Cloning and expression of SOX (dsz A, B, C) operon in E.coli strain DH5α and comparison its desulfurization activity with Pesudomonas aeroginosa EGSOX, Pesudomonas putida EGSOX and E.coli cc118λpir

The combustion of sulfur-containing fossil fuels is a source of environmental pollution. During previous decades, desulfurization of fossil fuels has been considered as a cost-effective and alternative friendly environmental approach. DBT has been widely used as a model compound to screen microorganisms ability for desulfurization. There are several reports on the isolation of DBT-desulfurizing bacteria. In this respect, Rhodococus erythropolis IGTS8 has an desulfurization operon (dsz A,B,C), which can convert DBT, as a source of sulfur, to 2HBP via the 4s pathway. In this study, the (dsz A,B,C) operon was cloned into the PVLT31 plasmid and then transformed into the E.coli DH5α. Plasmid purification was performed using mini prep and analysied by PCR technique and restriction endonuclease. Desulfurization activity was measured and compared between the recombinant and Rhodococus erythropolis IGTS8, Pesudomonas aeroginosa EGSOX, Pesudomonas putida EGSOX and E.coli cc118λpir by Gibb,s assay and HPLC. Maximum 2HBP production was detected in Pesudomonas aeroginosa EGSOX and E.coli DH5α, respectively. Specific activity for desulfurization of DBT is boosted by increasing the copy number of (dsz A,B,C) operon and sulfur repression can be alleviated by promoter replacement