title: Cu(II) removal by Rhodotorula mucilaginosa RCL-11 in sequential batch cultures.
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 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 degrees 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 without aeration, 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.
authors.affiliation: PROIMI-CONICET, Av. Belgrano y Pje. Caseros. T4001MVB Tucumán, Argentina. lbvilleg@gmail.com
authors.forename: Liliana B
authors.initials: LB
authors.lastname: Villegas
authors.forename: María J
authors.initials: MJ
authors.lastname: Amoroso
authors.forename: Lucía I C
authors.initials: LI
authors.lastname: de Figueroa
authors.forename: Faustino
authors.initials: F
authors.lastname: Siñeriz
authors.forename: Faustino
authors.initials: F
authors.lastname: Siñeriz
mesh_terms: D001673:Biodegradation, Environmental; D019149:Bioreactors; D002374:Catalase / Q000378:metabolism; D003300:Copper / Q000302:isolation & purification* / Q000378:metabolism* / Q000633:toxicity; D004785:Environmental Pollutants / Q000302:isolation & purification* / Q000378:metabolism* / Q000633:toxicity; D005285:Fermentation; D018384:Oxidative Stress / Q000187:drug effects; D012248:Rhodotorula / Q000187:drug effects / Q000201:enzymology / Q000254:growth & development* / Q000378:metabolism*; D013482:Superoxide Dismutase / Q000378:metabolism
chemical_list: D004785:Environmental Pollutants; D003300:Copper; D002374:Catalase; D013482:Superoxide Dismutase