BIOREMEDIATION OF METHOXYCHLOR BY NATIVE ACTINOMYCETES. EFFECT OF TEMPERATURE, pH AND PESTICIDE CONCENTRATION

CUOZZO, S.A.; BOURGUIGNON, N.; FUENTES, M.S.; SÁEZ, J.M.; BENIMELI, C.S, ; AMOROSO, M.J.

Puerto Madryn

Congreso; XLVI Reunión anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2010

Argentina de Investigación en Bioquímica y Biología Molecular

Methoxychlor (MTX) is an organochlorine pesticide that was used in industrial and agricultural activities. MTX is a persistent, bioaccumulative, toxic chemical for which it was prohibited in many countries; nevertheless it is even found as environmental pollutant. The aims of this work were select an actinomycete strain available to biodegrade MTX and optimize the environmental conditions for this process. Streptomyces sp. M7, S. coelicolor A3 and four actinomycetes isolates from a contaminated soil were cultivated in minimal medium with MTX (1.66 mg/L) as sole carbon source. Microbial growth, MTX remained and chlorine ions released were determined. The actinomycete selected was cultivated at different temperature, pH and MTX concentration conditions. The isolates were characterized by 16S rDNA amplifications and sequenced and they were identified as members of Streptomyces genus. Streptomyces sp. A14 showed the best growing (0.39 mg/mL), MTX removal (100%) and chlorine released (DA540=0.14). Temperature of 30 ºC and pH 7 were the best conditions for MTX biodegradation by Streptomyces sp. A14. Finally, these strain removed 97.6% of MTX at the higher pesticide concentration (16.60 mg/L). Our results suggest that Streptomyces sp. A14 has a big potential for bioremediation of MTX contaminated soils and these is the first evidence of aerobic MTX degradation.