Heavy gas oil biodesulfurization using a low-cost bacterial consortium

Abstract

BACKGROUND: Petroleum and its derivatives usually contain large amounts of sulfur. During the combustion of fossil fuels, sulfur is liberated to the atmosphere in the form of one of the most noxious pollutants: sulfur dioxide (SOx). The removal of sulfur content to the ultralow levels demanded by worldwide legislation has been a challenge to the refinery industry, principally due to the inefficiency of conventional processes, such as hydrodesulfurization, which are not capable of removing the recalcitrant sulfur compounds. Biodesulfurization is a biological process that removes these sulfur compound pollutants from hydrocarbons. However, there are several unsolved technological difficulties associated with this procedure, including the development of a stable and efficient biocatalyst, and a low-cost culture medium. Thus, the use of a bacterial consortium (BC) as a substitute for both biocatalyst and nutritional medium was studied in order to improve the biodesulfurization process. RESULTS: The desulfurization activity was determined at different temperatures and BC concentrations. An efficient desulfurization capacity (71.2%) was observed using only 5% (w/w) of BC at 45 °C. At this temperature, the total time required for biodesulfurization was substantially reduced; only 2 h was required to achieve the highest desulfurization capacity. CONCLUSION: The BC can be used as a substitute for biocatalysts and nutritional media for heavy gas oil desulfurization. Desulfurization capacity using the BC was similar to that achieved using other pure bacterial strains and culture media, and the process time was diminished. BC use represents an important improvement in biodesulfurization technology. © 2018 Society of Chemical Industry.