青贮饲料中乳酸菌的分离鉴定及优良菌株筛选

Isolation and Identification of Lactic Acid Bacteria from Silage and Filtering of Excellent Strains

为研究青贮饲料中乳酸菌的分类及形态学与生理生化特性,从苜蓿（Medicago sativa L.）及玉米（Zea maysL.）青贮饲料中分离得到5株乳酸菌。经16S rRNA序列分析,2株（GI7,GI24）为乳酸片球菌（Pediococcus acidi-lactici）,其余3株（GI11,GI44,GI62）分别为戊糖片球菌（Pediococcus pentosaceus）、弯曲乳杆菌（Lactobacillus cur-vatus）和植物乳杆菌（Lactobacillus plantarum）;5株菌均为同型发酵乳酸菌,除弯曲乳杆菌GI44在pH3.0,4.0,8.0等条件下不能生长外,其余菌株均可在5,10,40,45℃等不同温度条件下、pH3.0~8.0等环境下以及3.0%和6.5%NaCl溶液中良好生长或微弱生长。同时,通过产酸速率和生长曲线等指标筛选出产酸较快、生长迅速的GI62可作为制备乳酸菌青贮饲料添加剂的优良菌株。

To study the taxonomic,morphologic,physiological and biochemical characteristics of lactic acid bacteria（LAB） in silage,five strains of LAB were isolated from alfalfa（Medicago sativa L.）and maize（Zea mays L.）silage.The 16S rRNA sequence analysis indicate that two strains are Pediococcus pentosaceus（GI7,GI24）,and the other three are Pediococcus acidilactici,Lactobacillus curvatus and Lactobacillus plantarum（GI11,GI44,GI62）.Each is homofermentative lactic acid bacteria and can grow well or weakly at 5,10,40,45℃,and with pH3.0~8.0,3.0% and 6.5% NaCl except that GI44 does not grow at pH3.0,4.0,8.0.Through measuring the rate of lactic acid production and the growth curve,GI62 was selected as eximious strain used for preparing lactic acid bacteria additive due to its rapid acid-production and growth speed.