DESIGNING A NEW RECOMBINANT STRAIN WITH ADDITIONAL COPY NUMBER OF DSZ CLUSTER TO ENHANCE BIODESULFURIZATION ACTIVITY IN PSEUDOMONAS AERUGINOSA ATCC 9027

The combustion of sulfur-rich fossil fuels leads to the release of acid rain-causing sulfur dioxide into the environment. The aim of this study was to enhance the efficiency of biodesulfurization using Pseudomonas aeruginosa through the duplication of the dsz cluster in this organism. One copy of the dsz cluster was inserted by a tri-parental mating method into the chromosome of Pseudomonas aeruginosa ATCC 9027 strain, and another copy in the form of a plasmid was cloned under control of a tac promoter. The recombinant Pseudomonas sp. was able to desulfurize dibenzothiophene more efficiently than the strains which contain only one copy of dsz cluster. Efficiency of dibenzothiophene (DBT) desulfurisation was measured through the release of 2-hidroxybiphenyle (2-HPB).This is the first time that an increase in desulfurisation activity through gene duplication has been shown.