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

ROBERTO O. GARCIA; POLTI M.A.; AMOROSO M.J.; ABATE C.M.

Tucumán

Jornada; XXII Jornadas Científicas de Biología de Tucumán; 2006

Sociedad de Biología de Tucumán

Chromium is usually found in nature in its trivalent (III) and hexavalent (VI) state. Cr (VI) is 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 process. Streptomyces MC1 strain was previously selected by its resistance to Cr(VI). To optimize the culture conditions, SE medium was inoculated with Streptomyces MC1, and it was tested different temperatures (25, 30 and 35 ºC) and pHs (5, 7 and 9). For study Cr (VI) resistance, Streptomyces MC1 have been grown in SE medium containing Cr (VI) 10 mg l-1under optimum conditions of growth fro  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.