title: Recovery of palladium(II) by methanogenic granular sludge.
abstract: This is the first report that demonstrates the ability of anaerobic methanogenic granular sludge to reduce Pd(II) to Pd(0). Different electron donors were evaluated for their effectiveness in promoting Pd reduction. Formate and H2 fostered both chemically and biologically mediated Pd reduction. Ethanol only promoted the reduction of Pd(II) under biotic conditions and the reduction was likely mediated by H2 released from ethanol fermentation. No reduction was observed in biotic or abiotic assays with all other substrates tested (acetate, lactate and pyruvate) although a large fraction of the total Pd was removed from the liquid medium likely due to biosorption. Pd(II) displayed severe inhibition towards acetoclastic and hydrogenotrophic methanogens, as indicated by 50% inhibiting concentrations as low as 0.96 and 2.7 mg/L, respectively. The results obtained indicate the potential of utilizing anaerobic granular sludge bioreactor technology as a practical and promising option for Pd(II) reduction and recovery offering advantages over pure cultures.
authors.affiliation: Department of Chemical and Environmental Engineering, University of Arizona, P.O. Box 210011, Tucson, AZ, 85721, USA; División de Ciencias Ambientales, Instituto Potosino de Investigación Científica y Tecnológica, Camino a la Presa San José 2055, Col. Lomas 4ª. Sección, C. P. 78216, San Luis Potosí, SLP, Mexico. Electronic address: aurora.pat@ipicyt.edu.mx.
authors.forename: Aurora M
authors.initials: AM
authors.lastname: Pat-Espadas
authors.affiliation: Department of Chemical and Environmental Engineering, University of Arizona, P.O. Box 210011, Tucson, AZ, 85721, USA.
authors.forename: James A
authors.initials: JA
authors.lastname: Field
authors.affiliation: Department of Chemical and Environmental Engineering, University of Arizona, P.O. Box 210011, Tucson, AZ, 85721, USA.
authors.forename: Lila
authors.initials: L
authors.lastname: Otero-Gonzalez
authors.affiliation: División de Ciencias Ambientales, Instituto Potosino de Investigación Científica y Tecnológica, Camino a la Presa San José 2055, Col. Lomas 4ª. Sección, C. P. 78216, San Luis Potosí, SLP, Mexico.
authors.forename: Elías
authors.initials: E
authors.lastname: Razo-Flores
authors.affiliation: División de Ciencias Ambientales, Instituto Potosino de Investigación Científica y Tecnológica, Camino a la Presa San José 2055, Col. Lomas 4ª. Sección, C. P. 78216, San Luis Potosí, SLP, Mexico.
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Cervantes
authors.affiliation: Department of Chemical and Environmental Engineering, University of Arizona, P.O. Box 210011, Tucson, AZ, 85721, USA.
authors.forename: Reyes
authors.initials: R
authors.lastname: Sierra-Alvarez
mesh_terms: D000693:Anaerobiosis / Q000187:drug effects; D019149:Bioreactors / Q000382:microbiology; D000431:Ethanol / Q000494:pharmacology; D005561:Formates / Q000494:pharmacology; D006859:Hydrogen / Q000494:pharmacology; D008697:Methane / Q000096:biosynthesis*; D010084:Oxidation-Reduction / Q000187:drug effects; D010165:Palladium / Q000302:isolation & purification* / Q000378:metabolism*; D059027:Recycling; D012722:Sewage / Q000382:microbiology*
chemical_list: D005561:Formates; D012722:Sewage; C030544:formic acid; D000431:Ethanol; D010165:Palladium; D006859:Hydrogen; D008697:Methane
keywords: Anaerobic granular sludge; Biosorption; Chemical reduction; Methanogenic inhibition; Palladium bioreduction