Dioxins are environmental contaminants of global concern. Produced from combustion and as industrial synthesis byproducts, dioxins are ubiquitous in the environment. They are also toxic, carcinogenic and highly persistent. Bioremediation is an attractive method for dioxin removal because it is lower cost and less invasive than chemical or physical treatments. However, although many potential dioxin bioremediation agents have been examined, few have been identified that can remove 2,3,7,8-tetrachloro-dibenzo-p-dioxin (2,3,7,8-tetraCDD), the most toxic form of dioxin, or indeed most of the higher chlorinated dioxins. Sphingomonas wittichii RW1 is a bacterium with the ability to transform dioxins into less toxic chemicals, but it has not been observed to degrade 2,3,7,8-tetraCDD. This project aimed to improve upon the potential of this organism using site-directed mutagenesis. We were able to generate five variants that may prove to degrade 2,3,7,8-tetraCDD. This project brought together experts on Sphingomonas wittichii RW1 working in the United States and experts on genetic manipulation working in Japan to develop these variants with great promise for the transformation of dioxins. It therefore fostered international collaboration on an issue of international importance. It also enhanced the infrastructure for research partnerships by bringing together researchers from previously disparate groups. As part of this project, the principal investigator was able to travel to the Toyama Prefectural University in Japan. A large portion of dioxin research is taking place in Japan. It is therefore essential to collaborate with groups in Japan. This project initiated a new investigation in the area of dioxin research and a new collaboration between groups in the United States and Japan.