青藏高原几种牧草附着耐低温乳酸菌的筛选

Screening of Cryophilic Lacto-Bacteria from Several Qinghai-Tibet Plateau Herbages

为筛选出适宜青藏高原低温发酵优良菌株,针对从青藏高原垂穗披碱草(Elymus nutans)、燕麦(Avena satival L.)和藏嵩草(Koeleria tibetica)中分离出的148株乳酸菌,经10℃低温条件下MRS液体培养基与不同培养时间(12、24、36和48 h)初筛后,进一步将初筛的菌株通过不同温度(10、15和25℃)条件下绿汁发酵液的复筛,并对其进行生理生化特性研究。结果表明,植物乳杆菌(Lactobacillus plantarum)31、干酪乳杆菌(Lactobacillus casei)Q5、戊糖片球菌(Pediococcus pentosaceus)Q6和棒状乳杆菌(Lactobacillus coryniformis)Q7这4株菌在MRS液体培养基和绿汁发酵液较低温环境中生长活性和快速产酸能力较强,而且生理生化特性指标表明,Q5比对应模式菌具有更广泛的糖源利用能力,Q7较对应模式菌具有更强的耐酸和耐低温特性。因此,上述4株乳酸菌可作为适宜青藏高原低温发酵青贮饲料备选菌株。

In order to screen lacto-bacteria（ LAB） that can adapt low temperature fermentation in Qinghai-Tibet Plateau 148 strains from Elymus nutans,oat and Koeleria tibetica in Qinghai-Tibet Plateau were isolated. These strains were confirmed as cryophilic LAB by means of culture medium under 10 ℃ for different time（ 12,24,36 and 48 h）and rescreened by fermented in green juice at 10 ℃,15 ℃ and 25 ℃,as well as studied their physiological and biochemical characteristics. The results showed that strains 31（ Lactobacillus plantarum）,Q5（ Lactobacillus casei）,Q6（ Pediococcus pentosaceus）,and Q7（ Lactobacillus coryniformis） performed higher activity and acid-producing ability in MRS medium and fermented in green juice,and the physiological and biochemical characteristics indexes indicted that Q5 could performed more kinds of carbohydrates than corresponding model strain,Q7 had stronger acid and low temperature resistance properties than model strain. The above four LAB strains can be alternative strains for low temperature fermentation of ensilage in Qinghai-Tibet Plateau.