产1,3-丙二醇菌株的诱变和筛选

为提高克雷伯氏肺炎杆菌产1,3-丙二醇的能力，以离子束、紫外线和氯化锂为复合诱变法，建立了产酸圈和产物耐受相结合的平板筛选方法，获得可耐受高浓度1,3-丙二醇并且副产物中乙醇含量较少的优良突变菌株2株。与出发菌株相比，两株高产突变菌株Klebsiella pneumoniae LM 03和Klebsiella pneumoniae LM05的1,3-丙二醇产量分别提高了33% 和30% ，达到66.74 g/L和65.12 g/L；乙醇产量分别降低了38% 和24% ，降低为6.59 g/L和8.05 g/L。同时测定了诱变前后还原途径中甘油脱水酶（GDHt）和1,3-丙二醇氧化还原酶（PDOR）的酶活变化，研究表明诱变对GDHt有明显的促进作用，而对PDOR的影响不明显。该诱变和筛选方法目标明确、易操作、效率高，在1,3-PD工业规模的生物法生产中将具有良好的应用价值，而且对于其他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。

Screening of Klebsiella pneumoniae Mutation for the Production of 1,3-Propanediol

Based on ion ray, ultraviolet light and LiCl mutation methods, and the theory of acid-producing circle and product tolerance capability, an effective and efficient agar plate screening technique was established, in order to increase the conversion ability of glycerol into 1,3-propanediol by Klebsiella pneumoniae. The agar plate contained acid reagent bromocresol purple and high-concentration 1,3-propanediol, in order to observe color change and product tolerance level. Two positive high-production mutant strains were selected, they not only can endure and produce high-concentration 1,3-propanediol, but also produced fewer ethanol. Compared to original strain, the 1,3-propanediol production capability of these two mutants Klebsiella pneumoniae LM 03 and Klebsiella pneumoniae LM 05 was increased by 33% and 30%, respectively, increased to 66.74 g/L and 65.12 g/L; and the final ethanol concentration was decreased by 38% and 24%, respectively, decreased to 6.59 g/L and 8.05 g/L. The activities of glycerol dehydrogenase (GDHt) and 1,3-PD oxidoreductase (PDOR) were also studied, and it was found that the activity of GDHt was enhanced, but the mutation had little influence on the activity of PDOR. The results demonstrated that the effective and efficient agar plate screening technique would be useful in the industrial biological production of 1,3-propanediol, and it also could be used for reference regarding other industrial microorganisms' mutation and screening.