TITLE Development of microbiological treatment technology for xenobiotic compounds
(Joint Program to Promote Technological Development with the Private Sectors)



Environmental pollution with hazardous xenobiotic compounds, such as polycyclic aromatic hydrocarbons, chlorinated organic compounds, dioxins, and endocrine disrupting chemicals has lately attracted considerable attention. Biological treatment processes using microorganisms are expected to be methods for the treatment of these hazardous substances, because they are commonly low-energy consuming and environment-friendly processes in comparison with physical and chemical treatment processes. Bacteria such as Pseudomonas sp. and Sphingomonas sp. and white-rot fungi (WRF) such as Phanerochaete sp. can degrade xenobiotic compounds. WRF have superior ability to bacteria in degradation of a wide variety of xenobiotic compounds, and the degrading system of these fungi is rather non-specific in manner. In this project, we aimed to develop an efficient treatment process using WRF for effluent and groundwater polluted with hazardous xenobiotic compounds. In fiscal 1998, we obtained a novel WRF, named LSB-69, which has great degrading ability to xenobiotic compounds from nature sources. In fiscal 1999, we tried to improve the breed of LSB-69 by mutation treatment and screening, and LSB-69-31, which has superior degrading ability to the original strain LSB-69 was obtained. In fiscal 2000, the main purpose was to develop an efficient bioreactor system using LSB-69-31 to clean-up wastewater polluted with hazardous xenobiotic compounds. Continuous treatment tests of the model polluted water (pentachlorophenol solution) with five bioreactors, which were the air-lifted mixed bioreactor, the up-flowed fixed bed bioreactor, the sprinkled fixed bed bioreactor, the rotated disk bioreactor, and the soaked membrane bioreactor were performed, and the pentachlorophenol removal efficiency of each bioreactor was evaluated. The rotated disk bioreactor showed the best performance among the five bioreactors. In conclusion, we could develop the efficient biological process using the WRF to clean-u p wastewater polluted with hazardous xenobiotic compounds in this project.