产1,3-丙二醇菌株克雷伯氏肺炎杆菌的诱变与筛选研究

Study on screening of Klebsiella pneumoniae mutation for the production of 1,3-propanediol

为提高克雷伯氏肺炎杆菌Klebsiella pneumoniae产1,3-丙二醇的能力,尝试使用紫外线和氯化锂对菌种进行复合诱变,利用产酸圈和产物耐受相结合的平板筛选方法,获得可耐受高质量浓度1,3-丙二醇且副产物中乙醇及乳酸含量较少的优良突变菌株2株。与出发菌株相比,2株高产突变菌株Klebsiella pneumoniae Kc和Klebsiella pneumoniae Kd发酵最终1,3-丙二醇质量浓度分别提高了34.7%和35.2%,达到66.7 g/L和67.1 g/L;乙醇质量浓度分别降低了49.3%和47.1%,降低至8.1 g/L和8.4 g/L;乙酸质量浓度分别提高了61.5%和68.1%,达到14.7 g/L和15.3 g/L。结果表明,该诱变和筛选方法目标明确、易操作、效率高,在1,3-丙二醇工业规模的生物法生产中将具有良好的应用价值,而且对于其它具有工业应用价值的菌株筛选工作也具有一定的借鉴意义。

The ultraviolet （UV）light and LiCl methods were used to carry out mutagenesis to the Klebsiella pneumoniae, in order to increase the conversion capacity of glycerol into 1,3-propanediol（1, 3-PD）. Based on the theory of acid-producing circle and product tolerance capability, the effective and efficient agar plate screening technique was established. Using this approach, two mutant strains that endured higher concentrations of 1,3-PD and yield less byproduct of ethanol and lactic acid were a- chieved. Compared to the original strain, the final 1,3-PD concentration of broth produced by these two mutant strains Klebsiella pneumoniae Kc and Klebsiella pneumoniae Kd was increased by 19.5% and 22.1% ,up to 66.7 g/L and 67.1 g/L respectively;acetate acid concentration increased by 61.5% and 68. 1%,up to 14. 7 g/L and 15.3 g/L respectively; ethanol concentration reduced to 49. 3% and 47. 1% ,to 7.1 g/L and 7.4 g/L,respectively. The results demonstrated that the effective and efficient agar plate screening technique would be useful in the industrial biological production of 1,3-PD, and it could be reference by other industrial microorganisms＇ mutation and screening.