Cr(VI) reduction by cell-free extracts of Pichia jadinii and Pichia anomala isolated from textile-dye factory effluents

MARTORELL MARÍA MARTHA; FERNÁNDEZ P,; FARIÑA J.I.; CASTELLANOS DE FIGUEROA, LUCÍA INÉS

INTERNATIONAL BIODETERIORATION & BIODEGRADATION

ELSEVIER SCI LTD

Lugar: Amsterdam; Año: 2012 vol. 71 p. 80 - 85

0964-8305

Chromium-resistant yeasts isolated from soils can be used to reduce toxic Cr(VI) from contaminated environments. This study assessed in vitro reduction of hexavalent Cr using cell-free extract (CFE) of Pichia jadinii M9 and Pichia anomala M10, two yeasts isolated from a tannery effluent. CFE were obtained using sonication end glass beads and then characterized based on optimal temperature, pH, use of electron donors, metal ions and initial Cr(VI) concentration in the reaction mixture. Both CFEs reduced Cr(VI) using NAD(P)H as an electron donor and were highly inhibited by Hg2+ and Mn2+. The CFE from P. jadinii M9 showed the highest chromate reductase activity at 60ºC and pH 6.0 in the presence of Cu2+ or Na+, while P. anomala M10 CFE had the maximum activity at 50ºC and pH 7.0 in Cu2+. Initial Cr(VI) concentrations of 1.3 and 1.7 for CFE of Pichia jadinii M9 and Pichia anomala M10 respectively may be toxic. These results are an important contribution to the knowledge of Cr(VI) reducing enzymatic mechanisms in yeasts.