乳酸菌原生质体融合筛选

Protoplast fusion and screening of lactic acid bacteria

对从市售酸乳中分离的嗜热链球菌和保加利亚乳杆菌进行原生质体融合,用再生的菌落和原始菌进行发酵,筛选出凝乳好且产酸量高的融合子;再用高温法筛选耐热性好的融合子。实验结果显示用溶菌酶处理后得到2种菌的原生质体,在融合了3min后所涂的平板上长出了12株再生菌落,观察凝乳结果表明4、6、8号菌为凝乳快且好的融合子:从酸度测量结果分析得出4、5、6、8号菌为产酸量高的融合子;利用高温法依据菌的耐热性优点筛选出4号和8号菌的最高耐受温度为56℃。

Streptococcus thermophilus and Lactobacillus bulgaricus isolated from commercial yogurt were used as original sWains for protoplast fusion. By fermentation with regeneration strains and original strains, the fusion hybrids, which performed good at coagulation and acid production, were isolated. Besides, the good heat-tolerance fusion hybrids were screened by high temperature method. The results showed that 12 colonies of regenerated strains appeared on the media after disposing the original strains by lysozyme and fusing for 3 min. With solidify test, sWain 4#, 6#, 8# were proved to be good fusion hybrids at clabbering. With acidity test, sWain 4#, 5#, 6#, 8# were proved to be good fusion hybrids at acid production. By high temperature test, stain 4# and 8# were screened out with highest growing temperature of 56℃.