The naphthalene degradation pathway is organized into two oper- ons: the upper pathway includes 6 protein coding genes for the trans- formation of naphthalene to salicylate; the lower pathway involves 11 protein coding genes for the meta cleavage of salicylate through cate- chol leading to metabolic intermediates, as depicted in Fig. 4. In strain 19SMN4T, these 20 genes were located in plasmid pLIB119, as dis- cussed later. In strain ST27MN3, these genes were located in the chromosome.