野生型乳酸菌的分离·筛选及鉴定

Isolation,Screening and Identification of Wild Lactic Acid Bacteria

[目的]研究从传统乳制品中分离鉴定出乳酸菌,并对其发酵性能进行简单筛选。[方法]以10份传统自制酸乳食品为样品,对发酵性能优良的乳酸菌进行了分离、鉴定和产酸性研究。[结果]样品中共分离出55株乳酸菌,经凝乳试验筛选出27株凝乳效果较好的乳酸菌,鉴定为有乳杆菌属13株、乳球菌属2株和肠球菌属8株。将凝乳最快的2只杆菌SC1、SC4和1只球菌EB1以及按1∶1复配的SC1+EB1和SC4+EB1 5个样品发酵复原乳,分别测定了这5种发酵剂在37和42℃下发酵2～9 h产酸的速率。结果表明,分离得到的菌种37℃下产酸速率都大于42℃下的;且相比单个菌种,复配后的菌种发酵的酸乳产酸速率在37和42℃下都属于中速,但最终酸度最适合饮用,口感最佳。[结论]研究可为以后挑选出优良的野生菌种提供参考。

[Objective] To study isolating lactic acid bacteria from traditional dairy products,and simply screening its fermentation performance.[Method] With 10 traditional indigenous dairy products as samples,lactic acid bacteria with superior fermentation properties were isolated,identified,the acid production was also studied.[Result] There are 55 lactic acid bacteria in the samples,among which,total of 27 strains of lactic acid bacteria were isolated and identified into three genera Lactobacillus（13 isolates）,Lactococcus（2 isolatees） and Enterococcus（8 isolates）.After identification,3 isolates were selected and mixed.Potential of these isolates for lactic acid production were also observed at 37 ℃ and 42 ℃ for 9hrs with one hour intervals.There were generally trend that acid production at 37 ℃ were faster than 42 ℃.Mixed isolates were slow at acid production,but they could ferment yoghurt with better taste.[Conclusion] The study could provide reference for selecting superior wild bacteria.