Open AccessCu(II) removal by Rhodotorula mucilaginosa RCL-11 in sequential batch cultures
Author(s) -
Liliana Beatriz Villegas,
Maria Julia del R. Amoroso,
Lucía I. C. de Figueroa,
Faustino Siñeríz
Publication year - 2009
Publication title -
water science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.406
H-Index - 137
eISSN - 1996-9732
pISSN - 0273-1223
DOI - 10.2166/wst.2009.457
Subject(s) - aeration , bioremediation , bioaccumulation , superoxide dismutase , catalase , erlenmeyer flask , chemistry , food science , effluent , bioreactor , laboratory flask , yeast , oxidative stress , biochemistry , microbiology and biotechnology , biology , environmental chemistry , chromatography , environmental engineering , bacteria , organic chemistry , genetics , engineering
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 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 30°C, 250 rpm and pH 5.5. While growth parameters of R. mucilaginosa RCL-11 decreased 90–95% with increasing Cu(II) concentration in the culture medium, the oxidative stress level increased from 30 to 55% in both assays. Cells grown under controlled oxygen conditions showed 30% more copper bioaccumulation and 10% glucose consumption when compared with cells grown without aeration. SOD activity was higher under controlled than whitout areation, 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 represent a potential valuable tool for treatment of effluents or water bioremediation with high copper contents.