Primary target compounds for biodegradation researches in our laboratory are endocrine destruction compounds (EDC), personal care products (PCP), and diverse pesticides. For the biodegradation researches, aerobic bacteria isolated from soils and water have been applied for the degradation of those compounds. As you see in Fig. 1, there have been known to be several aerobic metabolic pathways degrading simple aromatic toluene, including the pathway catalyzed by toluene dioxygenase. Toluene dioxygenase produces toluene cis-diol from toluene under the aerobic conditions. This biological oxidation process is somehow similar to Advanced Oxidation Process (AOP) known in Environmental Engineering Processes.

If we use this enzyme system with P450 camphor monooxygenase in the same bacterium, we can degrade pentachloroethane and trichloroethene sequentially under anaerobic and aerobic conditions (Fig. 2). In addition, thorough understanding of metabolism makes you unexpected lucky as you shown in Fig. 3. Toluene cis-diol, which cannot be produced by chemical methods in easy, has been applied for many different synthetic processes. Therefore, as exemplified here, it would be possible to create artificial pathways in bacteria able to degrade or produce chemicals of interest.

Fig. 1 Aerobic Bacterial Pathways of Toluene: an example of diverse metabolic pathways evolved in different bacterial species

Fig. 2 Application of toluene dioxygenase and P450 camphor monooxygenase to degrade solvents halogenated aliphatics by the recombinant P. putida G786 (pHG-2)

Fig. 3 Application of toluene dioxygenase to produce a valuable chemical synthon toluene cis-diol from toluene by the recombinant Burkholderia cepacia G4 (pHG-2)