Bioremediation characteristics, influencing factors of dichlorodiphenyltrichloroethane (DDT) removal by using nonindigenous Paracoccus sp.

The marine bacterium able to consume DDT as the nutrient source was isolated from sea water which was identified as Paracoccus sp. DDT-21 based on 16 S rDNA gene sequence and Gram negative rod, obligate aerobic, non-motile biochemical characteristics. The isolate can degrade over 80% of the DDT, at a concentration of 50 mg/L in MSM in 72 h. Time and pollutant (DDT) dependent growth studies indicated that the isolate Paracoccus sp., DDT-21 significantly degrade the DDT and tolerates under DDT stress up to 50 mg/L. The DDT degradation capability of the strain Paracoccus sp. DDT-21 was found to be 5 (>) 10 (>) 15 (>) 25 (>) 50 mg/L DDT. The high concentrations (75 and 100 mg/L) of DDT showed significant decrease in DDT degradation. The optimal DDT degradation (similar to 90.0%) was observed at 6 g/L of yeast extract, 6% of glucose in pH 7.0 at 35 degrees C with 72 h of incubation as constant. Furthermore, four metabolites were observed by GC-MS analysis such as, DDE, DDD, DDMU, and DDA. The obtained results indicate that the isolate Paracoccus sp. DDT-21 is a promising candidate for the removal and/or detoxification of DDT in the environment. (C) 2020 Elsevier Ltd. All rights reserved.

Automated summary

Paracoccus sp. DDT-21, isolated from sea water, is able to degrade over 80% of DDT at 50mg/L concentration in 72 hours, and shows tolerance to DDT stress. The optimal conditions for DDT degradation by this strain include pH 7.0, 35 degrees C, 6g/L yeast extract, and 6% glucose, with a degradation rate of approximately 90%.