【摘要】 本研究应用基因组改组提高鼠李糖乳杆菌的耐糖能力,进而提高L-乳酸的产量。通过紫外线和亚硝基胍诱变方法获得8株改良出发菌株。考察了氨基酸前处理和变溶菌素对原生质体形成的影响。利用双亲灭活的原生质体进行递进式融合,经过两轮基因组改组和碳酸钙高糖平板及瓶筛选,选育出了耐糖改组菌株F2-2。在初糖浓度为150g/L发酵罐中,F2-2的乳酸产量为140g/L,是野生型乳杆菌的1.8倍。结果表明基因组改组技术能够快速提高乳酸菌耐糖和产酸能力两个表型。更多还原

【Abstract】 In this paper,application of the genome shuffling in improving the glucose tolerance of Lactobacillus rhamnosus MEE539 and enhance the L-lactic acid production was studied.The starting population was generated by ultraviolet irradiation and nitrosoguanidine mutagenesis.The effect of amino acid and mutanolysin on protoplast formation was investigated.The positive colonies from library created by inactivated protoplasts were more likely to be screened on plates containing different concentrations of high glucose and 2% CaCO3.Characterization of all mutants and wide-type strain in shake flask indicated the compatibility of two optimal phenotypes of glucose tolerance and lactic acid enhancement.The lactic acid production of F2-2 from the second round genome shuffled population was 1.8 fold higher than that of the wild type at the initial glucose concentration of 150 g/L in 16l bioreactor.更多还原