Viability and release of complexing compounds during accumulation of heavy metals by a brewer's yeast.
Saccharomyces cerevisiae NCYC 1190 cells accumulated (after 1 h) lead and cadmium at similar levels, and to a lesser degree also copper. During heavy metal accumulation, there was a considerable loss of viability of copper-treated cells (about 99% in the first 20 min of contact with the metal), and a less pronounced lethal effect on cadmium- and lead-treated cells (about 66% and 46% after 1 h of contact with cadmium or lead, respectively) was detected. During copper accumulation, a leakage of UV-absorbing compounds and inorganic phosphate was observed; this did not occur with lead, whereas with cadmium a small amount of leakage of inorganic phosphate was detected. The filtrates of copper-treated cells contained copper-binding molecules. The copper-binding capacity of the filtrates increased with time according to the release of inorganic phosphate and UV-absorbing compounds. These compounds can bind an appreciable quantity of metal ions, making them unavailable for cell uptake and thus reducing the efficiency of heavy metals removal by yeast cells.
Soares
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CIEA-Departamento de Engenharia Química, Instituto Superior de Engenharia do Instituto Politécnico do Porto, Rua Dr António Bernardino de Almeida, 431, 4200-072 Porto, Portugal. evsoares@deq.isep.ipp.pt
Duarte
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Boaventura
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Soares
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D018533:Biomass; D007700:Kinetics; D019216:Metals, Heavy / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D013056:Spectrophotometry, Ultraviolet
D019216:Metals, Heavy