Effects of bacterium Ralstonia pickettii addition on DDT biodegradation by Daedalea dickinsii

DDT (4,4-Dichlorodiphenyltrichloroethane) is one of the persistent organic pollutants that was extensively used in the 1940s as insecticide to control malaria. Even though DDT was banned since 1970, DDT and its metabolites are still present ubiquitously in the environment and have negative effects on human health. In this study, the ability of brown-rot fungus (BRF) Daedalea dickinsii to degrade DDT with the addition of Ralstonia pickettii was investigated. R. pickettii was added into 10 mL of D. dickinsii culture at 1, 3, 5, 7 and 10 ml (1 mL ≈ 1.44 x 10¹³ bacteria cells). DDT recovery was analyzed by HPLC. The addition of 10 mL R. pickettii to D. dickinsii culture yielded the highest DDT degradation of about 68.62%. This result was higher than DDT degradation by D. dickinsii only (about 53.61%) and by 10 mL R. pickettii only 19.84%. This result indicated that the addition of 10 mL R. pickettii can enhance DDT degradation by D. dickinsii.