International Journal of Microbiological Research 4 (3): 241-252, 2013 ISSN 2079-2093 © IDOSI Publications, 2013 DOI: 10.5829/idosi.ijmr.2013.4.3.7687 Corresponding Author: Fawzy Eissa, Department of Environment and Bio-Agriculture, Faculty of Agriculture, Al-Azhar University, 11884, Nasr City, Cairo, Egypt. 241 Bioremediation of Atrazine-Contaminated Water and Soils by Pseudomonas fluorescens E.B. Belal, F.I. Eissa, N.A. Zidan and I.N. Nasr 1 2 3 4 Agricultural Botany Department (Agricultural Microbiology), Faculty of Agriculture, 1 Kafrelsheikh University, 33516, Kafr El-Sheikh, Egypt Department of Environment and Bio-Agriculture, 2 Faculty of Agriculture, Al Azhar University, 11884, Cairo, Egypt Department of Pesticides, Faculty of Agriculture, 3 Kafrelsheikh University, 33516, Kafr El-Sheikh, Egypt Central Agricultural Pesticides Laboratory, Agricultural Research center, Giza, Egypt 4 Abstract: Biodegradation of atrazine was investigated in water and soil. Atrazine degrading bacterium (designated strain E10) was isolated from maize soil previously treated with atrazine using enrichment technique. Based on morphological, physiological and 16S rDNA, this bacterium was identified as Pseudomonas fluorescens. It was capable of using atrazine as a sole source of carbon and nitrogen. P. fluorescens biomass and atrazine degradation were found to be optimum at pH 7 and 30°C. Additional carbon sources (i.e., glucose, sucrose and phenol) and nitrogen sources (i.e., ammonium sulfate, sodium nitrate and urea) decreased atrazine degradation. P. fluorescens was able to degrade atrazine completely in liquid medium at pH 7 and 30°C after 30 days and its half-life was 9 days compared to 64.2 days in uninoculated medium. There was no toxicity of detected atrazine in the supernatant after 30 days of incubation with P. fluorescens on Azotobacter chroococcum as microbial bioassay test. Four metabolites viz. hydroxyatrazine, deethylatrazine, deisopropylatrazine and deethyldeisopropylatrazine were identified by gas chromatography coupled with mass spectrometry analysis in the liquid cultures. Results showed also that atrazine was degraded faster by P. fluorescens in sandy soil than clay soil compared to their respective uninoculated soils after 30 days and their half-lives were 8.7, 14.4, 119.5 and 150.6 days, respectively. The dissipation of atrazine was coinciding with increasing P. fluorescens biomass in both atrazine contaminated soils. This study has shown that P. fluorescens could be applied to remediate atrazine contaminated soils and water. Key words: Atrazine Biodegradation Degradation Products INTRODUCTION world for controlling broadleaf and grassy weeds and is The expanding use of pesticides is a problem various living organisms [3]. Because of its high especially in the developing nations, where agricultural mobility and persistence in soil and its massive systems demonstrate an increasing reliance on pesticides, application, atrazine has often been detected in surface with limited regulation and no measure of environmental and groundwater at concentrations well above the contamination, which lead to potentially serious health permitted limits [4-6]. problems [1]. Once pesticides are applied to the field, they Atrazine is considered as a potential environmental can be carried with runoff to surface water, percolate to contaminant and considered also as one of the worst groundwater, or be retained in the soil column [2]. ground water pollutants [7, 8]. Atrazine can also affect Atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino) human and other animals directly because it can be up -s-triazine] is the most commonly used herbicide in the taken by plants and transferred to the food chain [9]. quite persistent in neutral environment and toxic to