单亲灭活保加利亚乳杆菌与嗜热链球菌抗噬菌体菌株融合子的选育

Breeding of fusant between single inactivated Lactobacillus bulgaricus and bacteriophage-resistant mutant of Streptococcus thermophilus

摘要: 为获得具有抗噬菌体功能且发酵性能优良的乳酸菌酸奶生产菌株,将生产用保加利亚乳杆菌制备原生质体后高温灭活,灭活后的原生质体与嗜热链球菌抗噬菌体菌株的原生质体通过PEG6000诱导进行融合,并对融合子性能进行研究。结果从20株融合子中挑选出3株具有噬菌体抗性且发酵性能优良的乳酸菌融合子。融合条件为:以PEG6000（浓度为400 g/L,添加0.01 mol/L Ca Cl2、0.02 mol/L Mg Cl2）为促融剂,40℃融合2 min。此条件下,融合率可达1.85×10-6。获得的融合子在凝乳、产酸、产粘性物质、产香气成分及抗噬菌体方面性能优越,适合于酸奶生产。

Abstract: To obtain yogurt production strains with functions of phage resistant and good fermentation performance,protoplast fusion between single inactivated Lactobacillus bulgaricus and bacteriophage-resistant mutant of Streptococcus thermophilus was performed by the induction of PEG6000 and the performances of fusant were studied. Finally,three lactic acid bacteria fusants with functions of phage resistant and good fermentation performance were selected from 20 fusants that were obtained through fusion. The fusion rate reached 1.85 ×10-6after 2 min of infusion at 40 ℃ in the PEG6000. The performances of the fusant were superior at producing acid,solidifying milk,producing good smell and resisting phage,so it was applicable to yoghurt production.