氮源对德氏乳杆菌保加利亚亚种B61-3耐冻干能力的影响  

Effect of Nitrogen Source on Freeze-dried Resistance of Lactobacillus delbrueckii subsp.bulgaricus B61-3

作　　者：汤静月 葛绍阳[2] 桑跃 赵亮[2,4] 刘贵巧[1] TANG Jingyue;GE Shaoyang;SANG Yue;ZHAO Liang;LIU Guiqiao(College of Life Science and Food Engineering,Hebei University of Engineering,Handan 056038,China;Probiotics Research Center,China Agricultural University,Sanhe 065200,China;College of Food Science and Engineering,Gansu Agricultural University,Lanzhou 730070,China;Key Laboratory of Functional Dairy,Ministry of Education,College of Food Science and Nutritional Engineering,China Agricultural University,Beijing 100083,China)

机构地区：[1]河北工程大学生命科学与食品工程学院,河北邯郸056038 [2]中国农业大学益生菌研究中心,河北三河065200 [3]甘肃农业大学食品科学与工程学院,甘肃兰州730070 [4]功能乳品教育部重点实验室,中国农业大学食品科学与营养工程学院,北京100083

出　　处：《食品工业科技》2023年第11期144-152,共9页Science and Technology of Food Industry

基　　金：国家自然科学基金(32072196)。

摘　　要：本研究针对德氏乳杆菌保加利亚亚种B61-3,分别测定了其对16种氮源的利用情况,筛选出能够提高菌株冻干耐受的氮源种类及添加量,并进一步测定该氮源对菌株冻干粉发酵活力、菌体形态、发酵关键酶活力的影响。结果表明:氮源为30 g/L牛骨蛋白胨时可提高菌株冻干存活率及冻干粉发酵活力,冻干存活率由9.68%提高到18.90%,冻干粉平均发酵活力较对照组提高22.15%;电子显微镜显示,牛骨蛋白胨培养后菌体大小及形态有所改变,对照组发酵菌体表现出不规则、卷曲的形态且菌体较长,而牛骨蛋白胨为氮源时菌体形态呈表面光滑的短杆状,菌体长径比(l/d)和面积体积比(S/V)显著降低(P<0.05),可能与菌株更高的存活率和发酵活力有关。发酵关键酶活力测定结果表明,冷冻干燥显著降低菌株酶活力(P<0.05),牛骨蛋白胨培养菌株冻干后胞内酶活力均显著高于对照组(P<0.05),乳酸脱氢酶、Na^(+)K^(+)-ATP酶及β-半乳糖苷酶分别较对照组提高1.30、1.52及2.75倍,且胞外β-半乳糖苷酶活性低于对照组。结果证实,牛骨蛋白胨培养B61-3菌体能够抵抗冷冻干燥过程对菌体细胞膜造成的损伤,减少酶外泄,从而提高冻干存活率和发酵活力。In this study,the utilization of 16 nitrogen sources of Lactobacillus delbrueckii subsp.bulgaricus B61-3 were determined,and the types and amounts of nitrogen sources that can improve the freeze-drying tolerance of the strain were screened out.More importantly,the effects of nitrogen source modification on the fermentation performance,cell morphology and enzyme activities of freeze-dried powder of the strain were investigated.The results showed that 30 g/L of bovine bone peptone improved the freeze-drying survival rate from 9.68%to 18.90%,and increased fermentation activity by 22.15%compared with the control group.Changed cell size and morphology of the cultured cells of bovine bone peptone were also observed by electron microscope.Cell cultured in bovine bone peptone medium represented a short rod with smooth surface,and the ratio of length to diameter or area to volume decreased significantly(P<0.05).However,cells in the control group showed irregular,curly shape and longer cells.Freeze-drying significantly reduced the enzyme activity of the strain(P<0.05).Compared with control group,the intracellular activities of these enzymes in the cells cultured in bovine bone peptone significantly increased after freeze-drying(P<0.05),and the activities of lactate dehydrogenase,β-galactosidase and Na^(+)K^(+)-ATPase increased by 1.30 times,1.52 times and 2.75 times respectively,while the extracellular activities ofβ-galactosidase decreased.Meanwhile,the results showed that B61-3 cells cultured with bovine bone peptone could resist the damage of cell membrane caused by freeze-drying process,reduce the leakage of enzymes,thus improving the freeze-drying survival rate and fermentation activity.

关 键 词：德氏乳杆菌保加利亚亚种 氮源 冷冻干燥 发酵活力 菌体形态 

分 类 号：TS201.3[轻工技术与工程—食品科学]