Spectrophotometric determination of pesticide biodegradation by Alcaligenes denitrificans and Alcaligenes xylosoxidans

ABSTRACTMSc THESİSSPECTROPHOTOMETRIC DETERMINATION of PESTICIDEBIODEGRADATION by Alcaligenes denitrificans and Alcaligenes xylosoxidansÖzlem ÖZTÜRKMENDEPARTMENT OF BIOLOGYINSTITUTE OF NATURAL APPLIED SCIENCESUNIVERSTY OF CUKUROVASupervisor : Assoc. Prof Dr. Sadık DİNÇERYear: 2005 Page: 72Jury : Assoc. Prof Dr. Sadık DİNÇERJury : Assoc. Prof Dr. Hatice GÜVENMEZJury : Assoc. Prof Dr. Mehmet Macit İLKİTIn this study, adsorption of 2,4-D a common used herbicide in our region onNa-Montmorillonite (MM), Ca-MM and MM and biodegradation by two Alcaligenesspecies isolated from soil were studied.2,4-D, was successfully absorbed on Na-MM, Ca-MM and MM. 2,4-Ddesorption from Na-MM in the first 72 hours was determined by liquid-liquidexraction. For Ca-MM 2,4-D desorbed after 72 hours and for MM 2,4-D protected itsamount in the minimal medium which was desorbed in the begining. Studies showedthat, depending on time, 2,4-D didn?t undergo abiotic degradation.Alcaligenes xylosoxidans and Alcaligenes denitrificans bacteria which wereisolated from soil identified by API 20NE and used for the studies. 2,4-Dbiodegradation studies with Alcaligenes xylosoxidans adsoption of 2,4-D on Na-MMreduced 70.8%, Ca-MM reduced 76.4% and MM reduced 61.6% of biodegradationwas determined and for Alcaligenes denitrificans adsorption of 2,4-D on Na-MMreduced 71.0%, Ca-MM reduced 77.2% and MM reduced 86.1% of biodegradationwas determined.Samples were extracted with ethyl acetate and read on UV spectrophotometer282 nm to determine the reduce of 2,4-D from minimal medium.The rate of 2,4-D biodegradation in mineral medium by Alcaligenesxylosoxidans was 28.4% and the rate of 2,4-D biodegradation in mineral medium byAlcaligenes denitrificans was 25.9% observed.Key Words: 2,4-D, Alcaligenes sp., Adsorption, Montmorillonite, BiodegradationII