Characterization of soil bacteria capable of degrading selected organic pesticides applied in horticultural farms in Kenya

Pesticide use has been one of the major factors in improving productivity in agricultural enterprises. Pesticide residues in food and drinking water when ingested affect human health while ecosystems are also affected through loss of biodiversity. The aim of the research was to survey pesticide usage in farms under horticultural production, isolate bacterial strains, evaluate their biodegradation potential of selected pesticides, characterize the bacteria isolates morphologically, biochemically and molecularly. A survey in four horticultural regions of central and rift-valley Kenya showed that out of the twenty two (22) formulations of organophosphorus pesticides used by farmers diazinon had the highest proportion of application at 45.9%., followed by dimekill at 18.9% and least in application was brigade at 5.5%. Linuron was mostly applied with an 18.1% proportion of application followed by isoproturon at 13.2% and the least in proportion of application was Neprapamide at 2.7%. Through enrichment cultures total of thirty one (31) isolates were obtained from diazinon and linuron contaminated soils of which thirteen (13) isolates had the ability to degrade linuron while eighteen (18) isolates could degrade diazinon. Degradation of the pesticides was monitored by High pressure liquid chromatography (HPLC). Bacterial isolates had significant levels (P