A model simulating bacterial degradation of LAS detergents was devised by employing simpler compounds, benzene sulfonate and p-toluene sulfonate, as the sole sources of carbon and sulfur. This substitution permitted observation of alkylarylsulfonate oxidation by a single species of bacteria, identified as Pseudomonas testosteroni. The recorded features of the biodegradation process included effect of substrates and buffers, growth kinetics, cells' respiratory activity, and the influence of inhibitors. Results suggested that catechol or corresponding alkyl derivatives form intermediate products, and that the reaction involves participation of at least one enzyme, catechol-2,3-dioxygenase. Oxidation of catechol via a meta cleavage enzyme has been demonstrated with whole cells, as well as cell-free extracts. Biodegradation of linear alkylate sulfonate detergents was achieved only with mixed bacterial cultures. (Wilde-Wisconsin)