The oxidation of a number of bicyclic [n.2.0] ketones has been investigated using a novel bacterial isolate, Pseudomonas putida AS1. The organism was shown to promote similar Baeyer-Villiger type oxidations to the well-characterized organism, Acinetobacter sp. NCIMB 9871. A number of trends were noted with respect to the effect of different substitutions on the substrate on the regio- and stereoselectivity of the whole-cell-catalyzed reactions. These observations are of importance in defining the steric requirements for selectivity in cyclohexanone monooxygenase-catalyzed reactions. Pseudomonas putida AS1 is proposed as an alternative biocatalyst to the pathogenic Acinetobacter species.