR-DGGE of 16S rRNA gene PCR amplicons of DNA directly extracted from fermentation samples. Fructobacillus pseudoficulneus, Lactobacillus plantarum, and Acetobacter senegalensis were among the prevailing species during the initial phase of the fermentations. Also, three novel LAB species were found. This study emphasized the possible participation of Enterobacteriaceae in the cocoa bean fermentation process. Tatumella ptyseos and Tatumella citrea were the prevailing enterobacterial species in the beginning of the fermentations as revealed by 16S rRNA gene-PCR-DGGE. Finally, it turned out that control over a restricted bacterial species diversity during fermentation through an ideal post-harvest handling of the cocoa beans will allow the production of high-quality cocoa and chocolates produced thereof, independent of the fermentation method or farm.     

小米发糕发酵剂中乳酸菌的筛选及其在小米发糕中的应用

以5种小米品种为研究对象,通过自然发酵法制备小米发糕发酵剂,测定菌落总数、感官评定发糕品质,获得品质差异较大的2种发酵剂,并对其中的乳酸菌进行分离、纯化,通过形态学、生理生化和测序进行鉴定。且研究了乳酸菌对小米发糕含水量、pH、TTA值、糖度和感官品质的影响。结果表明,乳酸菌的计数结果分别为6.48×10~7～8.57×10~9 cfu/g,1号(长农35)制备的小米发糕品质最好,6号(长谷4号)反之。2种发酵剂中鉴定出乳酸菌包括食窦魏斯氏菌(11株)、魏斯氏菌属(18株)和柠檬明串珠菌(4株),其中优势菌为魏斯氏菌属。乳酸菌LA6-40发酵制备的小米发糕含水量39.74%、pH 6.20、TTA值5.3、还原糖含量2.27 g/100 g,感官评分77.1分,色泽金黄、口感细腻、酸甜适中、咬劲适度、弹性良好,是较为适合小米发糕制备的乳酸菌菌株。     

Description of the microflora of sourdoughs by culture-dependent and culture-independent methods

Four types of sourdoughs (L, C, B, Q) from artisanal bakeries in Northern Italy were studied using culture-dependent and culture-independent methods. In all samples, the yeast numbers ranged from 160 to 10⁷ cfu/g, and the numbers of lactic acid bacteria (LAB) ranged from 10³ to 10⁹ cfu/g. The isolated LAB were sequenced, and a similarity was noted between two samples (C, Q), both in terms of the species that were present and in terms of the percentage of isolates. In these two samples, Lactobacillus plantarum accounted for 73% and 89% of the bacteria, and Lactobacillus brevis represented 27% and 11%. In the third sample (B), however, the dominant LAB isolate was Lb. brevis (73%), while Lb. plantarum accounted for only 27%. The fourth sourdough (L) was completely different from the others. In this sample, the most prominent isolate was Weisella cibaria (56%), followed by Lb. plantarum (36%) and Pediococcus pentosaceus (8%). In three out of four samples (L, C and Q), all of the yeasts isolated were identified as Saccharomyces cerevisiae, yet only Candida humilis (90%) and Candida milleri (10%) were isolated in the fourth sample (B). The microbial ecology of the sourdoughs was also examined with direct methods. The results obtained by culture-independent methods and DGGE analysis underline a partial correspondence between the DNA and RNA analysis. These results demonstrate the importance of using a combined analytical approach to explore the microbial communities of sourdoughs.     

On the microbiological profile of traditional Portuguese sourdough

Traditional manufacture of bread from maize has been noted to play important roles from both economic and social standpoints; however, enforcement of increasingly strict hygiene standards requires thorough knowledge of the adventitious microbiota of the departing dough. To this goal, sourdough as well as maize and rye flours from several geographic locations and in two different periods within the agricultural year were assayed for their microbiota in sequential steps of quantification and identification. More than 400 strains were isolated and taxonomic differentiation between them was via Biomerieux API galleries (375 of which were successfully identified) following preliminary biochemical and morphological screening. The dominant groups were yeasts and lactic acid bacteria (LAB). The most frequently isolated yeasts were Saccharomyces cerevisiae and Candida pelliculosa. The most frequently isolated LAB were (heterofermentative) Leuconostoc spp. and (homofermentative) Lactobacillus spp.; L. brevis, L. curvatus, and L. lactis ssp. lactis were the dominant species for the Lactobacillus genera; Lactococcus lactis ssp. lactis for lactococci; Enterococcus casseliflavus, E. durans, and E. faecium for enterococci; and Streptococcus constellantus and S. equinus for streptococci.     

红茶菌中优势微生物的分离鉴定及系统发育分析

采用不同的培养基对红茶菌优势微生物进行了分离,共得到酵母菌8.3×106个/mL,醋酸菌1.4×107个/mL,选取不同的菌落进行纯化后得到2株醋酸菌和4株酵母菌。经过分子生物学鉴定和系统发育树分析后,初步确定AC1为醋酸杆菌Acetobacter senegalensis,AC2为葡糖醋杆菌Gluconacetobactersaccharivorans;Y1为膜璞毕赤酵母Pichia membranifaciens,Y2为毕赤酵母Pichia galeiformis,Y3为异型德克酵母Dekkera anomala,Y4为拜耳接合酵母Zygosaccharo-myces bailii。     

Phenotypic identification and technological properties of lactic acid bacteria isolated from traditionally processed fish products of the Eastern Himalayas

Sukako maacha, gnuchi, sidra and sukuti are traditional smoked and sun-dried fish products of the Eastern Himalayan regions of Nepal and India. A total of 40 samples of sukako maacha (14), gnuchi (6), sidra (10) and sukuti (10) were collected and were analysed for microbial load. Population of lactic acid bacteria (LAB) as well as aerobic mesophilic counts ranged from 4.7-8.3 to 5.1-8.5 log cfu g(-1), respectively. A total of 189 strains of LAB were isolated from sukako maacha, gnuchi, sidra and sukuti samples, out of which 171 strains were cocci and 15 strains, were heterofermentative lactobacilli. LAB were identified on the basis of phenotypic characters including API system as Lactococcus lactis subsp. cremoris, Lactococcus lactis subsp. lactis, Lactococcus plantarum, Leuconostoc mesenteroides, Enterococcus faecium, Enterococcus faecalis, Pediococcus pentosaceus and Weissella confusa. LAB strains produced a wide spectrum of enzymes. Some strains of LAB showed antagonistic properties against pathogenic strains. None of the strains produced biogenic amines in the method applied. This paper is the first report on the microbial composition, mostly lactic acid bacteria, of traditionally processed fish products of Eastern Himalayas.     

Investigation of Microbial Communities of Chinese Sourdoughs Using Culture‐Dependent and DGGE Approaches

Sourdough is typically characterized by the complex microbial communities mainly comprising of yeasts and lactic acid bacteria (LAB). The objective of this study was to explore the microbiota of Chinese traditional sourdoughs collected from different areas of China using culture‐dependent and denaturing gradient gel electrophoresis (DGGE) methods. A total of 131 yeasts, 2 molds, and 106 LAB strains were isolated and identified. Based on the culture‐dependent analysis, the populations of yeasts and LAB were at the level of 10⁵ to 10⁷ and 10⁶ to 10⁷ cfu/g, respectively. Similarly, the results of RT‐qPCR showed that the values of total yeasts and LAB populations were in the range of 10⁶ to 10⁷ and 10⁷ to 10⁸ copies/g, respectively. Using culture‐dependent method, a total of 7 yeasts, 2 molds and 7 LAB species were identified. Results showed that Saccharomyces cerevisiae and Lactobacillus plantarum were the predominant species among the yeasts and LAB microflora. Similarly, using PCR‐DGGE approach, 7 yeasts, 1 mold and 9 LAB species were detected. The yeast, S. cerevisiae, represented the predominant, while the yeast Candida tropicalis represented the subdominant species of the yeast community. Among the LAB community, Lactobacillus sanfranciscensis was the predominant species, while Lactococcus qarvieae, Enterococcus faecium, Lactobacillus delbrueckii and Enterococcus cecorum were among the less dominant species.