Characterization of the biochemistry and physiology of hydrocarbon degradation pathways by stable isotope approaches

Biodegradation plays an important role in the removal of hydrocarbons from the environment. Compared to the extensive studies concerning aerobic hydrocarbon degradation, there is still a lack of knowledge with regard to the degradation of hydrocarbons under anoxic conditions. The current thesis, containing three subprojects, focused on the anaerobic degradation of the BTEX (abbreviation for benzene, toluene, ethylbenzene, xylene) compound - especially ethylbenzene, n-alkanes and phenols. Phenols are close relatives of BTEX compounds; the biodegradation pathways of phenols and BTEX share many similarities with regard to the activation mechanisms and the enzymes involved. Stable isotope analysis was applied in this thesis as the main tool for the characterization of hydrocarbon degradation pathways and involved microorganisms. The carbon or hydrogen stable isotope fractionation patterns upon biodegradation of TEX, n-alkanes and phenols were determined to elucidate the degradation pathways. Carbon stable isotope labelling method was applied to identify the key-players in an ethylbenzene-degrading enrichment culture. ...