Selective cleavage of the two CS bonds in asymmetrically alkylated dibenzothiophenes by Rhodococcus erythropolis KA2-5-1

• Published in: Journal of bioscience and bioengineering 2001-01, Vol.92 (1), p.80-82
• Main Authors: Onaka, Toshimitsu, Kobayashi, Morio, Ishii, Yoshitaka, Konishi, Jin, Maruhashi, Kenji
• Format: Article
• Language: English
• Subjects: asymmetrically alkylated dibenzothiophenes; BIODEGRADATION; Biological and medical sciences; Biology of microorganisms of confirmed or potential industrial interest; Biotechnology; carbon-sulfur-bond-targeted cleavage; desulfurization; Fundamental and applied biological sciences. Psychology; HETEROCYCLIC COMPOUNDS; Miscellaneous; Mission oriented research; ORGANOSULPHUR COMPOUNDS; RHODOCOCCUS (BACTERIA); Rhodococcus erythropolis
• ISSN: 1389-1723; 1347-4421
• DOI: 10.1016/S1389-1723(01)80204-8

The Rhodococcus erythropolis strain KA2-5-1 was characterized by its ability to cleave carbon-sulfur bonds in the dibenzothiophene (DBT) ring by asymmetrically alkyl substitution, such as C 2-DBTs ( e.g., dimethyl and ethyl DBTs) and C 3-DBTs ( e.g., trimethyl and propyl DBTs), which are known to remain in hydrodesulfurization-treated diesel fuels. After treatment by solid-phase extraction (SPE) of solvents from microbial reactions of alkylated DBTs (Cx-DBTs), we used gas chromatography (GC), GC-atomic emission detection, GC-mass spectrometry and 1H nuclear magnetic resonance spectroscopy to identify and quantitatively evaluate the Cx-DBT metabolites. Molar ratios of metabolic isomers of the desulfurization products suggested that resting-cell reactions of KA2-5-1 against these Cx-DBTs occurrs through specific carbon-sulfur-bond-targeted cleavages, yielding alkylated hydroxybiphenyls, and that the manner of the attack on the DBT skeleton is affected not only by the position but also by the number and length of the alkyl substituents.