China Biotechnology. 2006, 26(06): 59-64.
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.
