Comparison of dehalogenase activity between pure and mixed cultures of actinomycetes

FUENTES, MARÍA SOLEDAD; SÁEZ, JULIANA MARÍA; BOURGUIGNON, NATALIA; BENIMELI, CLAUDIA SUSANA; AMOROSO, MARIA JULIA

San Miguel de Tucumán

Encuentro; 45th Annual Meeting of the Argentine Society for Biochemestry and Molecular Biology; 2009

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB)

Halogenated compounds are important environmental pollutants. Lindane is a halogenated insecticide prohibited in most countries. Its bacterial degradation liberates chlorine by dehalogenase enzymes, playing an important role in this process. Lindane microbial degradation has been studied using pure and mixed microbial cultures. Mixed cultures are suitable for bioremediation because its biodiversity increase the catabolic pathways available for contaminant biodegradation. The aims of this work were to compare dehalogenase activities between pure and mixed cultures of actinomycetes isolated from pesticides contaminated soil, and its identification. Streptomyces sp. M7, S. coelicolor A3 and four actinomycetes isolates were cultivated alone in minimal medium (MM) with lindane for acclimation. These strains, as pure and mixed cultures, were cultivated in MM with lindane (1.66 mg L-1). Microbial cells were used to obtain cell-free extracts for dechlorinase activity assays. Enzyme activities ranged between 5.14 to 82.39 μmolCl-/h/mg protein. The mixed culture A5-M7 showed the best activity and it was higher than the sum of each activity of pure culture. The isolates were characterized by 16S rDNA amplifications and sequenced. Actinomycetes were mostly identified as members of Streptomyces genus. These native streptomycetes present better ability for lindane bioremediation in mixed cultures.