耐高温乳酸菌的筛选

通过初筛、复筛,获得一株耐高温且产酸能力较强的菌株Y5,对该菌株进行了形态学和生理生化特性鉴定,确定此菌株为乳酸茵．通过单因素试验和正交试验确定菌株Y5的最佳产酸条件：发酵温度为55℃,转速为60r／min,接种量为7％,装液量为100mL．     

泡菜中乳酸菌的筛选及其生物学特性的研究

从泡菜中分离出4株具有乳酸菌菌落特征的菌株,菌株编号分别为L1、L2、L3和L4.经革兰氏染色,光学显微镜观察,生理试验等初步鉴定为乳酸菌.4株菌均为乳杆菌,其中菌株L4是较理想的纯种发酵菌株.     

高效秸秆发酵剂优良菌种的分离筛选与鉴定

用ＳＬ选择性培养基从青贮饲草中分离出１０株乳酸菌,并从革兰氏染色特性、形态特征、培养特性和生化反应等方面进行了初步鉴定。结果明串株菌２株、片球菌２株、植物乳杆菌３株、发酵乳杆菌３株。按不同菌株搭配制成发酵剂。经发酵剂处理的秸秆喂牛增重效果显著。     

产EPS乳链球菌的筛选

本研究从新采集的鲜牛奶、蔬菜及青草中分离筛选到数株乳酸菌.通过凝乳实验、生理生化实验、耐性实验确定两株为胞外多糖产量较高的乳链球菌PB1和PB6,其中PB1菌株初步鉴定为乳脂链球菌.     

产溶栓酶纳豆菌的筛选及特性的研究

本文主要阐述了产溶栓酶纳豆菌的筛选、鉴定及最适固态发酵条件的初步研究。采用纤维蛋白平板法在经初筛获得 1 5株产溶栓酶菌株基础上 ,经复筛确定一产酶活力最高菌株 -B .N .1 0 ,并对该菌株部分生物学特性进行了研究 ,以B .N .1 0菌株进行固态发酵 ,其产酶最适温度、时间分别为 30℃和 2 4h     

温度和pH值对大球盖菇菌丝生长的影响

本文对大球盖菇茵丝生长的温度和pH值进行了研究，结果发现供试菌株在5—35℃范围内菌丝都可以生长，但不同温度条件下菌丝生长速率不同，最适生长温度为25℃。菌株在培养基pH5-pH11范围内都可以生长，大部分菌株最适生长pH值为7。     

凉州熏醋大曲中细菌区系研究

研究了凉州熏醋传统酿造大曲中细菌区系,对大曲中的细菌总数、醋酸菌、乳酸菌及耐热菌进行计数、分离纯化和鉴定,通过显微镜镜检、革兰氏染色、接触酶反应、需氧型、产酸产气、发酵性等特性测定,对分离的菌株进行了具体菌属鉴定.结果表明,大曲表面与大曲中心细菌区系差异明显;大曲中共分离到5株醋酸菌、8株乳酸菌和4株耐热菌;醋酸菌分属为醋杆菌属和葡糖杆菌属;乳酸菌分属为糖球菌属、链球菌属、魏斯氏菌属、乳球菌属和索丝菌属;耐热菌分属为微球菌属和芽孢杆菌属.     

耐热木聚糖酶源细菌筛选、鉴定及酶学性质

利用木聚糖作为唯一碳源的基础盐培养,在50℃培养条件下,从新乡周围土样及腐殖质中筛选到1株产耐热β-木聚糖酶细菌,初步鉴定为巨大芽孢杆菌（Bacillus megaterium FLH-2）.该菌株在40~55℃生长良好,最适生长温度50℃.木聚糖酶粗酶性质研究表明：该酶最适pH和最适温度分别为6.0和65℃;在pH 5.0~9.0及温度30~75℃之间酶活相对稳定,分别处理30 min,相对酶活仍保持在80%以上.     

木糖渣生物转化产乳酸的初步研究

用两步法将玉米棒芯生产木糖后剩下的废物木糖渣生物转化为乳酸,先用纤维素酶水解木糖渣生成葡萄糖;然后用乳酸菌发酵葡萄糖产乳酸。纤维素酶水解的最佳条件为pH=4．8,水解温度50℃,水解时间48h,此时葡萄糖含量可达41．76g·L-1。混合菌比例5：1,温度40℃左右,时间32h为乳酸菌发酵产乳酸的最佳条件,温度42C时发酵液中乳酸含量可达2．12g·L^-1。     

一株纤维素酶高产菌的分离及鉴定

为了对筛选得到的1株纤维素分解菌进行鉴定,并研究其对废弃秸秆资源的降解效果.本文通过羧甲基纤维素钠(CMC)固体培养初筛和复筛,从土壤中获得了1株酶活力较高的菌株,并对其进行不同碳源酶活力的初步研究.利用PCR法,结合18S rDNA的序列分析鉴定该菌株为产黄青霉菌,将该菌株接种到不同碳源的发酵培养基中,30℃培养48 h后测定酶活,发现该菌株不到12 h对滤纸完全崩解;15 d内对小麦秸秆分解迅速.同时测得羧甲基纤维素酶活力、滤纸糖化力和小麦秸秆纤维素分解能力分别为:4.653 U/m L、5.445 U/m L和6.876 U/m L.     

乳酸菌的抗肿瘤作用及其机理

乳酸菌具有抗肿瘤作用，且副作用甚微，其作用机理较复杂，人们对其认识还很肤浅．本对乳酸菌的抗肿瘤作用机理进行了探讨．     

乳酸菌的筛选及生物学特性的研究

从酸奶样品中分离、筛选出5株乳酸菌,经过形态学测试及生理生化反应试验,最后确定其中2株为嗜热链球菌.     

乳酸菌的生理功能及在饲料发酵中的应用

乳酸菌具有促进营养物质的消化和吸收、降低血清胆固醇、调节肠道菌群平衡、激活机体免疫系统、改善食品风味和预防癌症等多方面的生理功能。利用益生乳酸菌发酵而成的饲料对促进动物的健康生长具有重要的实践意义,这种功能性发酵饲料近年在我国畜牧业中发展十分迅速,有着广阔的生产和应用前景。本文就近几年来关于乳酸菌的生理功能、益生菌发酵饲料的种类及乳酸菌发酵饲料在动物生产中的应用进行综述,并对其发展前景进行展望。     

乳酸菌发酵剂生物工程技术研究

当前我国生物工程技术的发展速度较快,并且也被广泛地应用在了农业、制药、化工生产、环保技术等多个领域,其中乳品发酵制备工艺当中生物工程技术的应用范围较广。本文即是对乳酸菌发酵剂的生物工程技术进行研究,首先介绍了乳酸菌发酵工程当中涉及的生物工程技术,并对乳酸菌育种途径进行阐述,以期能为相关工作提供参考。     

波能酒疗对运动性疲劳及血乳酸的影响

目的:研究波能酒疗对人体运动性疲劳及血乳酸(BLA)的影响。广东省柔道队20名男运动员以递增负荷蹬踏功率自行车至力竭,随机分为对照组和波能酒疗组进行单盲试验。在运动前、结束后5min及8h取上臂静脉血2ml,测RPE、脉搏及血清BLA含量。运动后8h时,波能酒疗组RPE、BLA含量明显低于对照组(p<0.05)。结论:波能酒疗能加速运动性疲劳消除,这与加速机体血乳酸的清除有关。     

Screening beneficial bacteriostatic lactic acid bacteria in the intestine and studies of bacteriostatic substances

Lactic acid bacteria(LAB) are a representative probiotic. As the dominant flora in the human intestinal tract, LAB can regulate the balance of human intestinal flora and improve host health. The purpose of this study was to isolate and screen LAB that are well suited to the intestinal characteristics of the Chinese population, with excellent probiotics and high antibacterial activity. After 16 S ribosomal RNA(rRNA) homology and phylogenetic tree analysis, potential probiotics were tested for their antibacterial activity, resistance to artificial gastrointestinal fluid and drugs, surface hydrophobicity, and safety.Three strains of LAB with acid resistance, bile salt resistance, epithelial cell adhesion, and no multidrug resistance were selected: Lactobacillus salivarius, Leuconostoc lactis, and Lactobacillus paracasei. Analysis of the antibacterial active substances in the three strains and their fermentation broths revealed that the main antibacterial substances of L. lactis were organic acids, whereas those of L. salivarius and L. paracasei were organic acids and bacteriocins with broad-spectrum antibacterial activity. These three strains of probiotic LAB with high antibacterial activity were identified as bacterial resources that could potentially be used to develop probiotic preparations for the prevention and treatment of intestinal diseases caused by intestinal pathogens.     

Probiotic properties of lactic acid bacteria isolated from traditionally fermented Xinjiang cheese

Six lactic acid bacterial (LAB) strains were isolated from traditionally fermented Xinjiang cheese and evaluated for functional and probiotic properties and potentials as starter cultures. The isolated six LAB strains comprised Lactobacillus rhamnosus (one strain), Lactobacillus helveticus (one strain), and Enterococcus hirae (four strains). All of the six strains were tolerant to acidic and bile salt conditions. Among which, the L. rhamnosus R4 strain showed more desirable antimicrobial, auto-aggregation, and hydrophobic activity. In addition, the strain L. rhamnosus R4 exhibited the highest level of free radical scavenging activity (53.78% of 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radicals and 45.79% of hydroxyl radicals). L. rhamnosus R4 also demonstrated cholesterol and triglyceride degradation by 50.97% and 28.92%, respectively. To further examine the health-promoting effects of these LAB strains on host lifespan, Caenorhabditis elegans was used as an in vivo model. Worms fed LAB as a food source had significant differences in lifespan compared to those fed Escherichia coli OP50 (as a negative control). Feeding of L. rhamnosus R4 extended the mean lifespan of C. elegans by up to 36.1% compared to that of the control. The results suggest that the strains isolated from Xinjiang fermented dairy products have high potential as starter cultures in the cheese industry.     

Natural populations of lactic acid bacteria in douchi from Yunnan Province, China

This research was aimed at isolating and identifying the predominant lactic acid bacteria (LAB) in the traditional Chinese salt-fermented soybean food, douchi, from Yunnan, China. The predominant LAB present were isolated and identified by conventional culture-dependent methods combined with molecular biological methods. Two hundred and sixty isolates were obtained from thirty kinds of traditional fermented douchi from six cities and counties in Yunnan, and those strains were divided into twelve groups by their morphological and biochemical characteristics. Based on 16S ribosomal DNA (rDNA) sequencing and analysis, 56 representative strains were identified as belonging to 6 genera and 14 species: Lactobacillus (4 spp.), Weissella (3 spp.), Pediococcus (2 spp.), Staphylococcus (2 spp.), Enterococcus (1 sp.), and Bacillus (2 spp.). The results show that douchi contains a large natural population of LAB of diverse composition from which some strains could be selected as starters for functional fermented foods. This is the first study on the original douchi from Yunnan, and the results suggest that it may be a useful source for the isolation of LAB. This study has also laid a foundation for further research on developing functional douchi products.