ReviewBioremedial potential of microbial mechanisms of metal mobilization and immobilization
Introduction
The mechanisms by which microorganisms effect changes in metal speciation and mobility are fundamental components of biogeochemical cycles for metals, as well as all other elements including carbon, nitrogen, sulfur and phosphorus, with additional implications for plant productivity and human health [1••]. Almost all metal–microbe interactions have been examined in the context of environmental biotechnology as a means for removal, recovery or detoxification of inorganic and organic metal or radionuclide pollutants 2, 3, 4••, 5••. Although much research is laboratory based, there have been many developments to pilot/demonstration scale, with some processes apparently in successful commercial operation. It should also be noted that metal removal/transformation processes are intrinsic though less appreciated components of traditional means of water/sewage treatment as well as reed bed, lagoon and wetlands technologies 4••, 6. Molecular and genetic analysis is now furthering our understanding of microbial metal metabolism, including those aspects that have potential in biotechnology 7••, 8••. This review details recent advances in understanding of the most important mechanisms of microbial metal transformations within the contexts of bioremediation and environmental biogeochemistry.
Section snippets
Leaching
Leaching of mineral ores by acidophilic sulfur-oxidizing bacteria is an established bioindustry and although most interest arises from a hydrometallurgical perspective, leaching of contaminating metals from soils and other matrices is also possible [9••]. In fact, bioleaching using elemental sulfur as substrate can be better than sulfuric acid treatment for metal solubilization from contaminated aquatic sediments [10]. Iron- and sulfur-oxidizing bacteria, Thiobacillus ferrooxidans and
Biosorption
Biosorption encompasses those physico-chemical mechanisms by which metal species, radionuclides and so on, are removed from aqueous solution by microbial biomass or products. The approach can be multidisciplinary as the basic nature of experimentation is attractive to biologists, chemists and engineers, although inadequate dialogue between such groups has lead to considerable superficiality and duplication in the literature. It has also lead to the submersion of many other metal accumulation or
Conclusions
Mechanisms of microbial solubilization and immobilization of metal(loid)s, radionuclides and related substances are of clear potential for bioremediation, with some processes being integral to the operation of several successful in situ and ex situ processes. Although biosorption research is rather introverted with little recent development in an industrial context, work on metal leaching from contaminated matrices, metal(loid) transformation and bioprecipitation is leading to ‘field’
Update
Developments of relevance to this topic, published since submission of the manuscript, have occurred in several areas including biosorption, alkylation and reduction.
In an attempt to create a metal-capturing system for use in bioremediation, a peptide library was screened for binding to ZnO. By engineering a structural component of the fimbrae of E. coli to display a random peptide library, metal-chelating bacteria were isolated. Sequences responsible for Zn adherence were identified and
Acknowledgements
The author gratefully acknowledges financial support for his own work described from the Biotechnology and Biological Sciences Research Council (SPC 02812, SPC05211, BSW 05375) and the Royal Society.
References and recommended reading
Papers of particular interest, published within the annual period of review, have been highlighted as:
• of special interest
•• of outstanding interest
References (93)
Fungal production of citric and oxalic acid: importance in metal speciation, physiology and biogeochemical processes
Adv Microb Physiol
(1999)Biotransformation of uranium and other actinides in radioactive wastes
J Alloys Comp
(1998)- et al.
Bioremediation of metal contamination
Curr Opin Biotechnol
(1997) - et al.
Developments in terrestrial bacterial remediation of metals
Curr Opin Biotechnol
(1999) Treatment of metal-contaminated wastes: why select a biological process?
Trends Biotechnol
(1999)- et al.
Engineering of improved microbes and enzymes for bioremediation
Curr Opin Biotechnol
(1999) - et al.
Bioleaching of heavy metals from contaminated aquatic sediments using indigenous sulfur-oxidizing bacteria: a feasibility study
Water Sci Technol
(1998) - et al.
Effect of nitrogen source on the solubilization of different inorganic phosphates by an isolate of Penicillium rugulosum and two UV-induced mutants
FEMS Microbiol Ecol
(1999) - et al.
Characteristics of phosphate solubilization by an isolate of a tropical Penicillium rugulosum and two UV-induced mutants
FEMS Microbiol Ecol
(1999) - et al.
Computer-munching microbes: metal leaching from electronic scrap by bacteria and fungi
Process Metallurgy
(1999)
Lead mineral transformation by fungi
Curr Biol
Influence of microbes on the mobilization, toxicity and biomethylation of arsenic in soil
Sci Total Environ
The kinetics of metal uptake by microbial biomass: implications for the design of a biosorption reactor
Water Sci Technol
Biosorption of chromium VI by free and immobilized Rhizopus arrhizus
Environ Poll
Biosorption removal of cadmium from aqueous solution by using pretreated fungal biomass cultured from starch wastewater
Water Res
Bioaccumulation of some hazardous metals by sol-gel entrapped microorganisms
J Non-Crystalline Solids
Biosorption of cadmium ions by Actinomycetes and separation by flotation
Environ Poll
Poly(hydroxiethyl methacrylate) resins as supports for copper (II) biosorption with Arthrobacter sp.: matrix nanomorphology and sorption performances
Process Biochem
Biosorption of inorganic mercury and alkylmercury species onto Phanerochaete chrysosporium mycelium
Process Biochem
Removal of heavy metals using the fungus Apergillus niger
Bioresource Technol
Screening of marine microalgae for bioremediation of cadmium-polluted seawater
J Biotechnol
Biosorption of copper and zinc by Cymodocea nodosa
FEMS Microbiol Rev
Simultaneous biosorption of phenol and nickel (II) from binary mixtures onto dried aerobic activated sludge
Process Biochem
A comparison of the thermodynamics of metal adsorption onto two common bacteria
Chem Geol
Bioaccumulation of heavy metals with protein fusions of metallothionein to bacterial OMPs
Biochimie
Whole cell- and protein-based biosensors for the detection of bioavailable heavy metals in environmental samples
Analytica Chimica Acta
Sulfate-reducing bacterium grows with Cr(VI), U(VI), Mn(IV), and Fe(III) as electron acceptors
FEMS Microbiol Lett
Bacterial respiration of arsenic and selenium
FEMS Microbiol Rev
Transformation and tolerance of tellurite by filamentous fungi
Mycol Res
Copper accumulation by sulphate-reducing bacterial biofilms
FEMS Microbiol Lett
Production of two phosphatases by a Citrobacter sp. grown in batch and continuous culture
Enzyme Microbial Technol
Metal removal by sulphate-reducing bacteria from natural and constructed wetlands
J Appl Microbiol
Microbial heavy-metal resistance
Appl Microbiol Biotechnol
An integrated microbial process for the bioremediation of soil contaminated with toxic metals
Nat Biotechnol
Leaching heavy metals from contaminated soil by using Thiobacillus ferrooxidans or Thiobacillus thiooxidans
Geomicrobiol J
Decontamination of fly ash and used lime from municipal waste
Environ Management
Solubilization of phosphates and micronutrients by the plant-growth-promoting and biocontrol fungus Trichoderma harzianum Rifai 1295-22
Appl Environ Microbiol
Heavy metals bioremediation of soil
Mol Biotechnol
Fungi as potential bioremediation agents in soil contaminated with heavy or radioactive metals
Biochem Soc Trans
Wolfiporia cocos — a potential agent for composting or bioprocessing Douglas-fir wood treated with copper-based preservatives
Material Organismen
Adsorption and degradation of dimethyl selenide in soil
Environ Sci Technol
Accelerated volatilization rates of selenium from different soils
Biol Trace Element Res
Effects of soil moisture, depth, and organic amendments on selenium volatilization
J Environ Qual
Effect of soil moisture on dimethylselenide transport and transformation to non-volatile selenium
Environ Sci Technol
Oxidation of arsenite to arsenate by a bacterium isolated from an aquatic environment
BioMetals
Bacterial and chemical reductive dissolution of Mn-, Co-, Cr-, and Al-substituted geothites
Geomicrobiol J
Cited by (477)
Release of chromium from Cr(III)- and Ni(II)-substituted goethite in presence of organic acids: Role of pH in the formation of colloids and complexes
2023, Science of the Total EnvironmentImpacts of sulfonic acids on fungal manganese oxide production
2023, Geochimica et Cosmochimica ActaBioremediation potential of rhizosphere microbes—current perspectives
2023, Rhizobiome: Ecology, Management and Application