短乳杆菌与植物乳杆菌的发酵特性

【背景】目前对于酸菜发酵的研究主要关注点是植物乳杆菌(Lactobacillus plantarum),有关短乳杆菌(Lactobacillus brevis)在酸菜方面的研究报道很少。【目的】为了挖掘短乳杆菌的发酵性能并开发酸菜发酵剂,将2株短乳杆菌分别与1株植物乳杆菌进行组合并发酵酸菜,分析短乳杆菌对酸菜发酵品质的影响。【方法】分别测定短乳杆菌与植物乳杆菌的单菌株生长产酸性能、耐酸性及亚硝酸盐降解力,并将两菌种组合后发酵酸菜,分析1-7d内酸度、乳酸菌活菌数、亚硝酸盐含量及酸菜质构特性的变化趋势。【结果】相较于短乳杆菌Lb-9-2,短乳杆菌Lb-5-3的生长和产酸速率较慢、酸耐受力较弱,但其亚硝酸盐降解力较强。两株短乳杆菌分别与植物乳杆菌Lp-9-1组合后产酸力显著增强,并在3 d时达到最低pH值(约3.10);植物乳杆菌Lp-9-1的添加使酸菜中总体乳酸菌生长延迟,在5 d时达到最高活菌数;组合菌种的样品中亚硝酸盐含量在1-7 d内变化较为平缓,前5天内两个组合之间差异不显著;接种乳酸菌会降低酸菜硬度和弹性,发酵3d时Lb-5-3/Lp-9-1组合的硬度最大,感官评价得分最高。【...     

阴道中益生特性乳杆菌的分离与功能评价

目的分离健康女性阴道中的乳杆菌并鉴定其益生特性,为开发治疗妇科疾病的复方益生菌制剂提供新型菌株。方法采集健康女性阴道分泌物并分离筛选乳杆菌,通过16SrDNA序列分析鉴定乳杆菌分离株,并对其产酸性能、产H2O2能力、抑菌能力、产生物膜能力进行检测。结果从50名健康女性阴道内共分离出179株乳杆菌,其中卷曲乳杆菌101株、詹氏乳杆菌42株、格氏乳杆菌26株、植物乳杆菌5株、唾液乳杆菌3株以及干酪乳杆菌2株。179株乳杆菌中有146株具有产酸能力,发酵液pH值的最低的5株菌分别为卷曲乳杆菌J3、卷曲乳杆菌J8、詹氏乳杆菌J87,植物乳杆菌J75以及格氏乳杆菌J35,其pH分别为4.20、4.23、4.24、4.26及4.36;产H2O2弱阳性菌株有87株、阳性有37株、强阳性有9株,这9株菌分别为卷曲乳杆菌J3、卷曲乳杆菌J8、卷曲乳杆菌J20、詹氏乳杆菌J87,詹氏乳杆菌J90、詹氏乳杆菌J15、格氏乳杆菌J11、植物乳杆菌J75、植物乳杆菌J69以及植物乳杆菌J40;能拮抗大肠埃希菌的菌株有115株、拮抗金黄色葡萄球菌的有84株、拮抗白假丝酵母的有52株;经统计,对三者同时有拮抗作用且作用最强的只有6株,分别为卷曲乳杆菌J3、卷曲乳杆菌J50、卷曲乳杆菌J62、詹氏乳杆菌J87、詹氏乳杆菌J16和格氏乳杆菌J66;不同乳杆菌产生物膜能力数值范围在1.0~5.4,卷曲乳杆菌、詹氏乳杆菌、干酪乳杆菌的生物被膜形成能力显著高于其他三种菌(P0.05)。在全部179株菌中,卷曲乳杆菌J3和詹氏乳杆菌J87既具有强的产酸能力和产过氧化氢能力,又有较强抑菌活性,同时产生物膜能力也最强。结论卷曲乳杆菌J3和詹氏乳杆菌J87具有优良的生物学特性,有望成为用于治疗妇科疾病微生态制剂的备选菌株。     

饲料乳酸菌的分离鉴定及优良菌株筛选

对从饲料玉米、高粱、麦秆及棉花中筛选出的乳酸菌进行分类鉴定和综合性分析。用MRS+CaCO3固体培养基从棉花中分离出乳酸菌18株、高粱中30株、饲料玉米中18株、麦秆中18株。经形态学、生理生化试验进行初步鉴定并按产酸试验,耐盐及耐酸试验挑选出32株产酸率强的乳酸菌对其进行16S rDNA分子鉴定。结果显示,32株菌都具有良好的耐盐、耐酸能力;经生理生化和16S rDNA基因序列鉴定可知32株乳酸菌分属于两个属,即乳杆菌属、肠球菌属,4个种,即干酪乳杆菌(Lactobacilluscasei)、肠道球菌(Entercoccus faecium)、植物乳杆菌(Lactobacillus plantarum)、海氏肠球菌(Entercoccus hirae)。4种饲料原料中肠道球菌普遍存在。除了这种乳酸菌以外,棉花有干酪乳杆菌、植物乳杆菌、海氏肠球菌,玉米和麦秆内有植物乳杆菌。从饲料中筛选出4株具有较强产酸能力的乳酸菌,可进一步研发成青贮饲料添加剂。     

五株乳酸菌和三株芽孢杆菌的生物学特性和功能

【背景】乳酸菌和芽孢杆菌是应用于生产最多的益生菌,但不同菌株间的生长特性均不相同,因此了解菌株的生物学特性具有重要意义。【目的】研究菌株的生物学特性,能合理地开发和利用菌株,以保证菌株生产应用的安全性。【方法】活化后鉴定5株乳酸菌和3株芽孢杆菌并对其形态进行观察,探究菌株的生长曲线、产酸能力及最适生长条件,测定菌株的抑菌活性和产酶性能,同时探究菌株的益生性和安全性。【结果】五株乳酸菌分别编号鉴定为干酪乳杆菌R1、副干酪乳杆菌R2、香肠乳杆菌R3、福莱乳杆菌R4和唾液乳杆菌R5;3株芽孢杆菌分别编号命名为贝莱斯芽孢杆菌Y1、枯草芽孢杆菌Y2和地衣芽孢杆菌Y3。八株菌形态结构均不相同但都为杆状,均在2–10 h为对数生长期,18–24 h为稳定期,培养24 h时乳酸菌和芽孢杆菌的活菌数均保持在10⁹和10⁸ CFU/mL,最适生长温度为37.0℃。乳酸菌具有较强的产酸能力和抑菌活性,芽孢杆菌有较强的产酶性,在人工胃液中都有较强的耐受性。八株菌都无溶血活性、无毒力基因、对抗生素都保持中度敏感以上;其中唾液乳杆菌有四环素耐药基因,但对四环素抗性为中度敏感。【结论】八株菌生长繁殖速度快,乳酸菌产酸能力和抑菌活性较强,芽孢杆菌具有较强的产酶性能,在体外具有较好的益生性和安全性,可应用于生产实践。     

葡萄藤叶青贮中乳酸菌的分离与鉴定

为了筛选出性状优良的乳酸菌菌株,本试验以实验室纯培养方式从葡萄藤叶自然发酵的青贮中分离鉴定乳酸菌。经过菌落形态、细胞形态、生理生化鉴定和16S r DNA基因序列以及系统发育树的分析,从葡萄藤叶青贮中分离出5株乳酸菌,其中菌株P-1. 2和P-2. 2为戊糖乳杆菌(Lactobacillus pentosus),菌株P-1. 7为戊糖片球菌(Pediococcus pentosaceus),菌株P-2. 1为粪肠球菌(Enterococcus faecium),菌株P-2. 3为短乳杆菌(Lactobacillus brevis)。测定产酸速率和生长速率,发现菌株P-2. 1的产酸能力和生长性能最好。     

女性阴道中产细菌素的乳杆菌筛选与鉴定

目的对从60例健康女性阴道中筛选出产生细菌素的优势乳杆菌进行鉴定,并为研制开发微生态制剂提供优良可靠菌种。方法利用牛津杯法筛选出19株乳杆菌,其菌株发酵乳酸量高并且产生细菌素。对19株乳杆菌进行了多项理化鉴定。结果19株乳杆菌分别为：格氏乳杆菌9株,唾液乳杆菌1株,卷曲乳杆菌9株。结论筛选的19株乳杆菌是健康女性阴道中的优势有益菌,具有较强的产酸能力,都产生细菌素,其中16株产生过氧化氢,某些菌株具有较高的生产应用价值。     

从人胃肠道源乳杆菌株中初步筛选耐酸耐胆盐优良株

目的筛选对酸和胆盐耐受性均较强的优良乳杆菌株。方法模拟人体胃酸环境（pH=3）和十二指肠高胆盐环境（胆盐含量=3‰）测定104株人胃肠道源乳杆菌在酸性及高胆盐环境下作用4h后的存活菌数,并与对照相比较。对结果进行统计学分析。结果16株菌在酸性环境及高胆盐环境下4h后的活菌下降对数值均小于2。筛选出3株具有较强耐酸耐胆盐能力的乳杆菌株。结论大多数人胃肠道源乳杆菌对酸和胆盐的耐受能力均不强,对酸的耐受性普遍强于对胆盐的耐受性。     

洱海沉积物中反硝化细菌的分离与反硝化作用研究

自洱海十个点位的沉积物中富集筛选出101株反硝化细菌并从中筛选出1株较强反硝化能力的细菌,命名为EH314。该细菌接触酶(过氧化氢酶)试验、产硫化氢试验和淀粉水解均为阳性,葡萄糖氧化发酵实验结果为氧化菌,产脂酶(Tween 80)试验结果为阴性;初步鉴定该菌为产碱杆菌属细菌;对细菌反硝化能力进行测定发现,菌株EH314能有效地降解水体中的硝酸盐且反硝化可在有氧条件下进行。     

可抑制致病菌的益生菌筛选及抑菌物质的初步确定

为了得到可抑制致病菌的益生菌并初步确定其抑菌物质。从土壤、饲料添加剂和肥料添加剂3种样品中初筛能产生抑菌圈的菌株。用牛津杯法,对初筛得到的菌株和实验室保存的菌株进行复筛。对复筛的未知菌株进行形态学、16S r RNA基因序列和生理生化特征鉴定。对复筛菌株的发酵上清液进行酸碱作用验证、高温处理、蛋白酶处理、盐析处理和透析处理,再进行抑菌活力测定。结果显示复筛中有8株对大肠杆菌、金黄色葡萄球菌和藤黄微球菌都有较强抑制作用的菌株。8株菌中有4株已知菌,4株未知菌。已知菌株分别为保加利亚乳杆菌、干酪乳杆菌、鼠李糖乳杆菌和植物乳杆菌。4株未知菌中3株被鉴定为地衣芽孢杆菌,1株被鉴定为乳酸片球菌。地衣芽孢杆菌能产生多种耐高温的抑菌物质,其中包含能透过8-14 k D透析袋的小分子和不能透过8-14 k D透析袋的大分子,初步判定为多肽类物质。5株产酸菌株产生的抑菌物质主要是酸性物质。     

一株源自人体阴道抗真菌的 优势乳杆菌的分离、筛选及鉴定

摘要：目的 筛选并鉴定出可以抗真菌且益生特性优良的乳杆菌菌株,为研制预防和治疗人体真菌性阴道炎症的微生态制剂奠定坚实的理论基础。方法 利用经典的微生物方法,将健康人体阴道内乳杆菌分离出来;利用发酵工程学、细胞生物学以及药理学方法,将分离出的乳杆菌中益生特性优良且可以抑制白假丝酵母菌的优势菌株筛选出来,利用分子生物学方法,将筛选出的优良乳杆菌菌株进行鉴定。结果 筛选出1株产酸性能优良,产过氧化氢,具有较强黏附能力,且能够抑制白假丝酵母菌的优势乳杆菌菌株,此菌株经鉴定为Lactobacillus crispatus。结论 本实验从健康人体阴道内分离、筛选并鉴定出的1株可抗真菌性能优良乳杆菌菌株SQ004,具有制备预防和治疗人体真菌性阴道炎症微生态制剂主要菌株的条件。     

Lactic acid bacteria isolated from soy sauce mash in Thailand

Fourteen sphere-shaped and 30 rod-shaped lactic acid bacteria were isolated from soy sauce mash of two factories in Thailand. These strains were separated into two groups, Group A and Group B, by cell shape and DNA-DNA similarity. Group A contained 14 tetrad-forming strains, and these strains were identified as Tetragenococcus halophilus by DNA similarity. Group B contained 30 rod-shaped bacteria, and they were further divided into four Subgroups, B1, B2, B3, and B4, and three ungrouped strains by phenotypic characteristics and DNA similarity. Subgroup B1 contained 16 strains, and these strains were identified as Lactobacillus acidipiscis by DNA similarity. Subgroup B2 included two strains, and the strains were identified as Lactobacillus farciminis by DNA similarity. Subgroup B3 contained five strains. The strains had meso-diaminopimelic acid in the cell wall, and were identified as Lactobacillus pentosus by DNA similarity. The strains tested produced DL-lactic acid from D-glucose. Subgroup B4 contained four strains. The strains had meso-diaminopimelic acid in the cell wall, and they were identified as Lactobacillus plantarum by DNA similarity. Two ungrouped strains were homofermentative, and one was heterofermentative. They showed a low degree of DNA similarity with the type strains tested, and were left unnamed. The distribution of lactic acid bacteria in soy sauce mash in Thailand is discussed.     

Characterization of Lactobacillus sakei by the type of stereoisomers of lactic acid produced

Lactobacillus sakei strains were characterized by the shift of the type of stereoisomers of lactic acid produced in the presence of 50 mM sodium acetate in a medium. Of 27 Lactobacillus sakei strains studied, 20 strains showed high levels of DNA-DNA similarity with L. sakei NRIC 1071(T), and were confirmed as L. sakei. The three remaining strains were identified as Lactobacillus curvatus by DNA-DNA similarity, and three other strains were included in the cluster of Lactobacillus plantarum/Lactobacillus pentosus/Lactobacillus paraplantarum and one strain in the cluster of Lactobacillus paracasei on the basis of 16S rRNA gene sequences. Of the 20 L. sakei strains, 19 strains shifted the type of stereoisomers of lactic acid produced from the DL-type to the L-type in the presence of 50 mM sodium acetate. L. curvatus strains and strains included in the cluster of L. plantarum/L. pentosus/L. paraplantarum and in the cluster of L. paracasei did not shift the type of stereoisomers of lactic acid produced. The change of the type of stereoisomers of lactic acid from the DL-type to the L-type in the presence of sodium acetate was concluded to be species-specific for L. sakei and useful for identification of strains in this species.     

Lactic acid bacteria found in fermented fish in Thailand

Forty-seven strains of homofermentative rod-shaped and 5 heterofermentative sphere-shaped lactic acid bacteria were isolated from 4 kinds of fermented fish (pla-ra, pla-chom, kung-chom, and hoi-dong) in Thailand. These bacteria were separated into four groups by phenotypic and chemotaxonomic characteristics, including fluorometric DNA-DNA hybridization. Five strains (Group I) contained meso-diaminopimelic acid in the cell wall. Four strains were identified as Lactobacillus pentosus, and one strain was L. plantarum. Tested strains of this group produced DL-lactic acid. The rest of the rod-shaped bacteria, 23 strains (Group II) and 19 strains (Group III), lacked meso-diaminopimelic acid in the cell wall and were identified as L. farciminis and Lactobacillus species, respectively. The tested strains of these groups produced L-lactic acid. The amount of cellular fatty acids of C16:0 and C18:1, and the DNA base compositions were significant for differentiating the strains in Groups II and III. Five strains of cocci in chains (Group IV) produced gas from glucose. The tested strains of this group produced d-lactic acid. They were identified as a Leuconostoc species. The distribution of these bacteria in fermented fish in Thailand is discussed.     

体外拮抗幽门螺杆菌的人嗜酸乳杆菌菌株的选育

目的 探讨人嗜酸乳杆菌对幽门螺杆菌（Ｈｅｌｉｃｏｂａｃｔｅｒ ｐｙｌｏｒｉ,ＨＰ）毒力株的体外拮抗作用,筛选出对ＨＰ毒力株有明显拮抗作用的嗜酸乳杆菌菌株。方法 从健康人胃肠道中分离出５２株嗜酸乳杆菌可疑株,通过其培养特性,生理特性,生化反应及代谢产物测定等进行鉴定,获得２６株嗜酸乳杆菌。同时,从临床患者胃活检标本中分离出２３株ＨＰ菌株,用ＰＣＲ方法筛选出ｃａｇＡ阳性ＨＰ毒力株,然后,采用打孔法进行嗜酸乳杆菌培养上清拮抗ＨＰ毒力株的实验,以１％的乳酸作对照。结果 筛选出４株对ＨＰ毒力株有明显拮抗作用的嗜酸乳杆菌,这种拮抗作用不依赖嗜酸乳杆菌分泌的乳酸。结论 人嗜酸乳杆菌在体外对ＨＰ毒力株具有明显拮抗作用。该研究为应用微生态疗法治疗ＨＰ感染提供了理论基础。     

云南泡梨中乳酸菌的分离鉴定及其应用

【背景】泡梨是云南省常见的一种腌渍水果,在云南加工食用已经有一百多年的历史,因其味道酸甜可口、风味独特而深受人们喜爱,而目前对泡梨中微生物种群的系统分析和发酵原理的研究尚未见报道。【目的】研究乳酸菌在云南泡梨中的分布及应用,阐明乳酸菌种类对泡梨发酵中风味物质的影响。【方法】从云南省4个不同地区采集12份泡梨样品,经菌落菌体形态、生理生化特性和16SrRNA基因序列分析进行菌种分离与鉴定。利用分离的乳酸菌为菌种进行泡梨的制备,采用GC-MS技术对人工接种的复合乳酸菌发酵与自然发酵泡梨进行风味物质的分析与感官评价。【结果】分离鉴定出79株植物乳杆菌(Lactobacillus plantarum)、 3株类植物乳杆菌(Lactobacillus paraplantarum)、1株戊糖乳杆菌(Lactobacillus pentosus)、1株干酪乳杆菌(Lactobacillus casei)、2株副干酪乳杆菌(Lactobacillus paracasei)和1株短乳杆菌(Lactobacillus brevis),植物乳杆菌为泡梨发酵中的优势菌。将分离所得乳酸菌用于泡梨制备的结果表明,乳酸菌使泡梨的发酵时间缩短5d且品质更优,分析其中的风味物质发现接种乳酸菌发酵泡梨风味物质更丰富,其中酯类和醇类远多于自然发酵泡梨。【结论】云南泡梨中含有丰富的乳酸菌,选用分离出的优势乳酸菌作为复合乳酸菌用于泡梨发酵获得色泽、口感更好的泡梨,且发酵周期更短,风味物质更丰富。该研究对泡梨制备工艺和进一步标准化生产均具有重要意义。     

酸马奶中乳酸菌的鉴定及生物学特性的研究

[目的]对从酸马奶中分离出来的10株乳酸菌进行鉴定和生理生化特性研究,为工业生产筛选特性优良的菌种.[方法]通过形态学观察、生理生化特性、分子生物学特性及其对致病菌抑制作用的研究对其进行鉴定,并筛选特性优良菌株.[结果]10株乳酸菌分别为2株Lactobacillus plantarum、2株Enterococcus villorum、2株Enterococcus dispar、3株Enterococcus durans和1株Enterococcus raffinosus;其对Staphylococcus aureus、Escherichia coli和Enteritidis bacillus有不同程度的抑制作用.[结论]菌株HZ24、HZ25具有良好的生物学特性和益生功能,可以应用到食品发酵工业生产中.     

Comparative analysis of amylolytic lactobacilli and Lactobacillus plantarum as potential silage inoculants

Abstract Two starch-degrading Lactobacillus strains, Lactobacillus amylovorus NRRLB4540 and Lactobacillus amylophilus NCIB11546, were assessed for their potential as silage inoculants. Lactobacillus amylovorus was considered suitable as a silage inoculant for crops which are low in water-soluble carbohydrate, but contain starch, which is unavailable to most conventional silage inoculants. This was on the basis of it exhibiting similar growth characteristics to an inoculant strain of Lactobacillus plantarum and secreting an amylase which was optimally active in the silage pH range. Lactobacillus amylophilus was found to be intolerant of low acid conditions but displayed considerable potential for the industrial production of lactic acid from inexpensive starch-based substrates as it fermented sugars to the desirable L(+) isomer of lactic acid only.     

Preliminary assays for the development of a probiotic for goats

In order to determine probiotic properties, 137 strains of lactic acid bacteria from the feces of Creole goats were screened, only six were resistant to pH 2.0 and bile salts (0.3%). Three strains identified as Lactobacillus and two as Enterococcus showed agglutination with the treated yeast. Between them, Lactobacillus DDL17, DDL19, DDL48 and Enterococcus DDE39 demonstrated high specificity in this test because the correspondent agglutination was inhibited by one sugar, suggesting the presence of a lectin-like structure in their cell walls, which could be due to adhesion ability. Another Enterococcus strain (DDE55) showed low affinity because five sugars inhibited the agglutination of the treated yeasts. The results of hydrophobic properties showed that the strains who were able to agglutinate yeasts presented similar hydrophobic characteristics as hexadecane, xylene and toluene, but high specificity was not related to a high hydrophobicity. Only two strains (Lactobacillus DDL19 and DDL48) showed aggregation with the lowest concentration of ammonium sulfate, complementing the hydrophobicity assay. Only one strain, Lactobacillus DDL48, showed an inhibition against an enteric indicator strain (Salmonella Typhimurium and Escherichia coli O111). This inhibitory action was not affected by the addition of catalase and no inhibition was detected after neutralizing the supernatant culture fluid. These strains could be pre-selected in order to complete studies focused on designing a probiotic for use in goat feed.