Investigation and Application of a Novel Pseudomonas aeruginosa (KIBGE-AB9) for the Biodegradation of Malathion in Agriculture Soil

Abstract

Malathion, an organophosphate insecticide despite its significant benefits in agricultural productivity, is an important pollutant and food contaminant which affects the non-target species. This research aimed at finding biological control strategies to degrade malathion in the agriculture soil. For this purpose, soil samples were collected from different agricultural areas known for malathion application continuously from the past five years. The isolated bacterial communities were subjected to identification, characterization and malathion degrading genes. Growth kinetics of bacterial strains at different environmental conditions (pH, temperature and malathion concentration) were performed. An isolate identified as Pseudomonas aeruginosa, based on morphological, biochemical and 16S rRNA gene sequencing analysis, showed ability to successfully degrade malathion as assessed by semi-quantitative pesticide hydrolysis test. Optimal degradation activity was observed at pH 7.0, soil temperature 37°C and malathion contents of 100 mg.kg-1. The isolated strains of P. aeruginosa were found to possess organophosphate hydrolase encoding gene (ophB), suggesting that bacterial strain uses malathion as carbon source. Bioremediation of malathion by P. aeruginosa could be a promising approach against pesticide contamination in agriculture soil.