Identification of Carbofuran and Paraquat Degrading Microorganisms from Soil

Introduction: Increased rates of pesticide misapplication and follow-on concerns on public health have become subjects of countless distress. The occurrence of pesticides in soils could result in modifications in soil physical, chemical as well as biological properties hence the need for ways to reduce such impacts.

Research Gap: Insufficient literatures on extensive identification of pesticides’ degraders from non-impacted soils. Existing literatures are restricted to a particular microbial group (bacteria or fungi).

Aim: The study aimed at isolating, characterizing and testing bacteria, moulds, yeasts and actinomyces from soil for the biodegradation of pesticides.

Place and Duration of Study: The study was carried out at the Department of Environmental Management and Toxicology, Federal University of Petroleum Resources, Effurun and Federal Institute of Industrial Research, Oshodi, Lagos, Nigeria/ four months.

Methodology: Carbofuran and Paraquat degrading microorganisms were isolated from a non-pesticides impacted soil using mineral salt medium (MSM). The MSM composed in grams per liter: K2HPO4, 4.8; KH2PO4, 1.2; NH4NO3, 1.0; MgSO4 7H2O, 0.2; Ca(NO3)2 .4H20, 0.4, and Fe(SO4)3, 0.001 supplemented with 2 mM Carbofuran or Paraquat as the only carbon source. The ability of the microbial isolates to utilize Carbofuran and Paraquat was screened on MSM containing 150 part per million of the pesticides as the only carbon source. The isolates were identified using the analytical profile index (API), microscopic and macroscopic characteristics.

Results: Bacterial species identified were Bacillus, Pseudomonas, Kocuria, Enterobacter, Chryseobacterium, Corynebacterium, Acinetobacter, Paenibacillus, Lerclercia and Proteus. Actinomyces were Actinomyces isrealii, Actinomyces naeslundi, Actinomyces viscosus 1, Actinomyces meyeri and Actinomyces viscosus 2. Yeast isolates were Candida stellatoidea, Candida krusei and Saccharomyces cerevisiae while moulds were Talaromyces, Cladosporium carionii and Curvularia species.

Conclusion: These findings indicated that Carbofuran and Paraquat degrading organisms are readily extant in soils and can be used to facilitate the removal of these pesticides from such polluted environments.