Bioremediation of Xenobiotic Pesticides by Bacterial Species Isolated from Flower Farm Soil around Lake Naivasha, Kenya

Abstract

This study reports isolation and identification of bacterial species from flower farm soils capable of biodegrading xenobiotic pesticides commonly used in flower farms. Soil samples were collected from randomly selected from five major flower farms around Lake Naivasha basin. Four sampling points for each greenhouse within the farms were randomly selected i.e., two points within the greenhouses and two water drainage points around the greenhouses. Morphological, cultural and biochemical characterization of bacterial species isolated from the flower farm soil samples identified mainly Pseudomonas aeruginosa, Escherichia coli, Rhodococcus erythropolis and Bacillus subtilis species. Qualitative and quantitative analysis of soil samples by High Pressure Liquid Chromatography identified aldrin, dieldrin, endosulfan, dimethoate, malathion and methyl parathion as the main pesticide residues present. The bacterial isolates were grown in nutrient media and incubated with different concentration of pesticide residues depending on the mean concentration of the pesticide residues analyzed from soil samples. Analysis for biodegradation of pesticide consortia was done every 2 days, 10 days, 15 days and 21 days at 15°C in vitro. All the bacterial species were capable of degrading the pesticide residues at different level. Bioremediation can therefore be better alternative in solving pollution problems around lake Naivasha basin. The bioremediation products were identified by High Performance Liquid Chromatography.