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Final Report: Removal of Heavy Metals from Hazardous Wastes by Protein Complexation for their Ultimate Recovery and Reuse
EPA Grant Number: R825549C018Subproject: this is subproject number 018 , established and managed by the Center Director under grant R825549
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
Center: HSRC (1989) - Great Plains/Rocky Mountain HSRC
Center Director: Erickson, Larry E.
Title: Removal of Heavy Metals from Hazardous Wastes by Protein Complexation for their Ultimate Recovery and Reuse
Investigators: Ghosh, Sam
Institution: University of Utah
EPA Project Officer: Manty, Dale
Project Period: February 1, 1989 through February 1, 1992
Project Amount: Refer to main center abstract for funding details.
RFA: Hazardous Substance Research Centers - HSRC (1989)
Research Category: Heavy Metal Contamination of Soil/Water
Description:
Objective:The ultimate goal of this research was to develop a closed-loop bioprocess system in which special biological cultures are utilized to remove heavy metals from contaminated waters by biopolymeric complexation following which the complexed metals are extracted in concentrated solution for their reuse; the liberated biopolymers are then recycled for removal of more heavy metals from the system influent. Specific project objectives were: (1) to study the effect of organism growth rate on metal uptake; (2) to delineate the predominant metal-uptake mechanisms for aerobic and anaerobic cultures; (3) to study metal uptake kinetics and efficiency; (4) to investigate the effect of heavy metals on cell viability; (5) to study the metal-uptake capabilities of viable and non-viable cultures; (6) to compile information on metal-uptake hierarchies in environments containing mixtures of heavy metals; (7) to study metal uptakes by unacclimated and acclimated cultures; and (8) to investigate the feasibility of enhancing metal uptake by stimulating the synthesis of metallothionein-like proteins in the presence of its precursors and special nutrients.
It is known that heavy metals are removed owing to their binding with the carboxyL phosphate, sulfhydryl, and organosulfate groups of proteins, lipids, nucleic acids, phospholipids, lipoproteins, polysaccharides, and other biopolymers. We hypothesized that these biopolymers are synthesized in larger quantities when organisms are in the declining or the stationary growth phase. Consequently, organisms maintained at a lower growth rate were expected to remove more heavy metals than those in the exponential growth phase. Aerobic cultures were cultivated in chemostats operated at two selected dilution rates corresponding to high and low growth rates, and the metal uptake capabilities of these cultures grown on a glucose-mineral-salts minimal medium were studied.
The microbiology literature suggests that sulfur-rich proteins, known as metallothioneins, are often responsible for rapid uptake of heavy metals. Two sulfurbearing amino acids, cysteine and cystine, were therefore included in the growth medium of a chemostat to stimulate the production of metallothionein-like proteins. Metal-uptake studies were conducted with this chemostat culture. Since biopolymer production creates a higher demand for ATP relative to the available total cellular ATP, it was reasoned that inclusion of B-glycerophosphate (BGP), a soluble organic phosphate, as an ATP precursor, and other nutrients in the growth medium should further stimulate metallothionein synthesis and the uptake of heavy metals. Because synthesis of metal-complexing biopolymers requires the presence of a metal inducer, experiments were planned to study the effect of the presence of a metal inducer in the minimal growth medium (i.e., the effect of acclimation) on the metal-uptake capacity of the chemostat culture. Similarly, chemostat cultures were developed in the presence of an inducer plus cystine, BGP, and a common nutrient, peptone, in an attempt to stimulate metallothionein synthesis to enhance heavy metal uptake. Two types of batch runs were conducted with the various chemostat cultures: kinetic runs with a heavy metal concentration of 40 mg/l or less; and isotherm studies with several metal concentrations ranging from 10 mg/l to 400 mg/l.
Summary/Accomplishments (Outputs/Outcomes):Metal uptake by unacclimated cultures. The results of this research with test heavy metals of silver, copper, cadmium and lead showed that even dilute biological cultures exhibited removal efficiencies up to 95%. At low metal concentrations (< 50 mg/l), unacclimated cultures removed lead, silver, cadmium, and copper at efficiencies of 23.5, 7.6, 4.1, and 3.7 mg metal/ 100 mg protein, respectively. Much higher uptake efficiencies of up to 210 mg lead/100 mg protein and 360 mg copper/100 mg protein were observed at higher heavy metal concentrations. Aerobic cultures at the low growth rate (m = 1 day-1) removed 50% to 160% more heavy metals than those maintained at the high growth rate (m= 3 day-1). Once it was established that higher metal uptake is obtained with cultures at the lower specific growth rate, all subsequent chemostat cultures were cultivated at a specific growth rate of 1 day-1.
Unacclimated aerobic cultures exhibited the following hierarchy of metal uptake: Cu>Pb>Cd. Aerobic cultures exposed to a mixture of metals removed a higher mass of heavy metals than those observed with single metals. Metal removal efficiencies increased to 30 mg/100 mg protein or higher when lead, copper and cadmium were present in binary or ternary mixtures. In mixed-metal systems, lead uptake decreased, while copper and cadmium uptake increased compared with bioremovals of each of these heavy metals present alone. Chelation of heavy metals by organic ligands was responsible for up to 65% of the total metal uptake by the slow growers. Ion exchange was the next most important mechanism of metal uptake. Adsorption and precipitation together accounted for about 8% of the total metal removal. In contrast, ion exchange was the predominant metal-removal mechanism for fast-growing aerobes. These observations indicated that biopolymers synthesized at these two growth conditions had different stuructural properties.
Anaerobic cultures were also very efficient in removing heavy metals. Copper and cadmium were removed very rapidly from batch cultures (within a few hours after their addition) at efficiencies of 86% and 72%, respectively. In cultures charged with mixed cadmium-copper, cadmium removal increased from 72% to 98%, while copper removal was depressed from 86% to 70% indicating that both synergistic and antagonistic effects could be operative in anaerobic cultures exposed to mixtures of heavy metals. Precipitation was the major metal removal mechanism for the anaerobic culture with ion exchange, adsorption, and chelation playing minor roles in metal uptake.
Metal uptake bv acclimated culture. The acclimated culture was developed by including cadmium in the chemostat feed; this culture was expected to be tolerant (acclimated) to other heavy metals as well by virtue of the phenomenon of cross tolerance. The acclimated culture was considerably less efficient in removing heavy metals than acclimated cultures. Thus, tolerance to heavy metals, which requires transcription of the appropriate operon, could not be established by the presence of the metal inducer alone.
Metal uptake by stimulated cultures. A chemostat culture was developed in the presence of cysteine and cystine to promote the synthesis of metallothioneins or metallothionein-like proteins. Batch metal uptake studies with these "stimulated" cultures showed that lead, copper, and cadmium removals were 18%, 38%, and 88% higher than those effected by the "acclimated" cultures.
Metal uptake by cultures grown in the presence of the inducer. and cvsteine and cvstine. A separate chemostat was operated by including cysteine and cystine (protein precursors) as well as cadmium (inducer) in the continuous feed to achieve the full potential for metallothionein synthesis. At high metal concentrations, this culture exhibited metal removals (37 mg Cd/100 mg protein, 76 mg Cu/100 mg protein, and 2.99 mg Pb/100 mg protein) that were 50% -100% higher that those effected by the stimulated culture. These results showed that synthesis of sulfur-containing proteins can be enhanced substantially by providing their precursors plus a metal inducer in the growth medium.
Metal uptake by cultures grown in the presence of BGP and peptone. BGP and peptone were very effective in increasing metal uptake at concentrations of 40 mg/l. As an example, copper uptake by the test culture grown in the presence of cystine, BGP, and peptone removed nine times as much copper as the unacclimated culture. Cultures grown on peptone alone was more effective than those developed on peptone plus BGP in removing copper and cadmium at high metal concentrations between 100 and 300 mg/l. At these high concentrations, the peptone-grown culture removed about seven times as much copper or cadmium as that removed by the unacclimated culture. The metal removal efficiencies (expressed in terms of percent of dry protein weight) observed in these studies were more than three times those reported in the literature.
Metal uptake kinetics. Copper, lead, and silver were removed rapidly by the unacclimated and stimulated cultures. Cadmium uptake was very slow. Metal uptake followed first-order kinetics. The test culture grown in the presence of cystine and peptone exhibited the highest first-order rate constant of 0.108/hr for copper uptake. The culture grown in the presence of cystine, BGP, and peptone had the highest first-order constant of 0.031/hr for cadmium uptake.
Culture viability. Unacclimated cultures as well as cultures grown in the presence of cystine experienced almost complete loss of viability and Iysis at metal concentrations of 30 mg/1 or higher. Conversely, cultures grown in the presence of BGP and peptone did not experience a complete loss in viability, and there was regrowth of some species after a period of declining population density. The Iysed cultures were effective in removing heavy metals at high efficiencies indicating that biopolymers, and not intact cells, were primarily responsible for metal removal.
The results have been presented at professional meetings and to interested parties.
Journal Articles on this Report: 2 Displayed | Download in RIS Format
| Other subproject views: | All 7 publications | 4 publications in selected types | All 2 journal articles |
| Other center views: | All 900 publications | 231 publications in selected types | All 188 journal articles |
| Type | Citation | ||
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Ghosh S, Bupp S. Stimulation of biological uptake of heavy-metals. Water Science and Technology 1992;26(1-2):227-236. |
R825549C018 (Final) |
not available |
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Ghosh S, Bupp S. Heavy metal removal by Iysing cells of acclimated and stimulated aerobic cultures. Biotechnology and Bioengineering 1991. |
R825549C018 (Final) |
not available |
heavy metals, protein complexation, biopolymers, chelation, ion exchange. , Water, Geographic Area, Scientific Discipline, Waste, RFA, Remediation, Analytical Chemistry, Chemistry, Hazardous Waste, EPA Region, Environmental Chemistry, Contaminated Sediments, Hazardous, Ecology and Ecosystems, Geochemistry, heavy metal contamination, heavy metals, bioploymers, fate and transport, fate and transport , soil and groundwater remediation, mining wastes, groundwater, contaminated sediment, hazardous wate, contaminant transport, Region 8, contaminated soil, bioremediation of soils, bioremediation, contaminated groundwater, groundwater remediation, sediment treatment, Region 7
Relevant Websites:
Progress and Final Reports:
Original Abstract
Main Center Abstract and Reports:
R825549 HSRC (1989) - Great Plains/Rocky Mountain HSRC
Subprojects under this Center:
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
R825549C006 Fate of Trichloroethylene (TCE) in Plant/Soil Systems
R825549C007 Experimental Study of Stabilization/Solidification of Hazardous Wastes
R825549C008 Modeling Dissolved Oxygen, Nitrate and Pesticide Contamination in the Subsurface Environment
R825549C009 Vadose Zone Decontamination by Air Venting
R825549C010 Thermochemical Treatment of Hazardous Wastes
R825549C011 Development, Characterization and Evaluation of Adsorbent Regeneration Processes for Treament of Hazardous Waste
R825549C012 Computer Method to Estimate Safe Level Water Quality Concentrations for Organic Chemicals
R825549C013 Removal of Nitrogenous Pesticides from Rural Well-Water Supplies by Enzymatic Ozonation Process
R825549C014 The Characterization and Treatment of Hazardous Materials from Metal/Mineral Processing Wastes
R825549C015 Adsorption of Hazardous Substances onto Soil Constituents
R825549C016 Reclamation of Metal and Mining Contaminated Superfund Sites using Sewage Sludge/Fly Ash Amendment
R825549C017 Metal Recovery and Reuse Using an Integrated Vermiculite Ion Exchange - Acid Recovery System
R825549C018 Removal of Heavy Metals from Hazardous Wastes by Protein Complexation for their Ultimate Recovery and Reuse
R825549C019 Development of In-situ Biodegradation Technology
R825549C020 Migration and Biodegradation of Pentachlorophenol in Soil Environment
R825549C021 Deep-Rooted Poplar Trees as an Innovative Treatment Technology for Pesticide and Toxic Organics Removal from Soil and Groundwater
R825549C022 In-situ Soil and Aquifer Decontaminaiton using Hydrogen Peroxide and Fenton's Reagent
R825549C023 Simulation of Three-Dimensional Transport of Hazardous Chemicals in Heterogeneous Soil Cores Using X-ray Computed Tomography
R825549C024 The Response of Natural Groundwater Bacteria to Groundwater Contamination by Gasoline in a Karst Region
R825549C025 An Electrochemical Method for Acid Mine Drainage Remediation and Metals Recovery
R825549C026 Sulfide Size and Morphology Identificaiton for Remediation of Acid Producing Mine Wastes
R825549C027 Heavy Metals Removal from Dilute Aqueous Solutions using Biopolymers
R825549C028 Neutron Activation Analysis for Heavy Metal Contaminants in the Environment
R825549C029 Reducing Heavy Metal Availability to Perennial Grasses and Row-Crops Grown on Contaminated Soils and Mine Spoils
R825549C030 Alachlor and Atrazine Losses from Runoff and Erosion in the Blue River Basin
R825549C031 Biodetoxification of Mixed Solid and Hazardous Wastes by Staged Anaerobic Fermentation Conducted at Separate Redox and pH Environments
R825549C032 Time Dependent Movement of Dioxin and Related Compounds in Soil
R825549C033 Impact of Soil Microflora on Revegetation Efforts in Southeast Kansas
R825549C034 Modeling the use of Plants in Remediation of Soil and Groundwater Contaminated by Hazardous Organic Substances
R825549C035 Development of Electrochemical Processes for Improved Treatment of Lead Wastes
R825549C036 Innovative Treatment and Bank Stabilization of Metals-Contaminated Soils and Tailings along Whitewood Creek, South Dakota
R825549C037 Formation and Transformation of Pesticide Degradation Products Under Various Electron Acceptor Conditions
R825549C038 The Effect of Redox Conditions on Transformations of Carbon Tetrachloride
R825549C039 Remediation of Soil Contaminated with an Organic Phase
R825549C040 Intelligent Process Design and Control for the Minimization of Waste Production and Treatment of Hazardous Waste
R825549C041 Heavy Metals Removal from Contaminated Water Solutions
R825549C042 Metals Soil Pollution and Vegetative Remediation
R825549C043 Fate and Transport of Munitions Residues in Contaminated Soil
R825549C044 The Role of Metallic Iron in the Biotransformation of Chlorinated Xenobiotics
R825549C045 Use of Vegetation to Enhance Bioremediation of Surface Soils Contaminated with Pesticide Wastes
R825549C046 Fate and Transport of Heavy Metals and Radionuclides in Soil: The Impacts of Vegetation
R825549C047 Vegetative Interceptor Zones for Containment of Heavy Metal Pollutants
R825549C048 Acid-Producing Metalliferous Waste Reclamation by Material Reprocessing and Vegetative Stabilization
R825549C049 Laboratory and Field Evaluation of Upward Mobilization and Photodegradation of Polychlorinated Dibenzo-P-Dioxins and Furans in Soil
R825549C050 Evaluation of Biosparging Performance and Process Fundamentals for Site Remediation
R825549C051 Field Scale Bioremediation: Relationship of Parent Compound Disappearance to Humification, Mineralization, Leaching, Volatilization of Transformaiton Intermediates
R825549C052 Chelating Extraction of Heavy Metals from Contaminated Soils
R825549C053 Application of Anaerobic and Multiple-Electron-Acceptor Bioremediation to Chlorinated Aliphatic Subsurface Contamination
R825549C054 Application of PGNAA Remote Sensing Methods to Real-Time, Non-Intrusive Determination of Contaminant Profiles in Soils
R825549C055 Design and Development of an Innovative Industrial Scale Process to Economically Treat Waste Zinc Residues
R825549C056 Remediation of Soils Contaminated with Wood-Treatment Chemicals (PCP and Creosote)
R825549C057 Effects of Surfactants on the Bioavailability and Biodegradation of Contaminants in Soils
R825549C058 Contaminant Binding to the Humin Fraction of Soil Organic Matter
R825549C059 Identifying Ground-Water Threats from Improperly Abandoned Boreholes
R825549C060 Uptake of BTEX Compounds by Hybrid Poplar Trees in Hazardous Waste Remediation
R825549C061 Biofilm Barriers for Waste Containment
R825549C062 Plant Assisted Remediation of Soil and Groundwater Contaminated by Hazardous Organic Substances: Experimental and Modeling Studies
R825549C063 Extension of Laboratory Validated Treatment and Remediation Technologies to Field Problems in Aquifer Soil and Water Contamination by Organic Waste Chemicals