Isolation, Characterization, and Biodegradation Potential of Bacillus Species on Selected Pesticides in Agricultural Soils of Enugu State, Nigeria

Abstract

This study investigates the isolation, characterization, and evaluation of Bacillus species in the biodegradation of selected pesticides. Soil samples were collected from agricultural farmlands in Amechi and Agbani, Enugu State, Nigeria, where pesticide application is a common practice. The pesticides used in this study include Ridoff (organophosphate-based) and Lara Force (pyrethroid based). Microorganisms capable of utilizing these pesticides were isolated using mineral salt medium and further identified through biochemical characterization techniques such as Gram staining, motility test, spore staining, catalase, oxidase, and indole tests. The results revealed that the dominant isolates were Bacillus subtilis and Bacillus licheniformis. These isolates demonstrated significant potential in degrading both pesticides over a 21-day incubation period. Degradation efficiency was assessed using spectrophotometric analysis and colony count methods. Lara Force showed a higher degradation rate compared to Ridoff, with values ranging from 0.336 to 1.848, while Ridoff recorded values between 0.600 and 1.731. Environmental factors such as temperature and incubation time influenced degradation efficiency. The findings of this study highlight the effectiveness of Bacillus species in the biodegradation of pesticide residues, suggesting their potential application in bioremediation strategies for contaminated agricultural soils. This approach offers an ecofriendly and cost-effective alternative to chemical methods of pollution control.