Biological desulfurization, also known as biocatalytic desulfurization (BDS), is a new technology to remove bound sulfur from sulfur-containing heterocyclic compounds in petroleum by aerobic and anaerobic bacteria at normal temperature and pressure. As early as 1948, there was a patent for biological desulfurization in the United States, but there was no successful example of hydrocarbon sulfide removal, mainly because the role of bacteria could not be effectively controlled. Since then, there have been several successful reports of "microbial desulfurization", but the application value is not great, because although microorganisms remove sulfur from oil, they also consume a lot of carbon in oil and reduce a lot of heat release in oil [9]. Scientists have been doing in-depth research on dibenzothiophene until 1998, when researchers from American Institute of Gas Technology (IGT) successfully isolated two special strains, which can selectively remove sulfur from dibenzothiophene, and successively produced industrial models for removing heterocyclic sulfur molecules from oil products. 1992 applied for two patents in the United States (5002888 and 56544) respectively. American Energy Biosystems Corporation (EBC) obtained the right to use these two strains. On this basis, the company not only successfully produced and regenerated the biological desulfurization catalyst, but also reduced the production cost and prolonged its service life. In addition, the company also isolated Rhodococcus maydis, which can break the C-S bond and achieve the purpose of not losing petroleum hydrocarbons during desulfurization [10]. Now, EBC has become the most widely researched company in the world for biological desulfurization technology. In addition, the Institute of Life Engineering Industry Technology of Japan Industrial Technology Research Institute and the Petroleum Industry Activation Center jointly developed a new strain for diesel desulfurization, which can simultaneously remove the sulfur in dibenzothiophene and benzothiophene in diesel, but the sulfur in these two sulfides is difficult to remove by other methods [1 1].
BDS process is an oxidation reaction between aerobic bacteria and organic sulfide produced in nature. Selective oxidation breaks the C-S bond, oxidizes the sulfur atom into sulfate or sulfite and transfers it to the water phase, while the skeleton structure of DBT is oxidized into hydroxybiphenyl and remains in the oil phase, thus achieving the purpose of removing sulfide. BDS technology has been developed for decades since its appearance, and it is still in the stage of development and research. Because BDS technology has many advantages, it can be organically combined with existing HDS devices, which can not only greatly reduce the production cost, but also have stronger economic competitiveness than HDS because of the high added value of organic sulfur products. At the same time, BDS can also be combined with catalytic adsorption desulfurization, which is an effective method to realize deep desulfurization of fuel oil. Therefore, BDS technology has a broad application prospect, and it is predicted that industrial devices will appear around 20 10.