| Summary: | Hexaclorociclohexano (HCH), pesticida organoclorado mundialmente utilizado, apresenta efeitos tóxicos à saúde humana e ao meio ambiente. Os microrganismos degradadores mais conhecidos são as Sphingomonas sp. Técnicas de biodegradação foram aplicadas em duas etapas. A primeira focou na biorremediação de solo contaminado, de Santo André SP, e foi realizada em biorreatores no Instituto de Pesquisas Tecnológicas (IPT). Experimentos nas fases sólida e semi-sólida apresentaram até 90% de degradação de HCH no solo. A segunda parte, na Universidade de Groningen (RuG), Países Baixos, focou no tratamento de soluções contaminadas usando enzimas selvagens e variantes desenhadas computacionalmente. Mutantes foram construídas, expressadas e purificadas. Ensaios de Thermofluor® mostraram que as variantes estavam enoveladas. Ensaios enzimáticos foram realizados em solução aquosa com b-HCH e dimetil sulfóxido (5%), sendo as amostras extraídas com acetato de etila e analisadas por cromatografia gasosa com detector de captura de elétrons. As variantes apresentaram atividade.
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Hexachlorocyclohexane (HCH) is an organochlorine pesticide used world-wide which shows toxic effects in human health and causes environmental problems. The most known HCH-degrading microorganisms are Sphingomonas sp. Biodegradation techniques were applied in this work, divided in two parts. The first one focused on the bioremediation of a contaminated soil, from Santo Andre - SP, in bioreactors at the Institute for Technological Research (IPT). Experiments were carried in solid and slurry phases, which could achieve around 90% of HCH degradation. The second part was developed at the University of Groningen (Rug), The Netherlands. Contaminated solutions were treated with wild-type enzymes and computationally designed variants. Mutants were constructed, expressed and purified. Thermofluor® assay showed that all variants were well folded. Enzymatic assays were carried in aqueous solution with b-HCH and dimethyl sulfoxide (5%). The samples were extracted with ethyl acetate and analysed by gas chromatography using an electron capture detector. The variants were actives.
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