苹果酸乳酸转化高活力菌株的选育

Breeding of Malolatic Bacteria with High Malolactic Activity

选育苹果酸乳酸转化活力高的乳酸菌,为果酒的苹果酸乳酸发酵生物降酸提供新菌源。采用适宜的紫外亚硝基胍复合诱变条件处理植物乳杆菌R23,以降酸量及苹果酸乳酸转化活力为指标,对诱变获得的菌株进行筛选。紫外亚硝基胍复合诱变的适宜条件是:菌液浓度107cfu/mL,亚硝基胍质量浓度1.8 mg/mL,诱变时间60min。紫外线照射用功率15 W的紫外灯,距离20 cm,照射时间20 s。最终选育出1株降酸能力和苹果酸乳酸转化活力分别比出发菌提高77.5%与15.4%,遗传性能稳定的优良菌株RF17。

This study was intended to select a high-yield malolactic activity strain and so as to provid new bacteria source for the bio-deaeidifieation of fruit wine. LactobaciUus plantarum R23 was treated with suitable UV/NTG compound mutation condition, followed that, acid reduction level and malolactic activity were used as indexes for the screening of mutant strains. The optimum UV/NTG compound mutation conditions were got： 107 efu/mL of bacterium fulid concentra- tion,dose of NTG 1.8 mg/mL, mutation time 60 rain, the distance was 20 era, the time of irradiation was 20 s with 15 W ultraviolet lamp, a mutant strain RF17 was breeded finally, compared with the original strain, its acid reduction level and malolactic activity were respectively raised by 77.5% and 15.4%, and could be genetically stable.