脱硫工程菌的构建及其脱硫性能分析

Construction and Evaluation of a Genetic Engineered Strain for Biodesulfurization

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6.25μmol DBT/g dry cell/h,是原始菌的2倍;柴油的脱硫试验表明,在12h内工程菌静息细胞能将柴油硫含量从310.8mg/L降至100.1mg/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。

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 muff-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 μnol/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 muff-copy dsz operon engineering strain are helpful for further development in biodesulfurization.