【作者】 戴甄；

【导师】 李学如；

【作者基本信息】 西南交通大学 ， 微生物与生化药学， 2013， 硕士

【摘要】 乳酸菌是一类近年来国内外研究较多的益生菌,乳酸菌自身及其代谢产物对人和动物具有保健和治疗疾病的效果。布氏乳酸杆菌与其他乳酸菌相比较,国内外对其了解还不充分,因此对其生理、生化特性及其相关代谢产物的研究具有一定的科学意义和应用价值。实验利用改良的MRS培养基从泡菜发酵汁,发酵青贮饲料等富含乳酸杆菌的介质中分离出6株乳酸菌,经过16S rDNA鉴定,它们分别为乳酸乳球菌(Lactococcus lactis)、植物乳杆菌(Lactobacillus plantarum)、鼠李糖乳杆菌(Lactobacillus rhamnosus)、戊糖乳杆菌(Lactobacillus pentosus)、干酪乳杆菌(Lactobacillus casei)、布氏乳酸杆菌(Lactobacillus buchneri)。通过SDS-PAGE分析上述菌株S-层蛋白显示,与分离的其他几株乳酸菌相比较,实验分离出的布氏乳酸杆菌(布氏乳酸杆菌LBZ8菌株)表层含大量S-层蛋白,为此本实验以LBZ8菌株为研究对象,对该菌生长及其相关特性进行研究,结果显示,LBZ8对1.Ommol/L的过氧化氢(H2O2)具有很强的耐受能力,对超氧阴离子(O2-)、羟自由基和1,1-二苯基-2-三硝基苯肼自由基(DPPH)的清除能力分别达到43.12%、86.52%、40%。与文献报道比较显示出较强的抗氧化性能。发酵试验研究结果表明,该菌发酵液中γ-氨基丁酸(GABA)的含量为11.588mg/ml, D-甘露醇含量为19.46mg/ml。抑菌试验研究结果表明,LBZ8的发酵液对大肠杆菌(Escherichiacoli),白色念球菌(Canidia Albicans)具有一定的抑制生长的作用,但对金黄色葡萄球菌(Staphylococcus aureus)的抑制效果不太明显。LBZ8的发酵液对上述病原菌具有很强的凝集作用,能够使微生物细胞大量的沉集。用PAGE胶蛋白微量回收试剂盒纯化得到的S-层蛋白,对大肠杆菌,金黄色葡萄球菌,猪链球菌(Streptococcus suis)和白色念球菌,具有一定的粘附性,能够绑定到微生物细胞的细胞表面,同时能促进这些微生物细胞凝集。本课题所分离的布氏乳酸杆菌LBZ8生长迅速,具有很强的抗氧化和自由基的清除能力,其代谢产物中含有GABA和D-甘露醇,对大肠杆菌和白色念珠真菌具有抑制作用,同时该菌能在细胞表面表达大量的S-蛋白。S-层蛋白能够帮助微生物细胞在不良的环境中保持细胞完整的活性,帮助乳酸杆菌定植于小肠上皮细胞上,减少病原菌的定植,布氏乳酸杆菌LBZ8这些特性为该菌在医疗、食品、饲料等领域的应用提供了可能,具有一定的开发利用价值。更多还原

【Abstract】 Lactobacillus spp is one of the normal mieroflora in human and animal intestinal and vaginal tracts, and can exert Probiotie effects through competitive colonization, improvement of intestine microecologieal environments, and enhancement of immune functions.In this paper6strains of Lactobacillus spp were isolated from natural fermented vegetable juice, and silage feed in modified MRS medium, and identified through conventional classification methods including colony characteristics, cell morphology, physiological and biochemical properties, as well as16S rDNA sequence analysis. They were Lactococcus lactis, Lactobacillus plantarum, Lactobacillus rhamnosus, Lactobacillus pentosus, Lactobacillus casei, and Lactobacillus buchneri. The S-layer protein of each isolated strain was analysised by SDS-PAGE. The result showed that Lactobacillus buchneri LBZ8expressed more S-layer protein than that of the others. The growth and characteristics of LBZ8strain were investigated. The results showed that the LBZ8has strong tolerance in1.Ommol/L of hydrogen peroxide (H2O2). Clear rate of superoxide anion (O2-), hydroxyl radical and DPPH were43.12%,86.52%,40%respectively. The contentration of GABA and D-mannitol is11.588mg/mL, and19.46mg/mL respectively in the fermentated liquid of LBZ8strain. The fermentated liquid showed the inhibitory effect against Escherichia, Candida albicans, and strong ability of agglutinating pathogenic bacteria. The S-layer protein was purified by Micro protein PAGE Recovery Kit. The purified S-layer protein can adhere to cell surface of Escherichiacoli, Staphylococcus aureus, Canidia Albicans, Streptococcus suis. At the same time S-layer proteins also showed the ability to aglutinate these bacteria.Lactobacillus Buchneri LBZ8grow rapidly, and have strong abilities of antioxidant and freeradical scavenging and can product GABA and D-mannitol, inhibiting the growth of E.coli and Candida albicans. A lot of S-layer proteins were expressed on the cell surface of Lactobacillus Buchneri LBZ8. These features of LBZ8make it have a value for development and utilization in the industries of medical, food, and feed.更多还原