辣白菜中乳酸菌的分离鉴定

从沈阳市7 个区25 份朝鲜族家庭制作的传统发酵辣白菜中分离出81 株乳酸菌疑似菌株,初步鉴定34 株为杆菌,47 株为球菌。进一步采用16S rDNA序列分析对81 株菌进行分子鉴定,通过序列分析进行属种鉴定。结果表明：81 株菌均为乳酸菌,分别来自2 个属6 个种,45 株为屎肠球菌,25 株为植物乳杆菌,4 株为干酪乳杆菌,3 株为戊糖乳杆菌,2 株为短乳杆菌,2 株为坚强肠球菌。研究结果为我国东北辣白菜中乳酸菌作进一步研究奠定了基础。     

内蒙古腌制沙葱中乳酸菌分离鉴定

以采集自内蒙古腌制沙葱为研究对象,通过微生物纯培养方法分离培养其中乳酸菌。应用16S r RNA基因序列分析和系统发育关系研究手段,对分离菌株进行鉴定,并与其他地区不同种类发酵蔬菜中分离得到的乳酸菌进行比较。结果表明:共分离得到6株乳酸菌,包括2株干酪乳杆菌(Lactobacillus casei),2株乳酸乳球菌乳酸亚种(Lactococcus lactis subsp lactis)、1株肠膜明串珠肠膜亚种(Leuconostoc mesenteroides subsp.mesenteroides)和1株Lactobacillus diolivorans。相比于其他地区发酵蔬菜中分离所得的乳酸菌,内蒙古腌制沙葱样品分离得到的乳酸菌数量虽少,但也具有特有菌种。     

泡菜发酵乳酸菌的分离鉴定及耐药性分析

对吉林地区朝鲜族自制泡菜中的发酵乳酸菌进行分离鉴定,并对菌株耐药情况进行分析,以期为泡菜发酵菌的风险评估奠定基础。采集吉林省多个不同地区的泡菜制品,通过MRS培养基分离,16S rDNA测序,分析其乳酸菌种类及数量,同时采用平板琼脂稀释法进一步检测了分离菌对10 种临床常用抗生素的药物敏感性。结果表明,从15 份不同厂家泡菜中共分离得到34 株乳酸菌,分别为植物乳杆菌12 株,短乳杆菌5 株,鼠李糖乳杆菌3 株,干酪乳杆菌2 株,清酒杆菌2 株,肠膜明串珠菌2 株,嗜热链球菌2 株,食窦魏斯氏乳杆菌1 株,弯曲乳杆菌1 株,棒状乳杆菌1 株,嗜酸乳杆菌1 株,坚强肠球菌1 株,Lactobacillus namurensis 1 株。药敏实验结果表明,所有菌株对氨苄西林和氯霉素敏感,对其他抗生素均有不同程度的耐药性,其中对环丙沙星耐药率最高。     

传统发酵酸牛奶中乳酸菌多态性分析

以从内蒙古呼伦贝尔市牧区采集的1份传统发酵酸牛奶样品为研究对象,对其进行乳酸菌的分离鉴定。通过传统纯培养法分离出17株菌,并对17株菌进行16SrDNA序列分析、多位点pheS序列分析和生理生化鉴定,鉴定的结果为11株乳酸乳球菌乳酸亚种、1株格式乳球菌、1株粪肠球菌、2株植物乳杆菌植物亚种及2株弯曲乳杆菌。乳酸乳球菌乳酸亚种为优势菌(占总分离菌株的64.7%)。     

水牛乳中可培养乳酸菌多样性分析

采用传统分离培养方法,从三品杂交生水牛奶混合样品中,分离出105株乳酸菌,通过形态、生理生化、API细菌鉴定系统及16S rDNA基因序列分析方法对各菌株属种进行鉴定。16S rRNA序列分析结果显示,105株菌共分为5个属8个种,呈现较为丰富的乳酸菌多样性,具体数量分布为乳酸乳球菌21株,植物乳杆菌19株,格氏乳球菌17株,乳明串珠菌13株,食窦魏斯氏菌11株,肠膜明串珠菌8株,类肠膜魏斯氏菌6株,嗜热链球菌5株,糊精乳杆菌5株。由此可知,水牛乳中可培养乳酸菌优势菌群的主次关系为：乳酸乳球菌（Lactococcus lactis）＞植物乳杆菌（Lactobacillus plantaru）＞格氏乳球菌（Lactococcus garvieae）＞乳明串珠菌（Leuconostoc lactis）＞食窦魏斯氏菌（Weissella cibaria）,此为后续开发水牛乳中优势乳酸菌资源提供了良好的理论基础。     

开菲尔(Kefir)酸牛乳酒中乳酸菌分离及发酵性能测定

对自制的开菲尔酸牛乳酒进行分离得到16株乳酸菌,通过显微镜观察及生理生化特性研究,结果为肠膜明串珠菌乳脂亚种两株,乳酸乳球菌乳酸亚种2株,乳酸乳球菌乳脂亚种2株,粪肠球菌1株,瑞士乳杆菌3株,德氏乳杆菌保加利亚亚种2株,嗜酸乳杆菌4株;经发酵性能测定,筛选出2株乳酸球菌LC2、LC6和3株乳酸杆菌LB3、LB4、LB8发酵活力较高、发酵乳组织状态及风味较好,可作为Kefir酸牛乳酒纯培养发酵剂乳酸菌的备选菌株.     

伊犁地区乳品中乳酸菌的分离及鉴定

从伊犁地区牧民家庭采集的乳品中分离得到10株乳酸菌,经过对其生物学特性的鉴定,有干酪乳杆菌假植物亚种(L.casei subsp.Plantaman)4株、鸡肠球菌(E.gallins.rum)1株、屎肠球菌(E.faecium)1株、乳酸乳球菌乳酸亚种(L.lactis subsp.cremoris)2株、肠膜明串珠菌肠膜亚种(Lc.Mesenteroides subsp.Mesenteroides)2株。通过研究发现,该鉴定菌株的生物学特性基本符合各属和种的鉴定标准,均属于中温性乳酸菌。     

四川牦牛奶和曲拉中九株乳酸菌的分子鉴定

为准确鉴定分离自我国四川鲜牦牛奶和曲拉中9株乳酸菌到种水平,作者运用16S rDNA序列分析、recA基因特异扩增和hsp60-RFLP等多种分子技术对分离自我国四川地区鲜牦牛奶和曲拉中的9株乳酸菌进行分类鉴定。结果证实,16S rDNA序列分析法可将9株乳酸菌初步归类为植物乳杆菌群(4株),肠膜明串珠菌(4株),瑞士乳杆菌(1株)。由于16S rDNA序列分析法不能区分植物乳杆菌和戊糖乳杆菌,为了进一步鉴定植物乳杆菌群中的4株菌,继续采用recA基因特异扩增和hsp60-RFLP技术对其细分,结果表明recA基因特异扩增和hsp60-RFLP的方法均能很好地把植物乳杆菌群中的4株菌鉴定到种水平,且均为植物乳杆菌。     

新疆传统乳制品中乳酸菌的分离鉴定

以5种新疆当地传统乳制品为原料进行乳酸菌的分离和鉴定，共分离出36株凝乳状态较好的乳酸菌，对其中16株产酸速率较快的菌株利用部分生理生化和糖发酵试验进行了鉴定。结果表明，9株为乳酸乳球菌乳酸亚种，1株为干酪乳杆菌假植物亚种，2株未知，需进二步鉴定，其余4株杆菌为乳酸乳杆菌。     

新疆酸马奶中乳酸菌的多态性分析及发酵性能研究

以新疆牧民传统家庭自制酸马奶样品为研究对象,考察乳酸菌的多态性及筛选优良性状的乳酸菌菌株。通过16S r RNA基因序列分析和生理生化试验等方法对分离出的菌株进行鉴定,并进行发酵性能测试。结果表明,本实验共分离出19株菌株,包括乳酸乳球菌乳酸亚种(Lactococcus lactis subsp.lactis)(8株)、粪肠球菌(Enterococcus faecalis)(2株)、屎肠球菌(Enterococcus faecium)(2株)、嗜热链球菌(Streptococcus thermophilus)(1株)、干酪乳杆菌(Lactobacillus casei)(3株)、植物乳杆菌(Lactobacillus plantarum)(2株)和徳氏乳杆菌乳酸亚种(Lactobacillus delbrueckii subsp.Lactis)(1株)。其中,干酪乳杆菌JDB1.1505是一株产酸和产黏性能都比较突出的乳酸菌,发酵脱脂乳的滴定酸度达到了130.1°T,黏度为1420.1m Pa·s,具有良好的乳品发酵应用潜能。     

Characterization of certain bacterial strains for potential use as starter or probiotic cultures in dairy products

The present work was aimed at characterizing 12 strains of lactic acid bacteria (LAB) to obtain improved potential starter or probiotic cultures that could be used for making dairy products from ewe's milk and cow's milk. Eight strains with antimicrobial properties, isolated from ewe's milk and from cheese made from ewe's and/or cow's milk, were studied. They were identified as Enterococcus faecalis (five strains), Lactococcus lactis subsp. cremoris, Leuconostoc mesenteroides, and Lactobacillus paracasei subsp. paracasei (one strain of each species). Additionally, four strains were obtained from the American Type Culture Collection: Lactobacillus casei 393 (isolated from cheese), L. lactis subsp. lactis 11454 (origin nonspecified and a producer of nisin), and two strains isolated from human feces (L. paracasei subsp. paracasei 27092 and Lactobacillus rhamnosus 53103, antibacterial agent producer). All E. faecalis strains showed at least one virulence factor (either hemolysin or gelatinase), which emphasizes the importance of these studies in this species. Both L. lactis strains and most Lactobacillus spp. were good acidifiers in ewe's milk and cow's milk at 30°C. High β-galactosidase activity, as well as aminopeptidase activities that favor the development of desirable flavors in cheese, were detected in all Lactobacillus spp. strains. Furthermore, L. rhamnosus ATCC 53103 showed α-fucosidase activity (thought to help colonization of the intestine) and lack of α-glucosidase activity (a trait considered positive for diabetic and obese humans). This last enzymatic activity was also lacking in L. lactis ATCC 11454. L. mesenteroides was the only strain D(2)-lactic acid producer. The selection of any particular strain for probiotic or dairy cultures should be performed according to the technological and/or functional abilities needed.     

The microbiology of South African traditional fermented milks

A total of 15 samples of traditional fermented milk were collected from individual households in South Africa and Namibia. Lactic acid bacteria dominated the microflora of these samples, especially the genera Leuconostoc, Lactococcus and Lactobacillus. Other groups identified included pyogenic streptococci and enterococci. The dominant lactococci species was Lactococcus lactis subsp. lactis. Eighty-three percent of the leuconostoc isolates were identified as Leuconostoc mesenteroides subsp. dextranicum. Other species identified included Leuconostoc citreum, Leuconostoc lactis, Lactobacillus delbrueckii subsp. lactis and Lactobacillus plantarum.     

内蒙古酸马奶中乳酸菌多样性的研究

采用16S rRNA基因全序列测定和聚类分析技术,对酸马奶中的乳酸菌进行了准确鉴定并构建了乳酸菌的系统发育树.然后对乳酸菌菌群进行了多样性分析,结果显示,酸马奶中的优势乳酸菌分别为:Lactobacillus plantarum(10%),Lactobacillus brevis(8%),Lactobacillus casei(7.8%),Enterococcus faecium(17%),Enterococcus faecalis(14%),Lactococcuslactis(19%),Lactobacillus acidlophilus(5%),Lactobacillus paracasei(2%),Lactobacillus delbrueckii subsp.bulgaricus(4%),Lactobacillus helveticus(4%),Enterococcus durans(4%),Leuconostoc mesenteroides (4%),Leuconostoc garlicum(1%),Streptococcus thermophilus(1%).     

Screening of some potentially probiotic lactic acid bacteria for their ability to synthesis conjugated linoleic acid

Strains of potentially probiotic lactobacilli, propionibacteria, leuconostoc, lactococcus, enterococcus, and pediococcus, were tested for their ability to convert linoleic acid to conjugated linoleic acid (CLA). Growth and CLA production were followed during incubation for 48 h in reconstituted skim milk containing 0.2% lipolysed sesame oil. Lactococcus lactis subsp. lactis biovar diacetylactis and Leuconostoc mesenteroides subsp. mesenteroides gave the highest CLA production. Also, the effect of lipolysed oil concentration on the growth and CLA production of six strains were studied in medium containing 0.0–1% lipolysed oil. Leuconostoc mesenteroides subsp. mesenteroides and Lac. lactis subsp. lactis biovar diacetylactis gave maximum dienes in medium containing 0.6% and 0.8% lipolysed oil respectively.     

盐渍藠头发酵过程中乳酸菌的分离及特性研究

对盐渍藠头发酵过程中不同时期的乳酸菌进行了分离、鉴定及特性研究,从中分离出9种菌株。通过菌落形态、培养特征和生化试验等鉴定表明,这9种菌株分别为植物乳球菌、发酵乳杆菌、短乳杆菌、菊糖芽孢杆菌、乳酸链球菌、肠膜明串珠菌葡聚糖亚种、植物乳杆菌、皱膜假丝酵母、膜醭毕赤氏酵母菌。并观察了发酵过程中各个时期的主导菌相,最后得出短乳杆菌、发酵乳杆菌可作为盐渍藠头发酵过程中人工接种的试验菌株。     

Characterization of the lactic acid bacteria in ewe's milk and cheese from northwest Argentina

Indigenous lactic acid bacteria in ewe's milk and artisanal cheese were studied in four samples of fresh raw milk and four 1-month-old cheeses from the provinces of northwest Argentina. Mean growth counts on M17, MRS, and MSE agar media did not show significant differences (P < 0.05) in raw milk and cheeses. Isolates of lactic acid bacteria from milk were identified as Enterococcus (48%), lactococci (14%), leuconostocs (8%), and lactobacilli (30%). All lactococci were identified as Lactococcus lactis (subsp. lactis and subsp. cremoris). Lactobacilli were identified as Lactobacillus plantarum (92%) and Lactobacillus acidophilus (8%). Enterococci (59%) and lactobacilli (41%) were isolated from cheeses. L. plantarum (93%), L. acidophilus (5%), and Lactobacillus casei (2%) were most frequently isolated. L. lactis subsp. lactis biovar diacetylactis strains were considered as fast acid producers. L. lactis subsp. cremoris strains were slow acid producers. L. plantarum and L. casei strains identified from the cheeses showed slow acid production. The majority of the lactobacilli and Lactococcus lactis strains utilized citrate and produced diacetyl and acetoin in milk. Enzyme activities (API-ZYM tests) of lactococci were low, but activities of L. plantarum strains were considerably higher. The predominance of L. plantarum in artisanal cheese is probably important in the ripening of these cheeses due to their physiological and biochemical characteristics.     

新疆哈萨克族传统发酵驼乳中乳酸菌的分离鉴定

分别从新疆玛纳斯、乌兰巴依、南山、水西沟采集的4份酸驼乳中,分离得到乳酸菌22株。采用传统形态学、生理生化特性方法对乳酸菌进行鉴定,鉴定结果为Lactobacillus16株(72.72%),Lactococcus 3株(13.63%),Enterococcus 2株(9.10%),Streptococcus 1株(4.55%),优势杆菌为Lactobacillus helveticus(18.18%),优势球菌为Lactococcus lactis subsp.lactis(13.63%)。利用16S rDNA序列同源性分析和系统发育树分析对MLS1进行了分子鉴定,鉴定结果为菌株MLS1与Lactobacillus rhamnosus的同源性达到98.1%,与传统生理生化鉴定结果一致,表明了16S rDNA序列分析应用在乳酸菌鉴定上的准确性。     

Phenotypic and genotypic identification of lactic acid bacteria isolated from ethnic fermented bamboo tender shoots of North East India

Mesu, soidon, soibum and soijim are ethnic fermented bamboo tender shoot products prepared by the people in North East India. Microbiological analysis of mesu, soidon, soibum and soijim showed the population dominated by lactic acid bacteria (LAB) ranging up to 10(8) cfu g(-1). The phenotypic characterisation of predominant LAB isolated from the fermented bamboo shoot products was based on general morphology, physiological tests, API and Biolog systems. The genotypic characterisation of LAB was based on RAPD-PCR, rep PCR, species-specific PCR techniques, 16S rRNA gene sequencing and DNA-DNA hybridisation. Predominant functional LAB strains associated with the fermented bamboo shoot products were identified as Lactobacillus brevis, Lb. plantarum, Lb. curvatus, Pediococcus pentosaceus, Leuconostoc mesenteroides subsp. mesenteroides, Leuc. fallax, Leuc. lactis, Leuc. citreum and Enterococcus durans.     

Isolation of halotolerant Lactococcus lactis subsp. lactis from intestinal tract of coastal fish

We isolated lactic acid bacteria from the intestinal tract of the pufferfish Takifugu niphobles caught in Shimoda, Shizuoka, Japan by using MRS broth prepared with 50% seawater. Additional screening was carried out using phenotypic tests such as Gram staining, cell morphology, catalase, oxidase and fermentation of glucose. Subsequently 227 isolates screened by the phenotypic tests were subjected to species-specific PCR for Lactococcus lactis, resulting in four positive isolates. The 16S rRNA gene sequences from three isolates were highly similar to that of L. lactis subsp. lactis (DNA database accession number M58837), while that of one isolate was identical to that of Leuconostoc mesenteroides (AB023246). These isolates were characterized by API 50 CH for carbohydrate fermentation and other phenotypic criteria for salt tolerance, and the characteristics were compared with those of L. lactis subsp. lactis from a cheese starter culture. The carbohydrate fermentation profiles of these isolates were characteristic of L. lactis subsp. lactis strains, whereas the tolerance of these isolates to salt was higher than that of L. lactis subsp. lactis from the cheese starter culture: the new L. lactis isolates showed high salt tolerance in MRS-agar plates containing 200% seawater or 6% sodium chloride. This is the first report of the isolation of halotolerant strains of L. lactis subsp. lactis from a marine environment.     

Rep-PCR characterization and biochemical selection of lactic acid bacteria isolated from the Delta area of Egypt

Samples of raw milk and traditional dairy products were collected from different rural areas in the Delta region. 170 isolates from these products were identified using repetitive genomic element-PCR (Rep-PCR) fingerprinting. The identified isolates were tested for efficiency of biomass production and separation, acidifying activity, autolytic and aminopeptidase properties, antagonistic activities and exopolysaccharide production. The obtained results revealed that the Lactobacillus delbrueckii subsp. lactis, Lactobacillus fermentum, Enterococcus faecium Lactobacillus delbrueckii subsp. bulgaricus, Lactobacillus paracasei subsp. paracasei, Lactobacillus plantarum and Lactococcus lactis subsp. lactis were the predominant species in Egyptian dairy products. Two percent of Lactococcus, 10% of Lactobacillus and 1% of Enterococcus isolates showed fast acidifying activity. Aminopeptidase and autolytic properties were generally higher for most Lactobacillus strains when compared to other strains. Among these species, lactobacillus paracasei subsp. paracasei was the highest in Aminopeptidase activity and autolytic properties. Antagonistic activity was detected in 40% of Lactococcus, 70% of Lactobacillus and 50% of Enterococcus isolates. Some isolates produced exopolysaccharides in milk and dairy products.