脱硫工程菌的构建及其脱硫性能分析

以专一性脱硫菌德氏假单胞菌Pseudomonas delafieldii R-8为出发菌株, 利用pPR9TT穿梭质粒构建脱硫操纵子表达载体, 转化原始菌培养得到1株多拷贝脱硫基因的脱硫工程菌R-8-1, 并对其脱硫性能进行了研究。结果表明, 在同样的生物催化脱硫反应条件下, 工程菌的脱硫活性达到6.25 mmol DBT/g dry cell/h, 是原始菌的2倍; 柴油的脱硫试验表明, 在12 h内工程菌静息细胞能将柴油硫含量从310.8 mg/L降至100.1 mg/ L, 脱硫率达到68%, 而原始菌为53%。进一步比较了重组质粒pPR-dsz在工程菌株中传代的稳定性, 试验表明pPR-dsz在工程菌株R-8-1中具有良好的遗传稳定性。此研究为生物脱硫提供了1株优良的工程菌株, 并为该技术的应用提供了参考。

Construction and Evaluation of a Genetic Engineered Strain for Biodesulfurization

We first cloned the dsz operon of Pseudomonas delafieldii R-8 into the expressing plasmid (pPR9TT) to construct the recombinant plasmid pPR-dsz, and then reintroduced it into strain R-8 to obtain a muti-copy dsz operon engineering strain R-8-1. Compared with the wild-type, strain R-8-1 showed a higher desulfurization activity for dibenzothiophene (DBT). Initial rates of DBT removal by strain R-8-1 were 6.25 mmol/g dry cell/h, about 2-fold higher than that for wild-type strain. The recombinant cells were also applied in the desulfurization of diesel. It resulted in a 68% reduction of total sulfur from 310.8 mg/L to 100.1 mg/L, whereas only 53% of sulfur was removed by strain R-8. The stability of pPR-dsz in strain R-8-1 was studied. The results revealed the first obtain a muti-copy dsz operon engineering strain are helpful for further development in biodesulfurization.