CU(II) REMOVAL BY Rhodotorula mucilaginosa RCL-11 IN SEQUENTIAL BATCH CULTURES

VILLEGAS L.B.; AMOROSO M.J.; CASTELLANOS DE FIGUEROA, LUCÍA INÉS; SIÑERIZ FAUSTINO

WATER SCIENCE AND TECHNOLOGY

IWA Publishing

Lugar: London, UK; Año: 2008 p. 1 - 1

0273-1223

ABSTRACT. The present study explored the ability of the yeast Rhodotorula mucilaginosa RCL-11 to adapt to increasing Cu(II) concentrations, measuring oxidative stress through superoxide dismutase and catalase activity in two parallel sequential batch assays. One assay was performed in Erlenmeyer flasks without controlled aeration and a second in a fermentor in which the dissolved oxygen was maintained at 30% saturation. Both assays were carried out by increasing Cu(II) concentrations in five sequential steps: 0; 0.1; 0.2; 0.5 and 1 mM. Each assay was incubated at 30ºC, 250 rpm and pH 5.5. While growth parameters of R. mucilaginosa RCL-11 decreased with increasing Cu(II) concentration in the culture medium, the oxidative stress level increased in both assays. Cells grown under controlled oxygen conditions (fermentor) showed a higher specific copper bioaccumulation and glucose consumption and a decrease in growth rate when compared with cells grown without controlled aeration (flasks). SOD activity was higher under controlled than under uncontrolled conditions, whereas CAT activity was similar under both test conditions. Cu(II) bioaccumulation by R. mucilaginosa RCL-11 and a possible increase in this capacity by adaptation of the strain under controlled aeration, would allow the use of this strain in treatment of effluents with high copper contents.