小麦秸秆发酵液中优质乳酸菌的分离·纯化与鉴定

Isolation and Identification of High-Quality Lactic Acid Bacteria from Wheat Haulm

[目的]从小麦秸秆发酵液中筛选并鉴定适合于青贮添加剂的高效乳酸菌。[方法]用MRS+CaCO3固体培养基筛选,分离出78株乳酸菌;经形态学、革兰氏染色、生理生化试验、产酸效率试验、耐酸能力试验和耐盐试验等挑选出43株产酸率高的乳酸菌。通过16S rDNA法对该乳酸菌进行鉴定。[结果]已获得43株产酸能力强的菌株1,6S rDNA鉴定结果表明,37株为副干酪乳杆菌亚种(Lacto-bacillus paracasei subsp.)1,株为鼠李糖乳杆菌(Lactobacillus rhamnosus),5株为肠球菌(Enterococcus faecium)。[结论]从小麦秸秆中筛选出43株具有较强产酸能力的乳酸菌,对研发优质青贮饲料添加剂具有一定的指导意义。

[Objective] The aim of this study was to isolate and identify lactic acid bacteria（LAB） from wheat haulm and to select efficient strains for silage fermentation.[Method] From 78 LAB strains isolated on MRS＋CaCO3 solid medium,we selected 43 strains having better acid-production ability through morphological observation,Gram staining,physiological and biochemical tests,acid production test,acid tolerance test and salt tolerance test.These strains were finally identified by sequencing 16S rDNA.[Result] Of the 43 LAB strains having better acid-production ability,37 were Lactobacillus paracasei subsp.,one was Lactobacillus rhamnosusand five were Enterococcus faecium,as shown by sequences of 16S rDNA.[Conclusion] A total of 43 LAB strains having better acid-production ability were selected,which may be developed as high-quality silage additives.