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．     

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.     

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。     

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.     

两株乳酸菌的分离鉴定及产酸性能的研究

从泡菜中分离筛选出两株乳酸茵Lactll和Leull,根据形态特征、生理生化特性进行初步鉴定,并选取室温(白天20℃左右,晚上12℃左右),25℃,37℃三种温度对两株乳酸茵进行培养,通过定时测定两株乳酸菌在三种不同温度下的pH值来考察不同乳酸菌的产酸性能.经初步鉴定,两菌株分别为短乳杆菌、乳球菌.对这两菌株产酸性能的测试结果表明.两株乳酸菌在37℃下培养产酸速率快,同一温度下培养,Leull产酸速率大于Lactll.     

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。     

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.     

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.     

Production of conjugated linoleic acids by Lactobacillus plantarum strains isolated from naturally fermented Chinese pickles

Naturally fermented pickles harbour many lactic acid bacteria (LAB). Forty-three LAB strains with conjugated linoleic acid (CLA)-producing ability were isolated from three naturally fermented pickle brines. Of these isolates, lp15 identified as Lactobacillus plantarum by API 50 CHL system and full-length 16S rDNA sequence analysis exhibited the highest CLA-producing ability (26.1% conversion) at 48 h in de Man Rogosa Sharpe (MRS) broth in the presence of 100 μg/ml of linoleic acid (LA). Compared to other strains, L. plantarum strain lp15 showed the highest tolerance upon increased levels of LA in the medium, i.e., up to 600 μg/ml. This strain converted about 25% of LA into CLA isomers [predominantly cis-9, trans-11 CLA (9-CLA) and trans-10, cis-12 CLA (10-CLA)], of which 75% was 9-CLA. Interestingly, though the conversion rate of LA into CLA by lp15 remained stable between 100 to 600 μg/ml LA levels in the medium, it dropped sharply at 1000 μg/ml. Taken together, the lp15 strain displayed relatively high LA tolerance with higher conversion rate, which implies that this strain is a valuable candidate for enhancing the CLA content in food-sources like pickles.     

Wetland bacteria isolated from Huangpu River-Yangtze River estuary and its degradation on diesel

Oil contaminated soil was collected from Huangpu River-Yangtze River estuary wetland, with the aim of isolating oil-degrading microorganisms and evaluating their ability to degrade diesel. Three bacterial strains were discovered and identified by sequencing their 16S rDNA genes, two were Pseudomonas and one was Alcaligcnes. The proper growth conditions of each bacterium were measured and presented for diesel biodegradation. Biodegradation assays revealed that the degradation rates of three bacterial strains were 42.5%, 14.6% and 15.9% in 7 d respectively. They all play an important role on the nalkanes within the range of C16-C25 components of diesel. The results indicated that the oil-degraders can adapt to degrade diesel. The bacterial strains can be used in wetland diesel pollution control.     

Spoilage potential of psychrotrophic bacteria isolated from raw milk and the thermo-stability of their enzymes

The storage and transportation of raw milk at low temperatures promote the growth of psychrotrophic bacteria and the production of thermo-stable enzymes, which pose great threats to the quality and shelf-life of dairy products. Though many studies have been carried out on the spoilage potential of psychrotrophic bacteria and the thermo-stabilities of the enzymes they produce, further detailed studies are needed to devise an effective strategy to avoid dairy spoilage. The purpose of this study was to explore the spoilage potential of psychrotrophic bacteria from Chinese raw milk samples at both room temperature (28 °C) and refrigerated temperature (7 °C). Species of Yersinia, Pseudomonas, Serratia, and Chryseobacterium showed high proteolytic activity. The highest proteolytic activity was shown by Yersinia intermedia followed by Pseudomonas fluorescens (d). Lipolytic activity was high in isolates of Acinetobacter, and the highest in Acinetobacter guillouiae. Certain isolates showed positive β-galactosidase and phospholipase activity. Strains belonging to the same species sometimes showed markedly different phenotypic characteristics. Proteases and lipases produced by psychrotrophic bacteria retained activity after heat treatment at 70, 80, or 90 °C, and proteases appeared to be more heat-stable than lipases. For these reasons, thermo-stable spoilage enzymes produced by a high number of psychrotrophic bacterial isolates from raw milk are of major concern to the dairy industry. The results of this study provide valuable data about the spoilage potential of bacterial strains in raw milk and the thermal resistance of the enzymes they produce.     

Voices from Manukau: recruitment and success of traditionally under represented undergraduate groups in New Zealand

This paper describes a research project, “Voices from Manukau”, that investigated the impact of a joint initiative by a university and an institute of technology in New Zealand. The purpose of the initiative was to increase the participation of students traditionally under represented at tertiary-level study, particularly Māori (indigenous people) and individuals from Pacific Island nations. Many of the participants were adults who had not experienced high levels of success during their compulsory period of education and they lived in low socio-economic areas. We found that participation of under-represented groups increased. The “Manukau” students were as successful as other undergraduate students studying at the university. Of particular interest was the high level of success of Māori and Pacific Island students.     

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。     

环新疆经济圈视角下新疆矿产资源开发问题浅析

新疆地处欧亚大陆腹地,位于"环新疆经济圈"13个经济体的核心位置,与其他国家相比,拥有经济、地理、交通等地缘优势.在环新疆经济圈视角下开发新疆矿产资源,不仅可以利用两种资源,实现周边国家资源互补,也可确保我国矿产资源的战略安全.     

白酒大曲中产淀粉酶细菌的快速分离

用固体碘熏蒸显示透明圈的方法,快速从白酒大曲中分离出产淀粉酶的细菌菌株6株,对分离出的6菌株所产淀粉酶进行了淀粉酶活性测定,进一步确定LY菌株为高产淀粉酶菌株,并对LY菌株所产淀粉酶的酶学性质进行了研究。     

内地新疆高中班学生学习适应性研究

运用周步成AAT量表,对广州内地新疆高中班学生学习适应性实施整群调查研究.结果呈现,总体上学习适应情况良好,性别上没有显著差异,不同年级存在显著差异,反映出随学习任务要求的变化而起伏的基本规律,它为这一特殊群体跨文化背景下的学习适应性辅导提供参照.     

酸性蛋白酶产生菌的筛选及其部分性质研究

以市售固体酒曲为实验材料,采用酪蛋白溶圈法及福林酚法对高产蛋白菌株进行了筛选,并对其部分生化性质进行了研究.结果表明:筛选得到的菌株DBM2初步鉴定为芽孢杆菌,其最适温度为30℃,最适pH值为5,为酸性蛋白酶产生菌.     

酸奶中乳酸菌的分离及发酵风味物质测定

利用MRS琼脂培养基对酸奶中的乳酸菌进行分离,共分离出A1、S2两株乳酸菌。对两株菌在牛奶中的发酵风味物质进行研究,结果表明:两株菌均有较强的酸度、乙醛和丁二酮生成能力。     

Reomoval of Heavy Metals from Aqueous Solutions using Bascteria

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