title: Modulation of tolerance to Cr(VI) and Cr(VI) reduction by sulfate ion in a Candida yeast strain isolated from tannery wastewater.
abstract: The main aim of this study was to investigate the influence of the sulfate ion on the tolerance to Cr(VI) and the Cr(VI) reduction in a yeast strain isolated from tannery wastewater and identified as Candida sp. FGSFEP by the D1/D2 domain sequence of the 26S rRNA gene. The Candida sp. FGSFEP strain was grown in culture media with sulfate concentrations ranging from 0 to 23.92 mM, in absence and presence of Cr(VI) [1.7 and 3.3 mM]. In absence of Cr(VI), the yeast specific growth rate was practically the same in every sulfate concentration tested, which suggests that sulfate had no stimulating or inhibiting effect on the yeast cell growth. In contrast, at the two initial Cr(VI) concentrations assayed, the specific growth rate of Candida sp. FGSFEP rose when sulfate concentration increased. Likewise, the greater efficiencies and volumetric rates of Cr(VI) reduction exhibited by Candida sp. FGSFEP were obtained at high sulfate concentrations. Yeast was capable of reducing 100% of 1.7 mM Cr(VI) and 84% of 3.3 mM Cr(VI), with rates of 0.98 and 0.44 mg Cr(VI)/L h, with 10 and 23.92 mM sulfate concentrations, respectively. These results indicate that sulfate plays an important role in the tolerance to Cr(VI) and Cr(VI) reduction in Candida sp. FGSFEP. These findings may have significant implications in the biological treatment of Cr(VI)-laden wastewaters.
authors: Departamento de Ingeniería Bioquímica, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Prolongación de Carpio y Plan de Ayala s/n, Colonia Santo Tomás, CP 11340, Mexico DF, Mexico.
authors: Flor
authors: F
authors: de María Guillén-Jiménez
authors: Liliana
authors: L
authors: Morales-Barrera
authors: Jesús
authors: J
authors: Morales-Jiménez
authors: César Hugo
authors: CH
authors: Hernández-Rodríguez
authors: Eliseo
authors: E
authors: Cristiani-Urbina
mesh_terms: D001673:Biodegradation, Environmental; D002175:Candida / Q000145:classification / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D002857:Chromium / Q000378:metabolism*; D004271:DNA, Fungal / Q000235:genetics; D007220:Industrial Waste / Q000032:analysis*; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D010802:Phylogeny; D012335:RNA, Ribosomal / Q000235:genetics; D012722:Sewage / Q000382:microbiology*; D013431:Sulfates / Q000378:metabolism*; D015003:Yeasts / Q000145:classification / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D004271:DNA, Fungal; D007220:Industrial Waste; D012335:RNA, Ribosomal; C065096:RNA, ribosomal, 26S; D012722:Sewage; D013431:Sulfates; D002857:Chromium