北方中式香肠中片球菌的分离筛选与鉴定

本研究对北方中式香肠中的片球菌进行了分离、纯化、筛选及鉴定。以开发优良发酵剂为目的,筛选鉴定出5株片球菌(R1,R2,R4,R5,R10)。参照《伯杰氏细菌手册》,初步鉴定R1为乳酸片球菌(Pediococcus acidilactici);R4为戊糖片球菌(Pediococcus xylosus);R2、R5、R10为糊精片球菌(Pediococcus dextrinicus)。     

科尔沁地区传统发酵奶豆腐中乳酸菌的鉴定

从科尔沁地区采集到5份传统发酵制作的奶豆腐样中分离出12株供试菌株,将分离的菌株的16S rDNA进行PCR扩增、序列分析并构建系统发育树。结果表明,12株菌株都属于乳酸菌(Lactic Acid Bacteria),其中6株乳杆菌(Lactobacillus),分别是植物乳杆菌(Lactobacillus plantarum)4株、干酪乳杆菌(Lactobacillus casei)1株、戊糖乳杆菌(Lactobacillus pentosus)1株;6株乳球菌(Lactococcus)分别是乳糖片球菌(Pediococcus acidilactici)5株和戊糖片球菌(Pediococcus pentosaceus)1株。鉴定结果与生理生化实验结果一致,且以乳酸片球菌和植物乳杆菌为优势菌群。     

哈萨克斯坦传统发酵乳制品中乳酸菌的多样性

为了阐明哈萨克斯坦传统发酵乳制品中乳酸菌生物多样性,采用传统纯培养方法对采集的5份传统发酵乳制品中的乳酸菌进行分离纯化,运用16S rRNA基因序列分析方法和系统发育树研究进行属种鉴定。结果表明,从5份传统乳制品中分离鉴定了49株乳酸菌分属于4个属8个种或亚种,乳杆菌属(Lactobacillus)44株,片球菌属(Pediococcus)1株、肠球菌属(Enterococcus)3株,链球菌属(Streptococcus)1株。其中乳杆菌属、片球菌属、肠球菌属、链球菌属是哈萨克斯坦地区传统发酵乳制品中的主要乳酸菌,其中Pediococcus pentosaceus为优势菌种,占总分离株的22%。     

自然发酵腐乳中细菌多样性评价

以腐乳为研究对象,利用变性梯度凝胶电泳(polymerase chain reaction-denaturing gradient gel electrophoresis,PCR-DGGE)技术与Miseq高通量测序技术相结合的手段解析及评价细菌多样性,同时利用传统纯培养的方法对乳酸菌进行分离、纯化与鉴定。结果显示:腐乳中主要微生物为变形菌门(Proteobacteria,80.45%),其中绿脓杆菌属、不动杆菌属、鞘氨醇杆菌属、布丘氏菌属和草螺菌属细菌为优势细菌属。同时通过PCR-DGGE和纯培养发现腐乳中鉴定出7株乳酸菌,其中2株为戊糖片球菌(Pediococcus pentosaceus),1株为乳酸片球菌(Pediococcus acidilactici),4株为屎肠球菌(Enterococcus faecium)。由此可知腐乳中蕴含着丰富的微生物资源,同时屎肠球菌(Enterococcus faecium)为优势乳酸菌。     

新疆酸马奶中乳酸菌的乙醇耐受性及蛋白酶性质研究

通过对新疆酸马奶中乳酸菌以传统方式分离鉴定后,筛选得到不同种属菌株,并进一步对其乙醇耐受性及蛋白酶活性差别进行研究。结果表明:在分离的21株菌株中,其不同种属的5株菌株在不同浓度乙醇胁迫12 h后,在耐胁迫能力上,由高到低分别为发酵乳杆菌(Lactobacillus fermentum)、戊糖片球菌(Pediococcus pentosaceus)、植物乳杆菌(Lactobacillus plantarum)、屎肠球菌(Enterococcus faecium)、乳酸片球菌(Pediococcus acidilactici),其中最高能够耐受浓度为13%的乙醇胁迫。对蛋白酶水解能力的测定结果表明,菌株均能产生蛋白酶,其中乳酸片球菌(Pediococcus acidilactici)的水解圈直径最大,为13.1 mm,其菌株自溶度为36.4%。菌株的乙醇耐受性与其蛋白酶水解能力间无显著关联性。     

俄罗斯卡尔梅克共和国发酵蔬菜中细菌多样性研究

通过纯培养的方法结合16S rRNA测序技术对采集自俄罗斯卡尔梅克共和国埃利斯塔市郊的2份发酵蔬菜样品中的乳酸菌进行了分离、鉴定,并构建了系统发育树。经过鉴定,共从2份样品中获得了19株乳酸菌,分属于Lactobacillus(14株)、Pediococcus(3株)和Leuconostoc(2株),其中包括7株Lactobacillus plantarum;1株Lactobacillus brevis;2株Lactobacillus delbrueckii;1株Lactobacillus helveticus;1株Lactobacillus kefiranofaciens;2株Lactobacillus kefiri;1株Leuconostoc lactis;1株Leuconostoc mesenteroides;2株Pediococcus ethanolidurans;1株Pediococcus pentosaceus。此外,该研究以细菌16S rRNA的V1-V3区为靶序列,采用454焦磷酸测序技术从宏基因组角度对2份样品中细菌的丰度和多样性进行了分析,分别从2份样品中获得了10869和12204条高质量序列。经过与RDP(Ribosomal Database)数据库比对,发现隶属于硬壁菌门(Firmicutes)的乳杆菌属(Lactobacillus)和乳球菌属(Lactococcus)分别占到样品中细菌总数的91.66%和3.81%,成为绝对优势菌属。此外,还鉴定到了弧菌属(Vibrio)、片球菌属(Pediococcus)、肠球菌属(Enterococcus)、克鲁维菌属(Kluyvera)等。     

新疆阿克苏地区手工酸乳中发酵菌株的筛选及其发酵性能研究

具有良好发酵性能的乳酸菌菌株是制备发酵剂的关键因素,而发酵剂是发酵乳品质的决定因素之一,因此,筛选优良发酵性能的菌株对于制备发酵剂至关重要。本研究从新疆阿克苏的三份手工酸奶样品中分离出四株经传代接种后,仍能明显凝乳且性能稳定的菌株,经16S rRNA基因测序结合形态生理鉴定为2株干酪乳杆菌(Lactobacillus casei)q8-1与q28-2,1株副干酪乳杆菌(Lactobacillus paracasei)R22-2和1株乳酸片球菌(Pediococcus acidilactici)q4-1。对分离出的这四株菌与实验室前期筛选出具有凝乳稳定性的戊糖片球菌(Pediococcus pentosaceus)K5-2,保加利亚乳杆菌(Lactobacillus bulgaricus)7-1,嗜热链球菌(Streptococcus thermophilus)A-2在乳品中单菌的生长能力、产酸性能、后酸化性能、贮藏过程中的活菌数、感官评定、质构性能以及产香能力进行测定。结果表明,Lactobacillus bulgaricus 7-1发酵性能最佳,其凝乳时间与达到发酵终点时间分别为8与...     

新疆传统乳品中乳酸菌的抗氧化能力

实验用菌为从新疆传统乳制品酸奶和干酪中分离出的7株乳酸菌,分别是乳酸片球菌(Pediococcus acidilactici)1株、植物乳杆菌(Lactobacillus plantarum)3株、耐久肠球菌(Enterococcus durans)1株、魏斯氏菌(Weissella cibaria)1株和面包乳杆菌(Lactobacillus panis)1株。对其清除DPPH自由基、超氧阴离子自由基、羟自由基、还原能力以及亚铁离子螯合能力进行了研究。结果表明:7株乳酸菌具有不同的抗氧化能力,其中植物乳杆菌亚铁离子螯合能力最强,乳酸片球菌超氧阴离子自由基清除能力相对较高,魏斯氏菌的DPPH自由基清除能力较强,面包乳杆菌的羟自由基清除能力和还原能力最强。     

发酵香肠中分离纯化的三株乳酸菌产酸特性研究

为了研究从发酵香肠中分离纯化的3株乳酸菌粪肠球菌(Enterococcus faecalis)、戊糖片球菌(Pediococcus pentosaceus)和肠膜明串珠菌(Leuconostoc mesenteroides)的产酸性能,对这3株菌在不同pH、温度、NaCl、NaNO2条件下的生长情况及产酸情况进行了测定。研究结果显示:这3株菌中,肠膜明串珠菌和戊糖片球菌的生长特性较好;粪肠球菌的生长特性虽不如肠膜明串珠菌和戊糖片球菌,但产酸能力最好,戊糖片球菌耐盐性最好、肠膜明串珠菌耐亚硝酸盐的特性最好;在不同温度和pH条件的测试中,肠膜明串珠菌的生长能力最好,粪肠球菌次之。这3株乳酸菌在发酵肉制品中均产生乳酸。总之,这3株菌均具有用于发酵制备乳酸的能力。     

耐胃液乳酸菌的筛选、鉴定与驯化

利用本实验室分离保存的乳酸菌菌种17株,经过耐胃液实验筛选,得到耐胃液能力较强、生长良好的乳酸菌菌株5株,选取4株菌株利用API乳酸菌生化系统和16S rDNA分析鉴定,并进行耐胃液驯化选育.结果表明,鉴定的4株乳酸菌中2株(编号:BR1-2和R8)为副千酪乳杆菌(Lactobacillus paracasei),1株(编号:BR3-2)为屎肠球菌(Enterococcus faecium),1株(编号:BR2-2)为乳酸片球菌(Pediococcus acidilactici);驯化后各菌株耐胃液能力均有不同程度的提高,其中BR1-2经人工胃液处理存活率提高52.2%;其他三株菌株的存活率也均提高20%以上.     

西藏曲拉和发酵乳中抗氧化和益生特性乳酸菌的筛选及鉴定

以抗过氧化氢、清除自由基为抗氧化指标,耐酸、耐胆盐为益生特性指标,对采集自西藏的自然发酵曲拉和发酵乳中乳酸菌进行了分离、筛选和鉴定。结果表明:从9份样品中分得的62株菌有23株对0.3%过氧化氢具备耐受性,其中4-C、5-D、5-E、9-E对DPPH·和·OH清除率最高分别为86.97%±0.11%、27.62%±0.28%;经鉴定5-D、5-E、9-E、4-C分别为Lactobacillus delbrueckii subsp. Jakobsenii、Lactobacillus delbrueckii subsp. Jakobsenii、Lactobacillus gasseri、Pediococcus pentosaceus;此外,菌株5-D、5-E对酸碱和0.3%胆盐均有较好的耐受能力,具备抗氧化和益生特性,有较大潜力应用于天然抗氧化剂的研究与开发,同时也丰富了西藏地区传统牦牛乳制品中乳酸菌资源库的挖掘工作。     

广西生榨米粉中益生乳酸菌的筛选及鉴定

通过革兰氏染色、过氧化氢酶试验、溶血性试验、耐酸、耐胆盐试验及体外抗氧化能力测定从广西本地传统发酵食品生榨米粉中筛选优良益生乳酸菌，对其生长情况及产酸性能进行测定，并通过分子生物学技术对其进行鉴定。结果表明，共分离得到146株γ-溶血乳酸菌，其中22株乳酸菌对pH 2.0和0.3%胆盐均具有良好耐受性，且乳酸菌PM20、PM22、FD13及PM44的综合体外抗氧化能力较好。4株菌株的生长及产酸趋势一致，其中菌株PM44的生长速度和产酸能力最强。经鉴定菌株PM20、PM22、FD13均为发酵乳杆菌（Lactobacillus fermentum），菌株PM44为乳酸片球菌（Pediococcus acidilactici）。     

In vitro testing of commercial and potential probiotic lactic acid bacteria

Probiotics are defined as live microorganisms which when administered in adequate amounts confer a health benefit on the host. The objective of this study was to investigate the diversity of selected commercial and potential probiotic lactic acid bacteria using common in vitro screening assays such as transit tolerance in the upper human gastrointestinal tract, adhesion capacity to human intestinal cell lines and effect on epithelial barrier function. The selected bacteria include strains of Lactobacillus plantarum, Lactobacillus pentosus, Lactobacillus farciminis, Lactobacillus sakei, Lactobacillus gasseri, Lactobacillus rhamnosus, Lactobacillus reuteri and Pediococcus pentosaceus. Viable counts after simulated gastric transit tolerance showed that L. reuteri strains and P. pentosaceus tolerate gastric juice well, with no reduction of viability, whereas L. pentosus, L. farciminis and L. sakei strains lost viability over 180min. All strains tested tolerate the simulated small intestinal juice well. The bacterial adhesion capacity to human intestinal cells revealed major species and strain differences. Overall, L. plantarum MF1298 and three L. reuteri strains had a significant higher adhesion capacity compared to the other strains tested. All strains, both living and UV-inactivated, had little effect on the epithelial barrier function. However, living L. reuteri strains revealed a tendency to increase the transepithelial electrical resistance (TER) from 6 to 24h. This work demonstrates the diversity of 18 potential probiotic bacteria, with major species and strain specific effects in the in vitro screening assays applied. Overall, L. reuteri strains reveal some interesting characteristics compared to the other strains investigated.     

产胞外多糖乳酸菌的筛选及抗氧化特性研究

以分离自贵州侗族、苗族传统发酵食品的36株乳酸菌为受试菌,筛选出8株高产胞外多糖（膜截留分子质量为8 000~14 000 u）的乳酸菌,分别为SR2-1（Pediococcus sp. F3S1）、SR2-2（Pediococcus pentosaceus NGRI 0304）、SR3-2（Pediococcus pentosaceus LB-WC）、SR8（Lactobacillus kimchi）、SR10-2（Pediococcus sp. 22-4）、SR12-1（Lactobacillus graminis）、H1（Staphylococcus sp. 3034O2）和XS2（Pediococcus pentosaceus GS17）,并对其胞外多糖进行体外抗氧化特性研究。结果显示,8株乳酸菌的胞外多糖均具有抗氧化活性,其中胞外多糖质量浓度为30 μg/mL时,乳酸菌SR2-2、SR8和SR12-1的胞外多糖对Fe2+的清除率分别为15.55%、12.41%、53.21%;胞外多糖质量浓度为40 μg/mL时,乳酸菌SR2-2、SR8和SR12-1的胞外多糖对1,1-二苯基-2-三硝基苯肼（DPPH·）和NO2-的清除率分别达9.69%、11.93%、8.93%及5.73%、7.82%、3.82%。这三株乳酸菌显示出一定的抗氧化活性。     

Dry sausage fermented by Lactobacillus rhamnosus strains

The ability of three probiotic Lactobacillus rhamnosus strains GG, E-97800 and LC-705 and one commercial Pediococcus pentosaceus starter strain (control) to produce dry sausage was studied. During the fermentation process the numbers of inoculated lactic acid bacteria increased from approx. 7 log10 to 8-9 log10 cfu/g and the pH values decreased from 5.6 to 4.9-5.0. The sensory test indicated that the dry sausages fermented by L. rhamnosus LC-705 were inferior to the control sausages. The presence of inoculated experimental strains as predominant organisms in the dry sausages was recognised on the basis of their genetic fingerprints by ribotyping. The concentrations of biogenic amines remained low during the ripening process. These results indicated that the studied Lactobacillus rhamnosus strains, especially strains GG and E-97800, are suitable for use as probiotic starter cultures in fermenting dry sausage.     

发酵酸菜来源乳酸菌的益生特性及其在发酵乳中的应用

通过pH值、胆盐耐受性实验从发酵酸菜中筛选性能优良的益生乳酸菌株,经16S rRNA序列分析鉴定得4 株植物乳杆菌A44、B51、B54、C53和2 株戊糖乳杆菌A16、B72。经疏水、黏附、自凝聚和溶血能力实验评价6 株乳酸菌的益生特性,其中植物乳杆菌A44对氯仿和二甲苯的疏水性均大于80%,对Caco-2细胞的黏附率为13.57%,放置5 h的自凝聚率超过60%,与其他菌株相比具有更好的益生特性且无溶血活性。因此选用植物乳杆菌A44进一步研究其在发酵乳中的功能特性,结果表明：植物乳杆菌A44作为辅助发酵剂添加后对4 ℃贮藏7 d期间发酵乳pH值、滴定酸度和持水性均无显著影响（P＞0.05）,但是可以显著提高发酵乳的活菌数和黏度（P＜0.05）,活菌数达到8.45（lg（CFU/mL））。本研究筛选得到的植物乳杆菌A44是一株性能优良的益生乳酸菌,具有作为发酵乳益生菌辅助发酵剂的潜在应用前景。     

分离自贵州侗族苗族发酵肉中两株乳酸菌的耐受特性分析

该试验对分离自贵州侗族苗族发酵肉中的弯曲乳杆菌（Lactobacillus curvatus）LAB26（SR6）和戊糖片球菌（Pediococcus pentosaceus）LAB42（SR10-1）的耐受能力进行了研究。结果显示,2株乳酸菌均表现出良好的耐酸、耐渗透压、耐亚硝酸盐及人工模拟胃肠液耐受能力。2株乳酸菌均可在pH值为3.5的环境中生长良好,其中菌株SR6在pH值为1.5的环境中仍有生长,表现出较好的耐酸性;2株乳酸菌均可在8%NaCl溶液的环境中生长良好;2株乳酸菌在0～0.04% NaNO2条件下,代谢活跃,正常生长;2株乳酸菌在经过人工模拟胃肠液处理3 h后,活菌数仍≥5.0×107 CFU/mL。表明弯曲乳杆菌LAB26与戊糖片球菌LAB42均表现出良好的耐受性,可用于功能型食品的开发。     

Potential probiotic characterization of Lactobacillus reuteri from traditional Chinese highland barley wine and application for room-temperature-storage drinkable yogurt

The aim of this study was to select probiotic strains that could be used in drinkable yogurt to yield viable cells following storage at room temperature (RT). The uniquely high altitude conditions in Tibet and the alcoholic environment of certain products, such as the highland barley wine homemade in Tibet, may induce unusual characteristics of microbial strains. A total of 27 lactic acid bacteria were isolated from homemade highland barley wines. One strain, Lactobacillus reuteri WHH1689, demonstrated no ability for lactose utilization, exhibited a high survival rate during storage at RT in drinkable yogurts, and produced very weak post-acidification. This strain showed great resistance to conditions simulating the gastrointestinal tract, including strong adherence to HT-29 cells and inhibitory activity against Escherichia coli, Shigella flexneri, Salmonella paratyphi β, and Staphylococcus aureus. A dextran sulfate sodium (DSS)–induced mouse model was used to evaluate the in vivo influence of Lb. reuteri WHH1689 on the intestinal flora and showed that strain WHH1689 increased viable counts of bifidobacteria in feces of mice. The probiotic strain selected in this study—with its high survival at RT and lack of serious post-acidification problems—may provide significant improvements for dairy industry products by extending the storage time of dairy products with living cells.     

金鲳鱼发酵菌株筛选及其生物学特性与风味形成评价

为了有效控制发酵鱼的品质及其保质期,从传统发酵金锠鱼中筛选适合作发酵剂的菌株。以过氧化氢酶阳性、耐盐性、抗菌性及不产生组胺为筛选指标,采用稀释分离法分离目标菌株,并对其生物学特性、发酵风味与口感进行评价。结果显示,从发酵金锠鱼中分离到的38株菌株中,筛选出的两株潜在发酵菌株（zh-b和zh-f）经形态鉴定与16S rRNA分析鉴定为戊糖片球菌（Pediococcus pentosaceus）和植物乳杆菌（Lactobacillus planta-ruma）,其最适温度分别为20与30 ℃,最适pH为5、6。两株菌对金黄色葡萄球菌与大肠标杆菌均具有抗菌活性,但植物乳杆菌抗菌活性更好,且产酸能力明显高于戊糖片球菌。电子鼻对发酵产物进行测定,发现戊糖片球菌产生的甲基类、硫化物、氮氧化合物、醇类或醛酮类和有机芳香硫化物响应值（64.10、57.98、44.75、40.22和19.93）高于植物乳杆菌（5.50、34.11、10.68、0和8.95）,是香气成分的主要贡献者。电子舌测定发现,两株菌均具有产生鲜味、鲜回味的能力,且戊糖片球菌的味值分别为14.32、6.64,明显高于植物乳杆菌产生鲜味、鲜回味（3.20、2.90）,但只有植物乳杆菌产生酸味。另外,两株菌也产生非常少量的苦味。研究为两株菌作为发酵剂用于规模化生产发酵金鲳鱼提供依据。     

Survival and activity of 5 probiotic lactobacilli strains in 2 types of flavored fermented milk

The viability of 5 probiotic lactobacilli strains (Lactobacillus acidophilus LA-5, Lactobacillus casei L01, Lactobacillus casei LAFTI L26, Lactobacillus paracasei Lcp37, and Lactobacillus rhamnosus HN001) was assessed in 2 types of probiotic flavored drink based on fermented milk during 21 days of refrigerated storage (5°C). Also, changes in biochemical parameters (pH, titrable acidity, and redox potential) during fermentation as well as the sensory attributes of final product were determined. Among the probiotic strains, L. casei LAFTI L26 exhibited the highest retention of viability during refrigerated storage period, while L. acidophilus LA-5 showed the highest loss of viability during this period. The decline in cell count of probiotic bacteria in strawberry fermented milk was significantly greater compared to peach fermented milk. In an overall approach, peach fermented milk containing L. casei LAFTI L26 was selected as the optimal treatment in this study in both aspects of viability and sensory accpeptibility.