The collection of papers is the result of the first year's results of the Project: METABOLISM AND MOLECULAR SYSTEMS FOR THE BIOTRANSFORMATION OF AROMATIC MOLECULES. Aim of the research project is to gain knowledge in microorganisms endowed with the ability of transforming aromatic compounds, and in the genes and enzymes involved in this process. Particular attention is paid to the information acquired for its use in the development of biosynthetic systems for bioremediation and bioconversions. The pathways responsible for the aerobic catabolism of aromatic molecules are generally made up of an upper pathway, where hydroxylation reactions leading to the formation of hydroxylated intermediates occur, and a lower pathway where the aromatic ring of these dihydroxylated molecules are cleaved, and eventually converted, after several enzymatic steps, into intermediates of the Krebs cycle. It goes without saying that the great potential of these systems is related to the acquisition of information about the enzymatic systems involved and the regulation of their corresponding genes. The utilization of these micro-organisms can be expanded and improved by: (i) characterizing new microorganisms and their enzymatic systems to sort out a wide panel of enzymatic systems endowed with different metabolic abilities and different specificity, (ii) elucidating the transcriptional regulation and the molecular determinants responsible for the enzymatic activities in systems that are already known and in those that will be available during the development of the project. Moreover, in order to evaluate the influence of the information gained in developing processes it will be necessary to (iii) validate the development of a small number of applications. More specifically these goals have been achieved through: 1) Isolation and characterization of new bacterial strains either by isolation from polluted sites or by spotting new ones through the analysis of annotated genomes for identifying both new microorganisms and new enzymatic activities with enhanced catalytic biodegradative properties; 2) identification and analysis of the molecular determinants of the specificity of enzymatic systems either already available or new ones which will be available during the development of the project; 3) investigation of the transcription regulative systems involved in the expression of the enzymatic systems (in particular key enzymes in the metabolism of aromatic compounds) in both psychrophilic and mesophilic bacteria; 4) utilization of the results obtained from the different approaches above to set-up new biocatalysts for the bioremediation of model wastewaters and for the biosynthesis of compounds of pharmaceutical and industrial interest.