EFFECT OF SELECTED ENVIRONMENTAL-FACTORS ON DEGRADATION AND MINERALIZATION OF BIARYL COMPOUNDS BY THE BACTERIUM RALSTONIA-PICKETII IN SOIL AND COMPOST

By varying selected environmental factors, the degradation and mineral ization of biaryl compounds by the bacterium Ralstonia pickettii in so il and compost were investigated. An optimized soil moisture and enhan ced bioavailability by using the nonionic surfactant Tween 80 were of great importance for the degradation rates of biaryl compounds like bi phenyl and 4-chlorobiphenyl by cells of Ralstonia picketti SBUG 290 in oculated into soil. Additionally, degradation of these compounds by th e investigated strain in soil was strongly dependent upon the medium o f precultivation. Also the influence of temperature and soil pH-value was tested. In contrast to the used soil, the autochthonous flora of t he compost seemed to have a higher physiological activity. All investi gated compounds (biphenyl, 4-chlorobiphenyl and dibenzofuran) were deg raded quickly in compost. Inoculation with the investigated bacterium did not enhance the degradation rates significantly. (C) 1998 Elsevier Science Ltd. All rights reserved.