Evaluation of toluene degradation pathways by two-dimensional stable isotope fractionation.

Toluene degradation by several pure and mixed microbial cultures was investigated bytwo-dimensional compound specific isotope analysis (2D-CSIA). For most of the cultures, the respective toluene degradation pathway and toluene attacking enzymatic step was known. The slope of the linear regression for hydrogen (delta delta(2)H) vs.

Combined carbon and hydrogen isotope fractionation investigations for elucidating benzene biodegradation pathways.

Recently, combined carbon and hydrogen isotope fractionation investigations have emerged as a powerful tool for the characterization of reaction mechanisms relevant for the removal of organic pollutants. Here, we applied this approach in order to differentiate benzene biodegradation pathways under oxic and anoxic conditions in laboratory experiments. Carbon and hydrogen isotope fractionation of benzene was studied with four different aerobic strains using a monooxygenase or a dioxygenase for the initial benzene attack, a facultative anaerobic chlorate-reducing strain as well as a sulfate-reducing mixed culture.