中文摘要：

以K.pneumoniae为出发菌株,通过紫外线和氯化锂诱变筛选PQQ高产菌.结果表明,当紫外照射时间为45s时,致死率为85％;当氯化锂剂量为0.3％时,致死率达85％.紫外诱变所得菌株U1和U2的PQQ产量分别是出发菌株的2.7倍和6倍.氯化锂诱变所得菌株L1的PQQ产量是出发菌株的5倍.紫外线和氯化锂复合诱变所得菌株F1的PQQ产量是出发菌株的1.4倍.紫外诱变所得菌株U2经连续传代15次,其PQQ产量仍能达到原代菌的95％,表明该菌能稳定生产PQQ.该研究为进一步提高PQQ产量奠定了基础.

英文摘要：

Klebsiella pneumoniae can naturally synthesize PQQ for harboring intact gene cluster. To achieve high yield strain, in this work, the wild type K. pneumoniae was mutated by ultraviolet rays （UV） radiation and LiC1 treatment. The UV-induced lethality was 85% when ir- radiating time was 45 s, while LiCl-induced lethality was 85% when using 0.3% LiC1. Consequently, four mutants： U1, U2 by UV, L1 by LiC1, and F, by UV-LiC1 complex mutation, produced 2.7, 6.0, 5.0 and 1.7-fold of PQQ compared with the wild type K. pneumoniae. Par- ticularly, the U2 strain could produce 95% PQQ after 15 generations of subculture, suggesting that this strain will stably synthesize PQQ. This study provided basis for further enhancement of PQQ production.