饲料乳酸菌的分离鉴定及优良菌株筛选

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

对从饲料玉米、高粱、麦秆及棉花中筛选出的乳酸菌进行分类鉴定和综合性分析。用MRS+CaCO3固体培养基从棉花中分离出乳酸菌18株、高粱中30株、饲料玉米中18株、麦秆中18株。经形态学、生理生化试验进行初步鉴定并按产酸试验,耐盐及耐酸试验挑选出32株产酸率强的乳酸菌对其进行16S rDNA分子鉴定。结果显示,32株菌都具有良好的耐盐、耐酸能力;经生理生化和16S rDNA基因序列鉴定可知32株乳酸菌分属于两个属,即乳杆菌属、肠球菌属,4个种,即干酪乳杆菌(Lactobacilluscasei)、肠道球菌(Entercoccus faecium)、植物乳杆菌(Lactobacillus plantarum)、海氏肠球菌(Entercoccus hirae)。4种饲料原料中肠道球菌普遍存在。除了这种乳酸菌以外,棉花有干酪乳杆菌、植物乳杆菌、海氏肠球菌,玉米和麦秆内有植物乳杆菌。从饲料中筛选出4株具有较强产酸能力的乳酸菌,可进一步研发成青贮饲料添加剂。

It was to isolate and identify lactic acid bacteria strains which are suitable for silage additives from forage corn, sorghum, cotton and straw collected in Xinjiang Turpan. We obtained 18, 30, 18, and 18 lactic acid strains from cotton, sorghum, corn and straw, respectively, using MRS＋CaCO3solid medium. Preliminary identification of morphological, physiological and biochemical experiment were carried out to determine acid production efficiency. Finally, 32 strains of better acid-production ability were selected to identify salt tolerance, acid tolerance and the sequence analysis of 16S rDNA. The 32 strains showed satisfactory sah-tolerance and acid-tolerance ability. 16S rDNA gene sequence showed that 32 of lactic acid bacteria belonging to two genera, namely, Lactobacillus, Enterococcus, 4 species, LactobaciUus casei, Entercoccus faecium, Lactobacillus plantarum, Entercoccus hirae. In four kinds of forage ingredients, Entercoccus faecium was widespread. Besides these lactic acid bacteria, cotton has Lactobacillus casei, LactobaciUus plantarum, Entercoccus hirae, corn and straw has Laclobacillus plantarum. Four strains lactic acid bacteria with batter acid production ability were isolated from four kinds of forage which can be developed into silage additives.