A review on biodesulfurization of crude oil using different microorganisms: Reaction mechanisms, effective factors, and removal efficiency of organic sulfur compounds

Thiophene, benzothiophene and dibenzothiophene are the main organic sulfur compounds in crude oil, which reduce the quality of crude oil. Previous studies have shown that biodesulfurization (BDS) is the most efficient method for the separation of complex organic sulfur compounds from crude oil. BDS is performed at ambient pressure and temperature with excellent selectivity, leading to reduced energy cost, low emissions of CO₂ and lack of production of unfavorable by-products. In this review study, the advantages and disadvantages of BDS compared to other processes, the performance of various microorganisms in the removal of complex sulfur compounds, environmental impacts, and biodesulfurization kinetics were thoroughly discussed. Also, different mechanisms of biodesulfurization process and their pathways in removing sulfur compounds were investigated. Moreover, the utilization of genetic engineering to improve biodesulfurization efficiency was studied. According to previous studies, the Bintulu oil field in Malaysia and the Boscan oil field in Venezuela have the lowest (0.03 %) and the highest sulfur content (5.7 %), respectively. Also, some microorganisms such as Mycobacterium goodie X7B, Rhodococcus erythropolis XP, Rhodococcus sp. ECRD-1, and Gordonia alkanivorans have shown significant biodesulfurization efficiency. In general, the integration of BDS and hydrodesulfurization processes is recommended as an efficient and environmentally friendly process in removing complex sulfur compounds.