Compost as a source of microbial isolates for the bioremediation of heavy metals: in vitro selection.
Heavy metal pollution has become a major environmental concern nowadays and the bioremediation of polluted habitats is an increasingly popular strategy due to both its efficiency and safety. A screening and selection protocol based on different composting processes was designed in order to isolate heavy metal-resistant microorganisms. A collection of 51 microorganisms was obtained and most of them showed the capability to tolerate heavy metals in multi-polluted aqueous systems (Cd(II), Cr(VI), Ni, Pb, Zn(II)), as well as to remove them. The highest detoxification ratios were observed for Pb. Some of the isolates detoxifying more than a 90% of this metal, while the other metals were removed in a range between 20% and 60%. The best isolates (Graphium putredinis, Fusarium solani, Fusarium sp. and Penicillium chrysogenum) were further assayed in order to determine the predominant removal mechanism and the potential use of their dead biomass as a biosorbent. Intracellular accumulation was the prevalent mechanism for most isolates and metals, with the exception of Ni. In this case, the proportion removed by extracellular adsorption was similar or even higher than that removed by intracellular accumulation. Thus, the efficiency of living cells was higher than that of dead biomass except in the case of Ni.
Department of Applied Biology, Engineering Higher School, University of Almería-International Excellence Campus in Agri-Food, CeiA3, 04120 Almería, Spain. mcvargas@ual.es
María del Carmen
Mdel C
Vargas-García
María José
MJ
López
Francisca
F
Suárez-Estrella
Joaquín
J
Moreno
D000327:Adsorption; D001673:Biodegradation, Environmental; D018533:Biomass; D004352:Drug Resistance, Microbial; D005670:Fusarium / Q000235:genetics / Q000378:metabolism*; D019216:Metals, Heavy / Q000302:isolation & purification / Q000378:metabolism* / Q000494:pharmacology; D010408:Penicillium chrysogenum / Q000235:genetics / Q000378:metabolism*; D012987:Soil; D012988:Soil Microbiology
D019216:Metals, Heavy; D012987:Soil