The effect of bacteria addition on DDT biodegradation by BROWN-ROT fungus Gloeophyllum trabeum

Abstract

DDT (1,1,1-trichloro-2,2 bis(4-chlorophenyl) ethane) is a synthetic insecticide that has several negative effects on the environment and humans. Therefore, determining an effective method to reduce DDT may give a beneficial impact. Brown-rot fungus, Gloeophyllum trabeum, is well known to have the ability to degrade DDT, even though it might require long-term remediation. In this study, the effect of the addition of bacteria on the biodegradation of DDT by G. trabeum had been investigated. Bacillus subtilis, Pseudomonas aeruginosa, and Ralstonia pickettii were screened for the bacteria which the volume of bacteria at 1, 3, 5, and 10 mL and the time range of addition of bacteria on days 0, 1, 3, and 5. The addition of B. subtilis, P. aeruginosa, and R. pickettii bacteria into the G. trabeum culture increased DDT biodegradation to approximately 62.02; 74.66; and 75.72%, respectively, in which G. trabeum was only able to degrade DDT by 54.52% for 7 days of incubation. R. pickettii enhanced the degradation process, in which the addition of 10 mL of this bacterium at day 1 possessed the highest value of 92.41% within 7 days of incubation. DDD was detected to be a product metabolite through a dechlorination reaction. This study indicated that mixed cultures of G. trabeum and R. pickettii can be used to degrade DDT.

Keywords

• Biodegradation
• DDT
• Bacillus subtilis
• Pseudomonas aeruginosa
• Ralstonia pickettii
• Gloeophyllum trabeum