The Study of Biodesulfurization Activity in Recombinant E. coli Strain by Cloning the dsz Genes Involve in 4S Pathway

Several research groups have attempted to make recombinant bacteria capableof efficient desulfurization of oil fraction. the main aim of this study was todesign a recombinant strain in order to desulfurize dibenzothiophen (dbt) and itscomponents found in petroleum. in this study the pvlt31 vector harboringdszabc genes was transferred into recombinant e. coli bl21 which contained thedszd gene previously. we found that the recombinant e. coli bl21 containing thepvlt31 plasmid harboring dszabc genes and the pet21a plasmid harboringdszd gene had the highest capability for desulfurization of dibenzothiophen, whenthese four genes co-expressed. the data obtained in this study were confirmed byusing gibbs test, high-performance liquid chromatography (hplc) andmeasuring of dry cell weight. these analyses showed that dszabc and dszdgenes co-express under the heterologous promoter in the strains which are stablein oil and petroleum compounds. in the next step the puc18 plasmid harboringdszab genes of rhodococcous fmf was transferred into e. coli dh5á in order toevaluate the effect of elimination of dszc gene in the rate of biodesulfurizationprocess. this analysis demonstrated that 2-hydroxybiphenyl (2-hbp) productionof recombinant e. coli dh5á using broken 4s pathway was less than that ofrhodococcous fmf in comparison. in this report we showed that the existence ofthe third gene (dszc) is necessary for enhancement of desulfurization activity.