Interaction between lactic acid bacteria and yeasts in airag,an alcoholic fermented milk

The interaction between nine lactic acid bacteria (LAB) and five yeast strains isolated from airag of Inner Mongolia Autonomic Region, China was investigated. Three representative LAB and two yeasts showed symbioses were selected and incubated in 10% (w/v) reconstituted skim milk as single and mixed cultures to measure viable count, titratable acidity, ethanol and sugar content every 24 h for 1 week. LAB and yeasts showed high viable counts in the mixed cultures compared to the single cultures. Titratable acidity of the mixed cultures was obviously enhanced compared with that of the single cultures, except for the combinations of Lactobacillus reuteri 940B3 with Saccharomyces cerevisiae 4C and Lactobacillus helveticus 130B4 with Candida kefyr 2Y305. C. kefyr 2Y305 produced large amounts of ethanol (maximum 1.35 g/L), whereas non‐lactose‐fermenting S. cerevisiae 4C produced large amounts of ethanol only in the mixed cultures. Total glucose and galactose content increased while lactose content decreased in the single cultures of Leuconostoc mesenteroides 6B2081 and Lb. helveticus 130B4. However, both glucose and galactose were completely consumed and lactose was markedly reduced in the mixed cultures with yeasts. The result suggests that yeasts utilize glucose and galactose produced by LAB lactase to promote cell growth.     

抗水产病原菌乳酸菌的筛选及其发酵饲料的制备

为筛选具有拮抗水产病原菌特性的乳酸菌并制备发酵饲料,本试验从各类生境分离和收集乳酸菌33株,考察各菌株发酵上清液对革兰氏阴性水产病原菌的抑制作用.选用抑菌性能优良的菌株制备发酵饲料,优化发酵条件,并测定发酵饲料对水产病原菌及益生菌生长的影响.结果 表明:33株乳酸菌的发酵上清液对6株病原菌有不同程度的抑制作用,其中屎肠...     

16S ribosomal DNA analysis and characterization of lactic acid bacteria associated with traditional Tibetan Qula cheese made from yak milk

Twenty strains of lactic acid bacteria were isolated from six traditional Tibetan Qula cheese made from yak which were collected from northwest China, including Tibet, Qinghai and Gansu province. These isolates were subjected to phenotypic and genetic analyses. All isolates were Gram‐positive and catalase‐negative cocci that produced gas from glucose and formed D(–) isomer of lactate. Most isolates were able to grow in de Man, Rogosa and Sharpe (MRS) broth at pH values 3.0–9.0 and in 6.5% NaCl (w/v). According to analytical profile index 50 carbohydrates (API 50 CH) fermentation patterns of amygdalin and arabinose, these isolates were divided into three groups (A to C). On the basis of the phylogenetic trees of 16S ribosomal DNA (rDNA) sequence, the strains in all groups were placed in the cluster making up the genus Leuconostoc, which showed that all strains should belong to Leuconostoc species. Strains in Group A and Group B exhibited similarity of 16S rDNA sequence of over 99% to Leuconostoc mesenteroides, indicating that they each comprised a single species. Strains in group C were assigned to the Leuconostoc pseudomesenteroides and their 16S rDNA sequence showed a similarity of over 99%. This study demonstrated that Leuconostoc was the dominant member among lactic acid bacteria in Qula cheese.     

Impact of fermented milk on human health: Cholesterol-lowering and immunomodulatory properties of fermented milk

In this review, we focus on the cholesterol-lowering activity of Lactobacillus gasseri , the immunomodulatory function of casein phosphopeptides (CPPs) and lactic acid bacteria as starters for fermented milk, and the probability and difficulty of creating immunomodulatory fermented milk as a 'food for specified health use'. Among the starter bacteria used for the preparation of fermented milk, L. gasseri SBT0270 could exert a hypocholesterolemic effect in rats fed a diet high in cholesterol through deconjugation of bile salts. On the other hand, CPPs, having a tripeptide sequence consisting of two phosphoserine residues at N- and C-terminal positions, stimulated lymphocyte proliferation and IgA formation via the increase of interleukin-5 and interleukin-6 produced by type 2 helper T cells. The oral ingestion of CPPs enhanced the level of antigen-specific and total intestinal IgA. Moreover, one strain of bifidobacteria ( Bifidobacterium breve YIT4064) and one strain of Lactobacilli ( Lactobacillus casei strain Shirota), used as a starter for fermented milk, activated the humoral and cellular immune system, respectively, and prevented various diseases. It is important to elucidate what components modulate and what mechanisms are responsible for the physiological function of fermented milk in order for it to be accepted as a 'food for specified health use' claiming immunomodulatory activity.     

The investigation of probiotic potential of lactic acid bacteria isolated from traditional Mongolian dairy products

The aims of this study were to investigate the diversity of lactic acid bacteria (LAB) isolated from traditional Mongolian dairy products, and to estimate the probiotic potential of the isolated strains. We collected 66 samples of the traditional Mongolian dairy products tarag (n = 45), airag (n = 7), aaruul (n = 8), byasulag (n = 1) and eezgii (n = 5), from which 543 LAB strains were isolated and identified based on 16S ribosomal DNA sequence. The predominant species of those products were Lactobacillus (L.) delbrueckii ssp. bulgaricus, L. helveticus, L. fermentum, L. delbrueckii ssp. lactis and Lactococcus lactis ssp. lactis. However, we could not detect any LAB strains from eezgii. All LAB isolates were screened for tolerance to low pH and to bile acid, gas production from glucose, and adherence to Caco‐2 cells. In vitro, we found 10 strains possess probiotic properties, and almost identified them as L. plantarum or L. paracasei subspecies, based on 16S ribosomal DNA and carbohydrate fermentation pattern. These strains were differentiated from each other individually by randomly amplified polymorphic DNA analysis. Additionally, it was notable that 6/10 strains were isolated from camel milk tarag from the Dornogovi province.     

Classification of lactic acid bacteria isolated from chigee and mare milk collected in Inner Mongolia

One hundred and seventeen isolates from chigee and 191 isolates from mare milk collected in Inner Mongolia were classified into six and 10 groups, respectively, based on the protein profiles obtained by sodium dodecyl sulfate‐polyacrylamide gel electrophoresis (SDS‐PAGE). A dendrogram on the basis of the molecular sizes of the protein bands was drawn and the similarity among the groups ranged from 96% to 44%. Representative isolates from all groups were identified by 16S rDNA sequencing and a phylogenetic tree was drawn. Furthermore, the results of carbohydrate fermentation tests of all groups were compared with those obtained by 16S rDNA sequencing and SDS‐PAGE analyzes. The isolates from chigee consisted of mainly Lactobacillus sp., Lactobacillus (Lb.) plantarum, Lb. pentosus and Lactococcus (Lc.) lactis ssp. cremoris were isolated at the rates of 48, 33 and 19%, respectively. The isolates from mare milk consisted of coccus, namely, Leuconostoc (Leuc.) mesenteroides, Leuc. pseudomesenteroides, Lc. garvieae, Lc. lactis ssp. lactis, Streptococcus (Sc.) parauberis and Enterococcus (Ec.) faecium. The isolation rates were 45, 19, 7, 8, 16 and 6%, respectively. The results demonstrated that the species isolated from chigee were different from those in mare milk.     

丝状真菌YW-7与乳酸菌共同培养发酵豆粕的研究

对丝状真菌YW-7和乳酸菌混合发酵豆粕进行了研究.浅盘培养的最佳工艺条件为:料水比1:0.8,YW-7接种量2%,乳酸菌接种量1.5%,料层厚度控制在2～3cm,30℃好氧发酵24h后转为厌氧发酵48h,70℃烘干后产品平均粗蛋白含量大于53%,肽含量为23%,总酸含量2.5%,pH值4.4,对豆粕中的抗营养因子水苏糖和棉子糖具有显著的去除效果,有望成为一种良好的蛋白饲料.     

Microflora in traditional starter cultures for fermented milk, hurunge, from Inner Mongolia, China

Microflora were investigated in traditional starter cultures for fermented milk, hurunge, which are used for fermented dairy products by nomadic families in the Inner Mongolia Autonomic Region, China. The acid‐forming bacteria and yeast counts ranged from 1.8 × 10⁵ to 5.3 × 10⁸ c.f.u./g and from 6.1 × 10⁵ to 3.2 × 10⁶ c.f.u./g, respectively. Sixty‐six strains of lactic acid bacteria and 30 strains of yeasts were isolated and identified from three hurunge samples collected from the nomadic families. Lactococcus raffinolactis was the most predominant lactococci isolated from these samples. The other lactococci were Lactococcus lactis ssp. lactis, Lactococcus lactis ssp. cremoris, and Leuconostoc mesenteroides ssp. cremoris. Two major lactobacilli strains, Lactobacillus plantarum and Lactobacillus casei, were identified. In addition, Lactobacillus kefiranofaciens, Lactobacillus acetotolerans, which grew in 11% acetic acid culture medium, and Lactobacillus homohiochii, which grew in the culture medium containing 16% ethanol, were also identified. The isolated yeast strains were identified as Candida kefyr, Saccharomyces cerevisiae, Kluyveromyces marxianus var. lactis, Candida krusei and Candida valida.     

Identification of lactic acid bacteria isolated from corn stovers

One hundred and twenty‐six strains were isolated from corn stover in Henan Province, China, of which 105 isolates were considered to be lactic acid bacteria (LAB) according to Gram‐positive, catalase‐negative and mainly metabolic lactic acid product. Analysis of the 16S ribosomal DNA sequence of 21 representative strains was used to confirm the presence of the predominant groups and to determine the phylogenetic affiliation of isolates. The sequences from the various LAB isolates showed high degrees of similarity to those of the GenBank type strains between 99.4% and 100%. The prevalent LAB, predominantly Lactobacillus (85.6%), consisted of L. plantarum (33.3%), L. pentosus (28.6%) and L. brevis (23.7%). Other LAB species as Leuconostoc lactis (4.8%), Weissella cibaria (4.8%) and Enterococcus mundtii (4.8%) also presented in corn stover. The present study is the first to fully document corn stover‐associated LAB involved in the silage fermentation. The identification results revealed LAB composition inhabiting corn stover and enabling the future design of appropriate inoculants aimed at improving the fermentation quality of silage.     

乳酸菌青贮技术研究进展

本文综述了国内外乳酸菌青贮技术的内容、应用及效果, 总结了添加乳酸菌对青贮饲料发酵品质和有氧稳定性的影响, 以及不同乳酸菌菌株的筛选和鉴定及其对动物生产性能的影响。通过分析以上内容, 对乳酸菌青贮技术今后的发展方向, 特别是分子生物学在乳酸菌青贮技术研究中应用的广阔前景做了展望。     

乳酸菌在家禽生产中的应用

乳酸菌是人、畜禽胃肠道以及一些食物中的重要菌群之一,广泛用于食品、饲料和医药等领域,是一类具备多种益生功能的微生物.以乳酸菌为代表的微生态制剂,具有改善机体生长性能、促进机体免疫系统发育防止发生疾病、维持机体胃肠道微生态平衡、提升抗氧化能力、促进机体对营养物质的消化吸收等作用,一直是各大饲料企业以及家禽养殖业关注的焦点...     

乳酸菌青贮添加剂的研究与应用

很多添加剂被用来促进青贮发酵过程,其中研究最广泛的就是乳酸菌青贮添加剂。本文主要阐述了在青贮中加入乳酸菌添加剂可以促进作物的发酵速度,并且改善家畜的生产性能。     

新疆棉花秸秆中乳酸菌的分离与鉴定

实验用MRS+CaCO3固体培养基,以新疆吐鲁番地区棉花秸秆为实验对象,分离纯化得到乳酸菌4株。经形态学、生理生化特性和16S rRNA序列同源性分析进行鉴定,结果表明:Z1、Z2菌株为植物乳杆菌(Lactobacillus plantarum),Z4、Z5菌株为戊糖片球菌(pediococcus pentosaceus)。同时测定已鉴定的4株乳酸菌的产酸速率,结果发现,Z2和Z5表现出较强的产酸速率,可进一步研发成青贮饲料添加剂。     

尖叶胡枝子青贮微生物数量变化及发酵特性

以尖叶胡枝子（Lespedeza hedysaroides）为原料,对其表面附生的2株乳酸菌（LH29、LH33）的生化特性、生长特性、产酸速率进行了研究,经传统鉴定方法及16S rRNA分析方法鉴定,LH29为戊糖片球菌,LH33为植物乳杆菌;发酵初期戊糖片球菌产酸速率优于植物乳杆菌,发酵中后期后者产酸速率优于前者;将SNOW LACT L (SL)和纤维素酶(AC) 2种添加剂添加至尖叶胡枝子中,研究了不同发酵时间微生物数量的动态变化及发酵品质。发酵初期,各种微生物的数量较青贮原料上的数量有较大的增长,发酵第2天,添加AC处理组的乳酸菌数量最高,SL+AC添加组的乳酸菌的数量显著高于对照组（P＜0.05）,发酵第30天,乳酸菌、好氧细菌、酵母菌、霉菌及大肠杆菌的数量有所减少,大肠杆菌减少更明显;各添加组与对照组相比,氨态氮及丁酸含量显著降低（P＜0.05）,乳酸含量明显提高（P＜0.05）。通过Flieg青贮饲料评分方案得出直接青贮饲料的发酵品质较差,等级为劣,而添加AC及SL+AC处理的青贮饲料发酵品质Flieg等级为优。     

犊牛源乳酸菌的筛选及抑菌性能研究

从15日龄健康犊牛的肠道黏膜和食糜分离得到31株革兰氏阳性、无芽孢乳酸菌。通过耐消化道环境筛选得到4株乳酸菌M5、M7、SB1和Z4,在pH=2条件下处理2h后的存活率分别为39.24%、28.08%、44.20%、23.28%,有较强的耐牛胆盐能力,经人工胃液处理后各菌的存活率均可达到30%以上,且活菌数超过108CFU/mL。能抵御体外模拟的胃肠道逆环境的影响,且对大肠杆菌的抑制作用明显,抑菌圈直径为16～21mm。     

耐低温乳酸菌的分离与优化培养

从青贮玉米(Zea mays)以及新鲜泡菜中分离乳酸菌,通过初筛和复筛获得1株产酸能力较强的耐低温乳酸菌L2;对其进行了形态学描述和生理生化鉴定,对照伯杰式手册确定其种属;采用Box-Behnken实验设计进行培养条件优化实验,确定了该菌的最佳发酵条件。结果表明,该菌的最佳发酵条件为接种量3.1%、初始pH6.4、培养温度18.4 ℃。     

西藏地区藏北嵩草附着乳酸茵的理化特性

本研究以藏北嵩草（Kobresia littledalei）上附着的乳酸菌为研究对象,分离得到肠膜明串珠菌肠膜亚种两株,融合魏斯氏菌11株,食物魏斯氏菌6株,然后对这3种试验菌进行不同温度及pH条件下的生长试验、耐盐试验及糖发酵试验等生理生化特性的研究。结果表明,与常规条件下分离得到的相同菌株相比较,青藏高原极端环境中分离的魏斯氏乳酸菌和明串珠菌株都能在4~40 ℃的条件下生长,部分融合魏斯氏菌还可在50 ℃下微弱生长;耐酸碱试验表明,魏斯氏乳酸菌株都能在pH值为3.0和9.5的条件下生长;在耐盐性方面,部分魏斯氏菌可以在18%的NaCl下生长;在碳源利用方面,本研究提取的食物魏斯氏菌可利用半乳糖;融合魏斯氏菌可利用阿拉伯糖、蜜二糖、甘露醇。因此,藏北嵩草中所分离的乳酸菌比常规环境中的乳酸菌有较强的耐温性和耐酸碱性,而且能更广地利用碳源,从而为其在饲料青贮、酸奶发酵等方面的应用奠定基础。     

Effect of crushing unhulled rice and the addition of fermented juice of epiphytic lactic acid bacteria on the fermentation quality of whole crop rice silage, and its digestibility and rumen fermentation status in sheep

This experiment was carried out to examine the effect of crushing unhulled rice and the addition of fermented juice of epiphytic lactic acid bacteria (FJLB) on the fermentation quality of whole crop rice silage, and its digestibility and rumen fermentation in sheep. After whole rice plants (Oryza sativa L. cv. Haenuki) were harvested between the yellow and full‐ripened period of maturity, and cut at a length of 2 cm, four silage treatments were set: (i) non‐treatment; (ii) crushing treatment of unhulled rice division (crushing); (iii) addition of 1% FJLB; and (iv) crushing + addition of 1% FJLB. Lactic acid content increased with the addition of FJLB, and was highest in the crushing + FJLB treatment. Digestibilities of crude fiber, acid detergent fiber and neutral detergent fiber were significantly higher during the crushing + FJLB treatment. There were no differences among treatments in the volatile fatty acid concentrations before and after feeding. At 4 h after feeding, however, the ratio of acetic acid : propionic acid was significantly lower with the addition of FJLB. It was proven that the fermented quality of silage was improved when FJLB was added to rice plants and then ensilaged, and the digestibility of the fibrous component was raised when unhulled rice division was crushed and FJLB was supplemented.     

抑制奶牛乳房炎源金黄色葡萄球菌的乳酸菌的筛选

为获得抑制奶牛乳房炎源金黄色葡萄球菌(S. aureus)的乳酸菌(LAB),本研究从新疆巴音布鲁克牧区鲜牛乳和哈萨克族乳制品奶疙瘩样品中分离培养LAB,通过传统的分离鉴定与16S rDNA基因序列测序相结合的方法鉴定LAB种类,同时以临床奶牛乳房炎源金黄色葡萄球菌S. aureus N2为指示菌,采用双层琼脂扩散法检测分离株的抑菌能力。通过测定生长曲线确定分离株的生长稳定期,进而利用硫酸铵沉淀法透析提取稳定期内分离株的细菌素,并检测其细菌素抑菌效价。结果显示:从样品中筛选获得5株能够抑制指示菌生长的LAB,分别为希氏乳杆菌、干酪乳杆菌、粪肠球菌、戊糖片球菌和乳酸乳球菌亚种。生长规律曲线表明20 h^30 h为5株LAB的稳定期,此期培养液pH值维持在3.8~4.5。从培养20 h的5株LAB上清液中提取到了细菌素,经检测其具有抑菌活性,抑菌效价分别为457 IU/mL、1 023 IU/mL、676 IU/mL、1 862 IU/mL和1 023 IU/mL。本研究结果表明5株LAB通过在生长稳定期内维持较低酸性环境(pH<4.5),代谢产生细菌素对乳房炎源S. aureus发挥抑制生长作用。本研究为S. aureus性奶牛乳房炎的生物防治提供了实验依据。     

西藏豆科牧草青贮饲料中耐低温优良乳酸菌的筛选

本研究对西藏地区豆科牧草青贮饲料中的乳酸菌进行分离、鉴定,以期得到优良的乳酸菌菌株。以苜蓿和箭筈豌豆青贮饲料为试验材料,共分离得到6株同型发酵乳酸菌,经传统微生物培养和16S rRNA序列分析,3株(LCG9,CG35和AG11)为戊糖片球菌,2株(LCG3和LAG1)为植物乳杆菌,1株(LA3)为弯曲乳杆菌;除AG11和LAG1在5℃,LCG9和AG11在pH 3.0和8.0生长微弱外,其余乳酸菌菌株均在5~20℃,pH 3.0~8.0及3.0%和6.5% NaCl培养液中生长良好。从耐低温特性、产酸能力和发酵速率3个指标考虑,植物乳杆菌LCG3最适宜用于西藏青贮饲料生产的乳酸菌菌种。