Abstract: In order to screen out excellent lactic acid bacteria strains for low-temperature silage in alpine areas,the experiment isolated lactic acid bacteria strains from three types of pasture silage:Vicia sativa,Triticosecale wittmack and Avena sativa,screened them through low-temperature culture and acid production tests,identified their morphology,physiology and biochemistry,and analyzed 16S rDNA homology. The results showed that 42 strains of lactic acid bacteria were isolated and purified from 3 types of pasture silage,and 10 strains of low-temperature tolerant lactic acid bacteria with strong low-temperature growth ability and acid production ability were screened,of which 7 strains were homofermentative lactic acid bacteria and 3 strains were heterofermentative lactic acid bacteria. All 10 strains had good acid resistance,salt tolerance and temperature tolerance. According to homology sequencing analysis,strains GN1,GN3 and GN10 were Lactiplantibacillus plantarum,strains GN2,GN4 and GN7 were Levilactobacillus brevis,strains GN5 and GN6 were Latilactobacillus curvatus,and strains GN8 and GN9 were Latilactobacillus sakei subsp.. Taking into account various results such as the acid production ability,low-temperature growth ability and physiological and biochemical characteristics of low-temperature tolerant lactic acid bacteria,Lactobacillus plantarum GN1,GN3 and GN10 and Lactobacillus brevis GN7 were suitable as candidate strains for low-temperature silage fermentation in plateau areas.

Key words: Gannan region, Silage, Low temperature, Lactic acid bacteria

摘要： 为筛选出适宜高寒地区低温青贮的优良乳酸菌菌株，本试验从箭筈豌豆(Vicia sativa)、小黑麦(Triticosecale wittmack)和燕麦(Avena sativa)3种牧草青贮饲料中分离乳酸菌菌株并通过低温控制培养及产酸试验进行筛选，对菌株进行形态、生理生化鉴定及16S rDNA同源性分析。结果表明，从3种牧草青贮牧草分离纯化得到42株乳酸菌，筛选得到具有较强低温生长能力和产酸能力的10株耐低温乳酸菌，其中7株为同型发酵乳酸菌，3株为异型发酵乳酸菌，10株菌株都具有较好的耐酸性、耐盐性和耐温性，经同源性测序分析菌株GN1，GN3和GN10为植物乳杆菌(Lactiplantibacillus plantarum)，菌株GN2，GN4和GN7为短乳杆菌(Levilactobacillus brevis)，菌株GN5和GN6为弯曲乳杆菌(Latilactobacillus curvatus)，菌株GN8和GN9为清酒乳杆菌(Latilactobacillus sakei subsp.)。结合耐低温乳酸菌产酸能力、低温生长能力和生理生化特性等多种结果综合考虑，植物乳杆菌GN1，GN3和GN10及短乳杆菌GN7适宜作为高原地区低温青贮发酵的备选菌株。

关键词: 甘南地区, 青贮, 低温, 乳酸菌