Biodegradation of thiophene by cometabolism in a biofilm system

An investigation of the cometabolic degradation of thiophene in the presence of benzene has been performed in a continuous biofilm system in order to study the kinetics of this conversion. The study showed result that thiophene interferes with the metabolism of benzene: benzene is not completely mineralised in the presence of thiophene. The micro-organisms are inactivated by thiophene, its metabolites or the metabolites of benzene. For low ratios of thiophene to benzene in the inlet of the reactor, the bacteria seem to adapt to thiophene and regain part of their activity that was lost when thiophene was introduced in the system. A hypothesis for this phenomena is that toxic metabolites of thiophene are converted biologically or abiotically into compounds, which are less harmful and inhibiting to the micro-organisms. Resting cells, which have been activated previously with benzene, are able to degrade thiophene, and this conversion leads to the inactivation or the death of the cells.