Biodesulfurization(BDS) is a promising technology for deep desulfurization.In this work,Pseudomo-nas delafieldii R-8 cells are immobilized in calcium alginate beads and used for BDS of transportation fuels.It is found that thiophene and dibenzothiophene(DBT) can be simultaneously metabolized by immobilized R-8 cells.The initial sulfur content in the model oil is 300 mg?kg?1(thiophene︰DBT 1︰1).After 10 h of treatment,the thiophene concentration is reduced by 40%,while DBT is reduced by 25%.The utilization rate of thiophene is faster than that of DBT.Moreover,the oil/water ratio of alginate immobilized cells is studied to reduce the water volume in desulfurization systems.Long-term recycling of BDS by alginate immobilized cells is carried out with oil/water ratio at 5︰1.The immobilized cells are successfully reused over 15 batch cycles.In the last batch,the desulfurization activity remains at least 75% of the first batch.
