Isolation and Characterization of Dichlorodiphenyltrichloroethane (DDT) Degrading Fungi Isolated from Agro-Industrial Effluent and Farm Soils
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Date
2025-02
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Addis Ababa University
Abstract
Dichlorodiphenyltrichloroethane (DDT) is an environmentally hazardous synthetic compound that
is resistant to usage. Despite being illegal in most countries, it is used as a pesticide to fight malaria
in most malarial zone part of Ethiopia. The main objective of this study is to screen, characterize,
and evaluate potential DDT-degrading fungi and their synergetic interaction effects for
mycoremediation purposes. The composite of 150 soil and effluent samples was collected from
Addis Ababa and East Shewa Zone, mainly Ziway and Koka. Fungal isolation and screening were
performed using a serial dilution on potato dextrose agar growth media. MALDI-TOF MS
technology was used for fungal identification. Fungal biomass production and sporulation capacity
were examined and optimized using a Box-Behnken experimental design. The potential DDTtolerant
fungi were studied based on growth factor optimization. Gas Chromatograph-Electron
Capture Detector technology was used for the DDT degradation study. Fungal identification results
revealed that the finally selected isolates, AS1 and T1, were Asppergillus niger and Trichoderma
koningii, respectively. The optimization results confirmed that the co-inoculated isolates AS1T1
had a maximum biomass (1.01±0.16 g) and spore count (5.74±0.37 log spore/mL) and were
selected as possible DDT-degrading fungi. The GC-ECD result analysis revealed that fungal-cocultured
A. niger and T. koningii in DDT-amended liquid medium were able to degrade DDT into
its metabolites Dichlorodiphenyldichloroethane (DDD) and Dichlorodiphenyldichloroethylene
(DDE). The results also revealed that 99.5–99.99% of DDT and its metabolites degraded from
initial concentrations of 1750, 3500, 5250, and 7000 ppm. The co-inoculated fungi A. niger and T.
koningii are promising candidates for the removal of DDT and its metabolites from polluted
environments.
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Keywords
Dichlorodiphenyldichloroethane, Dichlorodiphenyldichloroethylene, Dichlorodiphenyltrichloroethane, Degradation, Gas Chromatography-Electron Captured Detector, Matrix-Assisted Laser Desorption, Ionization, Optimization