title: Thermophilic biodesulfurization of hydrodesulfurized light gas oils by Mycobacterium phlei WU-F1.
abstract: Recalcitrant organosulfur compounds such as dibenzothiophene (DBT) derivatives in light gas oil (LGO) cannot be removed by conventional hydrodesulfurization (HDS) treatment using metallic catalysts. The thermophilic DBT-desulfurizing bacterium Mycobacterium phlei WU-F1 grew in a medium with hydrodesulfurized LGO as the sole source of sulfur, and exhibited high desulfurizing ability toward LGO between 30 and 50 degrees C. When WU-F1 was cultivated at 45 degrees C with B-LGO (390 ppm S), F-LGO (120 ppm S) or X-LGO (34 ppm S) as the sole source of sulfur, biodesulfurization resulted in around 60-70% reduction of sulfur content for all three types of hydrodesulfurized LGOs. In addition, when resting cells were incubated at 45 degrees C with hydrodesulfurized LGOs in the reaction mixtures containing 50% (v/v) oils, biodesulfurization reduced the sulfur content from 390 to 100 ppm S (B-LGO), from 120 to 42 ppm S (F-LGO) and from 34 to 15 ppm S (X-LGO). Gas chromatography analysis with an atomic emission detector revealed that the peaks of alkylated DBTs including 4-methyl-DBT, 4,6-dimethyl-DBT and 3,4,6-trimethyl-DBT significantly decreased after biodesulfurization. Therefore, thermophilic M. phlei WU-F1, which could effectively desulfurize HDS-treated LGOs over a wide temperature range up to 50 degrees C, may be a promising biocatalyst for practical biodesulfurization of diesel oil.
authors.affiliation: Department of Applied Chemistry, School of Science and Engineering, Waseda University, 3-4-1 Ohkubo, Shinjuku-ku, Tokyo 169-8555, Japan.
authors.forename: Toshiki
authors.initials: T
authors.lastname: Furuya
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Ishii
authors.forename: Ken-ichi
authors.initials: K
authors.lastname: Noda
authors.forename: Kuniki
authors.initials: K
authors.lastname: Kino
authors.forename: Kohtaro
authors.initials: K
authors.lastname: Kirimura
mesh_terms: D001673:Biodegradation, Environmental; D003470:Culture Media; D005742:Gasoline; D006358:Hot Temperature; D009168:Mycobacterium phlei / Q000254:growth & development / Q000378:metabolism*; D013455:Sulfur / Q000378:metabolism*; D013696:Temperature; D013876:Thiophenes / Q000378:metabolism
chemical_list: D003470:Culture Media; D005742:Gasoline; D013876:Thiophenes; D013455:Sulfur; C016366:dibenzothiophene