Improvement of desulfurization activity in Rhodococcus erythropolis KA2-5-1 by genetic engineering

Rhodococcus erythropolis KA2-5-1 can desulfurize dibenzothiophene (DBT) int o 2-hydroxybiphenyl. A cryptic plasmid, pRC4, which was derived from R. rho dochrous IFO3338, was combined with an Escherichia coil vector to construct an E. coli-Rhodococcus shuttle vector. The complete nucleotide sequence of 2582-bp pRC4 was analyzed. Based on the characteristics of its putative re plication genes, pRC4 was assigned to the family of pAL5000-related replico ns. The desulfurization gene cluster, dszABC, and the related reductase gen e, dszD, cloned from KA2-5-1, were reintroduced into KA2-5-1 and efficientl y expressed. The DBT desulfurization ability of the transformant carrying t wo dszABC clusters and one dszD on the vector was about ii-fold higher than that of the parent strain, and the transformant also showed improved desul furization activity for light gas oil (LGO). Sulfur components in LGO befor e and after the reaction were analyzed with gas chromatography-atomic emiss ion detection.