Chromate Reductase Activity Of Streptomyces MC1

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

Pinamar

Congreso; X Congreso PABMB, XLI Reunión Anual SAIB y XX Reunión Anual SAN; 2005

SAIB

In natural water and subsurface soils chromium occurs in two major oxidation states: III and VI. Cr (VI) is approximately 1,000-fold more cytotoxic and mutagenic than Cr (III). As the application of Cr is extensive in several industries, chromium-associated pollution is an increasing problem. Biological transformation of Cr (VI) to Cr (III) by enzymatic reduction is a means of chromium decontamination. Actinomycetes are the dominant population in soil. Their metabolic diversity and the particular growth characteristics indicates them as agents for bioremediation. The aim was study the chromate reductase activity of Streptomyces MC1, a chromium resistant strain. Streptomyces MC1 was grew in minimal medium with Cr (VI) 1 mM, and without this metal, using glucose or glycerol as carbon source. After seven days, cells were harvested, crushed and resuspended. After centrifugation, enzyme activity was determinate using sodium phosphate buffer, NADH and Cr (VI) as substrate. The activity was 49 and 22 nmol/min/mg protein when the strain was grew with glucose or glycerol without the metal, however, this activity was reduced at 12 or 11 nmol/min/mg protein after seven days of growth. Maybe Cr (III) makes a retro-inhibition effect. Streptomyces MC1 could be used for Cr (VI) reduction in biotechnological processes.