Isolation of the Pseudomonas aeruginosa gene affecting uptake of dibenzothiophene in n-tetradecane
2003
Honda, K. (Japan Cooperation Center, Petroleum, Shimizu, Shizuoka. Bio-Refining Process Lab.) | Watanabe, K., Maruhashi, K.
The dsz desulfurization gene cluster from Rhodococcus erythropolis KA2-5-1 was transferred into the chromosomes of Pseudomonas aeruginosa strain NCIMB9571 using a transposon vector. All of the recombinant strains completely desulfurized 1 mM dibenzothiophene (DBT) in n-tetradecane (n-TD) except one, named strain PARM1. Strain PARM1 was unable to desulfurize DBT in n-TD, but was able to desulfurize it in water. The n-alkane utilization ability, the biosurfactant production and the fatty acid composition of cells in strain PARM1 were the same level as those of the other recombinants. The transposon insertion area of strain PARM1 was analyzed by transposon tagging. We cloned three possible open reading frames (ORFs), designated hcuA, hcuB and hcuC, from the genomic DNA of P aeruginosa NCIMB9571 using the transposon insertion area of strain PARM1 as a DNA probe. Examination of the sequence revealed the transposon was inserted into hcuA. The full length of the hcuABC genes transformed into strain PARMI achieved 87% recovery of the desulfurization activity of DBT in n-TD, but partial hcuABC genes achieved only 0--12%. These results indicate that DBT desulfurization in the oil phase by recombinant P. aeruginosa strain NCIMB9571 requires the full length of the hcuABC gene cluster. The hcuABC gene cluster relates to DBT uptake from the oil phase to inside of the cell, and the uptake ability is independent of the n-alkane utilization ability, the biosurfactant production and the fatty acid composition of cells.
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