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。     

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.     

利用16S rDNA序列及tuf-RFLP鉴定蒙古国发酵乳中的乳酸菌

运用16S rDNA序列分析和tuf-RFLP技术对采于蒙古国扎布汗省的25份发酵乳样中分离出的110株乳酸菌进行鉴定。首先将分离的110株乳酸菌的16S rRNA基因进行扩增,测序并构建系统发育树,初步鉴定为41株嗜热链球菌,40株瑞士乳杆菌,11株德氏乳杆菌保加利亚亚种,2株发酵乳杆菌,1株乳明串珠菌,2株肠膜明串肠膜亚种,1株乳酸乳球乳酸亚种和12株属于干酪族的菌株。由于干酪乳杆菌族的16S rDNA序列差异很小,故采用tuf-RFLP技术对这12株进行了进一步的验证,通过分离菌株与模式菌株tuf-RFLP图谱的比较分析,结果表明这12株菌均为干酪乳杆菌。     

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%)。     

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。     

自然发酵风干肠中乳酸菌的分离与鉴定

以自然发酵风干肠为研究对象,分析了细菌总数和乳酸菌菌数的变化情况,结果表明,乳酸菌为风干肠发酵过程中的优势菌群.通过对风干肠中乳酸菌的分离鉴定,共分离出戊糖片球菌(Pediococcus pentosaceus)、乳酸乳球菌乳酸亚种(Lactococcus lactis subsp lactis)、短乳杆菌(Lactobacillus brevis)、弯曲乳杆菌(Lactobacillus curvatus)和发酵乳杆菌(Lactobacilus fermentum)5株乳酸菌.24h产酸速率测定结果表明,弯曲乳杆菌＞短乳杆菌＞乳酸乳球菌乳酸亚种＞戊糖片球菌＞发酵乳杆菌.     

发酵稀奶油工艺优化及脂肪酸组成分析

采用乳酸乳球菌乳脂亚种、干酪乳杆菌、植物乳杆菌植物亚种混合发酵稀奶油,以模糊数学感官评分和酸度为指标,通过单因素试验和正交试验优化发酵工艺,同时分析稀奶油发酵前后常规理化指标和乳酸菌数,利用气相色谱-质谱联用仪分析稀奶油发酵前后脂肪酸组成的变化。结果表明：稀奶油最佳发酵条件为发酵温度35 ℃、发酵时间10 h、接种量3%、菌种比例为乳酸乳球菌乳脂亚种与干酪乳杆菌、植物乳杆菌植物亚种菌液体积比1∶ 1.5∶ 0.5,所制备的发酵稀奶油感官品质较好,蛋白质含量1.36%、脂肪含量36.54%、pH 4.57、酸度67.05 °T、乳酸菌数2.7×108 CFU/mL;稀奶油发酵前后脂肪酸组成种类不变,共检测出18种脂肪酸,主要以肉豆蔻酸、棕榈酸、硬脂酸和油酸为主,发酵后己酸、辛酸、癸酸含量增加,从而使发酵稀奶油香气更浓郁。     

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。     

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。     

酸马奶中干酪乳杆菌发酵特性的研究

研究了从内蒙古锡林浩特传统发酵酸马奶中分离4株(Lb.caseiZL3-1,Lb.caseiZL3-4,Lb.caseiZhang和Lb.caseiXM2-1)具有潜在益生特性的干酪乳杆菌的发酵特性。结果表明,37℃发酵24h结束后,干酪乳杆菌发酵乳滴定酸度为79.75°T,pH值变化在4.52～4.26之间。Lb.caseiZL3-1,Lb.caseiZL3-4,Lb.caseiZhang和Lb.caseiXM2-1在发酵结束的活菌总数分别为8.11×108,8.53×108,9.61×108和5.30×108mL-1,其中Lb.caseiZhang活菌数为最高。24h发酵结束时,Lb.caseiZL3-1,Lb.caseiZL3-4,Lb.caseiZhang和Lb.caseiXM2-1的黏度分别为0.1830,0.2957,0.1167和0.2497Pa.s。发酵过程中质量分数为12%的TCA可溶性氮无明显增加,4株干酪乳杆菌的蛋白水解力无显著性差异(P>0.05)。     

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%).     

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.     

乳酸菌蛋白降解及产香能力分析

研究了分离自新疆酸奶疙瘩中6株乳酸菌在37℃下蛋白质降解和产香能力。结果表明,6株乳酸菌稳定期活菌数均在108CFU/mL以上,且凝乳细腻,具有良好的组织状态。各菌株发酵性能有差异,干酪乳杆菌、瑞士乳杆菌、乳脂乳球菌3株菌发酵性能较植物乳杆菌、嗜热链球菌、保加利亚乳杆菌发酵性能优,可用于不同风味和功能的发酵乳制品生产。其中,干酪乳杆菌具有良好的蛋白水解力,发酵15h,酪氨酸含量为594.33μg/mL;乳脂乳球菌产香性能好,发酵24h,丁二酮含量为12.32μg/mL、乙醛含量为59.27μg/mL,与其他菌株具有显著差异;瑞士乳杆菌具有强的产酸、产黏特性,发酵24h,酸度达159.76°T,黏度值1 389mPa·s。     

摩洛哥发酵橄榄汁中乳酸菌的分离鉴定及其多样性研究

为了分离、保藏自然发酵食品中乳酸菌资源,丰富自然发酵食品中乳酸菌多样性信息,本文采用纯培养方法和宏基因组16S rRNA基因测序技术对采集自摩洛哥的2份自然发酵橄榄汁中的乳酸菌进行分离鉴定和多样性研究。结果表明:2份样品中共分离鉴定出52株乳酸菌,分属于3个属、4个种,其中乳酸乳球菌（Lactococcus lactis）为摩洛哥卡萨布兰卡地区发酵橄榄汁中的优势菌种,占总分离株的42.31%,同时还分离到植物乳杆菌和肠球菌;利用PacBio SMRT16S rRNA测序技术,将橄榄汁中的细菌归为5个门、40个属和80个种,优势菌种同样为Lactococcus lactis,其次还检测到干酪乳杆菌（Lactobacillus casei）和植物乳杆菌（Lactobacillus plantarum）。     

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。     

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。     

酸马乳发酵过程中乳酸菌与酵母菌生长的相互影响

研究新疆酸马乳中乳酸乳球菌WLB5、干酪乳杆菌MLS5与马克思克鲁维酵母菌WWMJ1间的相互作用。结果表明：在酸马乳发酵过程中,马克思克鲁维酵母菌WWMJ1可以促进干酪乳杆菌MLS5的生长,干酪乳杆菌MLS5对马克思克鲁维酵母菌WWMJ1的生长有抑制作用,乳酸乳球菌WLB5能促进马克思克鲁维酵母菌WWMJ1的生长。乳酸乳球菌WLB5和干酪乳杆菌MLS5混合发酵有助于提高酸马乳中乳酸菌总活菌数。本研究可为酵母菌在发酵乳制品中的应用及开发新型乳制品提供一定参考。     

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.     

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.