مطالعه تجزیه علف کش آترازین به وسیله باکتری های سودوموناس فلورسنس و سودوموناس آرژینوزا به عنوان منبع نیتروژن و کربن در شرایط آزمایشگاهی

Abstract Atrazine biodegradation by bacteria is one of the most important aspects of bioremediation. Atrazine can be degraded by various species of bacteria. Bacteria use atrazine as nitrogen and carbon sources. The aim of this study was to determine atrazine degradation by Pseudomonas fluorescence and Pseudomonas aeruginosa. The experiment consisted of two Pseudomonas bacteria, three levels of atrazine concentrations (100, 200 and 300 mg.l-1) and four types of MSM medium (complete, without nitrogen, without carbon and without nitrogen and carbon source). The results showed that both bacteria were able to degrad atrazine at all concentrations. However, increasing atrazine concentration led to more degradation of this herbicide. Biodegradation of atrazine by Pseudomonas fluorescence in concentrations of 100, 200 and 300 mg.l-1 was 18.5, 48.91 and 72.6% respectively and it was 19.08, 33.83 and 62.66% respectively for Pseudomonas aeruginosa in a period of 48 hr. The most degradation of herbicide was observed by Pseudomonas fluorescence in MSM medium without N treatment. In this study nitrogen source was a limiting factor in degradation of atrazine by Pseudomonas fluorescent. Nitrogen source had no significant effect on degradation of atrazine by Pseudomonas aeruginosa in comparison with other MSM medium. In addition, the carbon source in both conditions (with and without) had no significant effect on atrazine degradation by both bacteria. Keywords: Atrazine, Biodegradation, Pseudomonas aeruginosa, Pseudomonas fluorescence