以实验室保存的经过低温混合诱导的乳酸菌菌株Q1-4-6为研究对象,通过生长及产酸情况,研究其在低温条件下对于各种营养素的需求,以期为工业大规模生产提供数据参考.低温条件下通过研究碳源对菌株生长及产酸的影响发现,麦芽糖和乳糖对于菌株的生长及产酸有非常好的促进作用,菌株在以蔗糖为碳源的培养基中生长缓慢,而在以乳糖为碳源的培养基中生长最好.3种氮源对于菌株生长的差异不显著,以酵母膏为氮源的菌株生长略好于其他2种.不同浓度金属离子对于菌株生长有不同影响,Zn2+的促生长作用略高于Fe2+,Zn2+浓度越低,菌株生长越好,高浓度的Zn2+则对菌株生长有抑制作用.Fe2+浓度为0.5 g/L时,菌株生长最好,Fe2+浓度过高或过低对于菌株的生长都有抑制作用.根据16S rDNA序列分析结果,同时结合形态学特征、生理生化特性,将菌株鉴定为棉籽糖肠球菌(Enterococcus raffinosus).%Lactic acid bacterial strain Q1-4-6 collected in the laboratory after mixed induction in low temperature was taken as a research object. Its various nutrition element demands under cryo-conditions were studied so as to provide data references for large scale industrial production. It was found through study on the effect of carbon source on the growth and acid production of the strain under cryo-conditions that maltose and lactose had very good promotion to the strain growth and acid production. It grew slowly in the medium with sucrose as carbon source, but grew the best in the medium with lactose as carbon source. Three different kinds of nitrogen source had no obvious effect on the strain growth; it grew slightly better using yeast extract as nitrogen source than another two. Different concentrations of metal ions had different effects on its growth strains, Zn2+ was slightly better than Fe2+ in growth promotion, the lower concentration of Zn2+ the better it grew. High concentration of Zn2+ inhibited the strain growth. When the concentration of Fe2+ was at 0.5 g/L, it grew the best. Fe2+ concentration could inhibit the strain growth whether it was loo high or too low. The strain was classified as Enlerococcus raffinosus according to its 16S rDNA sequence combined with morphology, the physiological and biochemical features.
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