Biodegradability and biodegradation pathways of chlorinated cyclodiene insecticides by soil fungi

Area of Science:

• Environmental Microbiology
• Bioremediation
• Fungal Metabolism

Background:

• Organochlorine pesticides, such as dieldrin and endosulfan, pose significant environmental risks due to their persistence and toxicity.
• Isolation of effective microbial degraders is crucial for developing sustainable bioremediation strategies.

Purpose of the Study:

• To isolate and characterize aerobic fungi capable of degrading dieldrin and endosulfan from contaminated soil.
• To investigate the degradation pathways and metabolic products of these fungi when exposed to specific organochlorine pesticides.

Main Methods:

• Isolation of fungal strains from pesticide-contaminated soil.
• Incubation of fungal strains with dieldrin and endosulfan under controlled aerobic conditions (25°C).
• Analysis of degradation percentages and identification of metabolites using analytical techniques.

Main Results:

• Mucor racemosus strain DDF efficiently degraded over 90% of dieldrin in 10 days, producing aldrin trans-diol and its phosphorylated derivatives.
• Mortierella sp. strains W8 and Cm1-45 degraded over 70% and 50% of α and β-endosulfan, respectively, in 28 days.
• Endosulfan degradation by Mortierella sp. involved the formation of endosulfan diol and endosulfan lactone, with minimal production of persistent endosulfan sulfate.

Conclusions:

• Mucor racemosus and Mortierella sp. demonstrate significant potential for the bioremediation of dieldrin and endosulfan contaminated environments.
• Understanding the specific metabolic pathways provides insights for optimizing fungal-based degradation processes.