Hexavalent chromium removal in vitro and from industrial wastes, using chromate-resistant strains of filamentous fungi indigenous to contaminated wastes

• Published in: Canadian journal of microbiology Vol. 52; no. 9; pp. 809 - 815
• Main Authors: Acevedo-Aguilar, F.J, Espino-Saldaña, A.E, Leon-Rodriguez, I.L, Rivera-Cano, M.E, Avila-Rodriguez, M, Wrobel, K, Lappe, P, Ulloa, M, Gutiérrez-Corona, J.F
• Format: Journal Article
• Language: English
• Published: Ottawa, Canada NRC Research Press 01.09.2006; National Research Council of Canada; Canadian Science Publishing NRC Research Press
• Subjects: Analysis; Aspergillus; Aspergillus - drug effects; Aspergillus - metabolism; Bacteria; Biological and medical sciences; biological treatment; Biology of microorganisms of confirmed or potential industrial interest; Biomass; Biotechnology; Cells; chemical speciation; Chromates - metabolism; Chromates - toxicity; Chromium; Chromium - metabolism; Chromium compounds; Fundamental and applied biological sciences. Psychology; Fungi; Fungi - drug effects; Fungi - metabolism; hexavelent chromium; Industrial Waste - analysis; Industrial Waste - prevention & control; Industrial wastes; metal tolerance; Microbiology; Mission oriented research; Oxidation-Reduction; Penicillium; Physiological aspects; Physiology and metabolism; reduction; Soil Microbiology; Soil Pollutants - metabolism; Time Factors; waste treatment; Chemical pollution; Fungi; Resistance; Aspergillus; Industrial waste; Penicillium; Fungi Imperfecti; Bioremediation; Chromium VI; Contamination; Thallophyta; Strain
• ISSN: 0008-4166; 1480-3275
• DOI: 10.1139/w06-037

Two chromate-resistant filamentous fungi, strains H13 and Ed8, were selected from seven independent fungal isolates indigenous to Cr(VI)-contaminated soil because of their ability to decrease hexavalent chromium levels in the growth medium. Morphophysiological studies identified strain H13 as a Penicillium sp. isolate and Ed8 as an Aspergillus sp. isolate. When incubated in minimal medium with glucose as a carbon source and in the presence of 50 µg/mL Cr(VI), these strains caused complete disappearance of Cr(VI) in the growth medium after about 72 h of incubation. Total chromium concentration in growth medium was constant during culture growth, and no accumulation of chromium in fungal biomass was observed. Quantitative determinations of oxidized and reduced chromium species during the reduction process revealed stoichiometric conversion of Cr(VI) to Cr(III). A decrease in Cr(VI) levels from industrial wastes was also induced by Ed8 or H13 biomass. These results indicate that chromate-resistant filamentous fungi with Cr(VI)-reducing capability could be useful for the removal of Cr(VI) contamination.Key words: Cr(VI) reduction, Cr(VI) resistance, filamentous fungi, Aspergillus sp., Penicillium sp., industrial wastes.