【摘要】 通过对两种乳酸菌(德氏乳杆菌保加利亚亚种和唾液链球菌嗜热亚种)进行紫外线(UV)和硫酸二乙酯(DES)单因素诱变,确定了适宜紫外线照射时间、DES诱变的振荡时间;以UV和DES对两种菌进行复合诱变,筛选得到性能优良的两种乳酸菌各一株。复合诱变所得菌株的遗传性能稳定,还原糖转化率较出发菌株分别提高了24.65%和21.73%;发酵所得蜂蜜酸奶品质优良,满足了凝固型蜂蜜酸奶发酵对菌种的要求。更多还原

【Abstract】 Through mutating two acidophilus milk production strains(Lactobacillus delbrukeii subsp.bulgaricus and Streptococcus salivarius subsp.thermophillus),two high conversion ratio of reducing sugar were obtained respectively.Firstly,the ultraviolet ray(UV)and the diethyl sulfate(DES) were used to dispose these two strains separately,then selected the optimum mutation condition: irradiation time of ultraviolet ray and surging time of DES disposal.Then disposed each strain which had been mutated by UV and DES,and obtained two new strains which was very steady of genetic character and conversion ratio of reducing sugar increased 24.65%and 21.73%.The quality of the acidophilus milk which used the obtained strains to ferment honey and de greasing milk powder were all right,and the obtained strains have achieved the requirement of solidified honey yoghurt.更多还原