绿色化工新例—利用基因重组蓝细菌生产PHB的初步结果

Preliminary Results on PHB Production by Recombinant Cyanobacterium in Line with Green Chemical Industry

在发现蓝细菌糖原合成与PHB合成相竞争的基础上,提出用基因工程手段改造蓝细菌,使催化糖原合成的关键酶ADP-葡萄糖焦磷酸羧化酶的agp基因部分为红霉素抗性基因所取代,从而将与PHB合成形成竞争反应的糖原合成途径删除. 对该突变株的构建过程及培养进行了初步研究,所得突变株生长速度提高,最终生物量较野生株高,表明突变株细胞的光合效率较野生株细胞提高. 在突变株体内未检测到糖原,光合自养时PHB含量由野生株的3.4%提高到约15%.

Based on the understanding that the cyanobacterial glycogen biosynthesis is a competitive pathway to cyanobacterial PHB biosynthesis, a genetically engineered cyanobacterium was constructed by partially replacing the agp gene encoding the ADP-glucose pyrophosphorylase involved in cyanobacterial glycogen synthesis by an erythromycin resistance cassette. The obtained mutant propagated faster and the final biomass was higher against its wild-type species, which indicated a much higher photosynthetic efficiency in the mutant. No glycogen was detected in the mutant. Under the photoautotrophic condition, the intracellular PHB content was improved to 15% of the dry weight as compared to 3.4% in the wild-type strain.