DDT Resistance and Transformation by Different Microbial Strains Isolated from DDT-Contaminated Soils and Compost Materials

• Published in: Compost science & utilization Vol. 11; no. 4; pp. 300 - 310
• Main Authors: Kantachote, D, Singleton, I, McClure, N, Naidu, R, Megharaj, M, Harch, B.D
• Format: Journal Article
• Language: English
• Published: Emmaus,PA Taylor & Francis 01.09.2003; JG Press; Taylor & Francis Ltd
• Subjects: Agronomy. Soil science and plant productions; Bacillus; Bacillus (bacteria); bacteria; Biological and medical sciences; bioremediation; composts; DDD (pesticide); DDE (pesticide); DDT (pesticide); ethane; ethylene; Fundamental and applied biological sciences. Psychology; fungi; General agronomy. Plant production; metabolites; Other nutrients. Amendments. Solid and liquid wastes. Sludges and slurries; soil; Soil-plant relationships. Soil fertility. Fertilization. Amendments; temperature; Resistance; Compost; Soil pollution; DDT; Waste reuse
• ISSN: 1065-657X; 2326-2397
• DOI: 10.1080/1065657X.2003.10702139

Bioremediation is a potential option to treat 1, 1, 1-trichloro-2, 2-bis (4-chlorophenyl) ethane (DDT) contaminated sites. In areas where suitable microbes are not present, the use of DDT resistant microbial inoculants may be necessary. It is vital that such inoculants do not produce recalcitrant breakdown products e.g. 1, 1-dichloro-2, 2-bis (4-chlorophenyl) ethylene (DDE). Therefore, this work aimed to screen DDT-contaminated soil and compost materials for the presence of DDT-resistant microbes for use as potential inoculants. Four compost amended soils, contaminated with different concentrations of DDT, were used to isolate DDT-resistant microbes in media containing 150 mg l[sup-1] DDT at three temperatures (25, 37 and 55 Celsius). In all soils, bacteria were more sensitive to DDT than actinomycetes and fungi. Bacteria isolated at 55 Celsius from any source were the most DDT sensitive. However DDT-resistant bacterial strains showed more promise in degrading DDT than isolated fungal strains, as 1, 1-dichloro 2, 2-bis (4-chlorophenyl) ethane (DDD) was a major bacterial transformation product, while fungi tended to produce more DDE. Further studies on selected bacterial isolates found that the most promising bacterial strain (Bacillus sp. BHD-4) could remove 51% of DDT from liquid culture after 7 days growth. Of the amount transformed, 6% was found as DDD and 3% as DDE suggesting that further transformation of DDT and its metabolites occurred.