Cr (VI) disminution by Streptomyces MC1 in soil extract medium.

GARCÍA, ROBERTO; POLTI, MARTA ALEJANDRA; AMOROSO, MARÍA JULIA; ABATE; CARLOS MAURICIO

Tucumán

Jornada; XXII Jornadas de la Sociedad de Biología de Tucumán; 2005

Sociedad de Biología de Tucumán

  Chromium is usually found in nature in its trivalent (III) and hexavalent (VI) state. Cr (VI) are 1,000-fold more toxic and mutagenic than Cr (III) compounds because are highly soluble in water, diffusion through biological membranes and subsequent interaction with intracellular proteins and nucleic acids. One alternative to this problem is metal reduction from Cr (VI) to Cr (III) by microorganisms. Actinomycetes are a group of bacteria, with high potential in bioremediation processes. Streptomyces MC1 strain was previously selected by its resistance to Cr (VI). To optimise the culture conditions, SE medium was inoculated with Streptomyces MC1, and it was tested different temperatures (25, 30 and 35 °C) and pHs (5, 7 and 9). For study Cr (VI) resistance, Streptomyces MC1 have been grow in SE medium containing Cr (VI) 10 mg l–1 under optimum conditions of growth for 4 days. Cr (VI) concentration was analyzed using diphenilcarbazide. The optimal conditions were at 30 ºC and pH 7.In SE medium in presence of Cr (VI), the major disappearance of metal was carried out into the firsts 24 hours of growth (40%) and then it kept a constant value. These results confirm that Streptomyces MC1 has a very high potential to be used in bioremediation soil process.