TY - JOUR
T1 - Metal uptake by microalgae
T2 - underlying mechanisms and practical applications
AU - Monteiro, Cristina M.
AU - Castro, Paula M. L.
AU - Malcata, F. Xavier
PY - 2012/3
Y1 - 2012/3
N2 - Metal contamination of a few aquatic, atmospheric, and soil ecosystems has increased ever since the industrial revolution, owing to discharge of such elements via the effluents of some industrial facilities. Their presence to excessive levels in the environment will eventually lead to serious health problems in higher animals owing to accumulation throughout the food web. Current physicochemical methods available for recovery of metal pollutants (e.g., chemical precipitation, oxidation/reduction, or physical ion exchange) are either expensive or inefficient when they are present at very low concentrations. Consequently, removal of toxic metals by microorganisms has emerged as a potentially more economical alternative. Microalgae (in terms of both living and nonliving biomass) are an example of microorganisms suitable to recover metals and able to attain noteworthy percent removals. Their relatively high metal-binding capacities arise from the intrinsic composition of their cell walls, which contain negatively charged functional groups. Consequently, microalgal cells are particularly efficient in uptake of those contaminants when at low levels. Self-defense mechanisms developed by microalgal cells to survive in metal-containing media and environmental factors that affect their removal (e.g., pH, temperature, and biomass concentration) are reviewed here in a comprehensive way and further discussed in attempts to rationalize this form of remediation vis-a-vis with conventional nonbiological alternatives.
AB - Metal contamination of a few aquatic, atmospheric, and soil ecosystems has increased ever since the industrial revolution, owing to discharge of such elements via the effluents of some industrial facilities. Their presence to excessive levels in the environment will eventually lead to serious health problems in higher animals owing to accumulation throughout the food web. Current physicochemical methods available for recovery of metal pollutants (e.g., chemical precipitation, oxidation/reduction, or physical ion exchange) are either expensive or inefficient when they are present at very low concentrations. Consequently, removal of toxic metals by microorganisms has emerged as a potentially more economical alternative. Microalgae (in terms of both living and nonliving biomass) are an example of microorganisms suitable to recover metals and able to attain noteworthy percent removals. Their relatively high metal-binding capacities arise from the intrinsic composition of their cell walls, which contain negatively charged functional groups. Consequently, microalgal cells are particularly efficient in uptake of those contaminants when at low levels. Self-defense mechanisms developed by microalgal cells to survive in metal-containing media and environmental factors that affect their removal (e.g., pH, temperature, and biomass concentration) are reviewed here in a comprehensive way and further discussed in attempts to rationalize this form of remediation vis-a-vis with conventional nonbiological alternatives.
KW - Biosorption mechanisms
KW - Metals
KW - Microalgae
KW - Multimetal systems
KW - Toxicity
UR - http://www.scopus.com/inward/record.url?scp=84859649733&partnerID=8YFLogxK
U2 - 10.1002/btpr.1504
DO - 10.1002/btpr.1504
M3 - Review article
C2 - 22228490
AN - SCOPUS:84859649733
SN - 8756-7938
VL - 28
SP - 299
EP - 311
JO - Biotechnology Progress
JF - Biotechnology Progress
IS - 2
ER -