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Copyright © 2009 Pearson Education, Inc.
Bioremediation
Copyright © 2009 Pearson Education, Inc.
What Is Bioremediation?
• Biodegradation - the use of living organisms such as bacteria, fungi, and plants to degrade chemical compounds
• Bioremediation – process of cleaning up environmental sites contaminated with chemical pollutants by using living organisms to degrade hazardous materials into less toxic substances
Copyright © 2009 Pearson Education, Inc.
What Is Bioremediation?
• 1980 Superfund Program established by U.S. Congress– Initiative of the U.S. Environmental Protection Agency
(EPA)– To counteract careless and even negligent practices of
chemical dumping and storage, as well as concern over how these pollutants might affect human health and the environment
– Purpose is to locate and clean up hazardous waste sites
Copyright © 2009 Pearson Education, Inc.
What Is Bioremediation?
• Environmental Genome Project – Purpose is to study and understand the impacts of
environmental chemicals on human disease
• Why use bioremediation?– Most approaches convert harmful pollutants into
relatively harmless materials such as carbon dioxide, chloride, water, and simple organic molecules
– Processes are generally cleaner
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What Is Bioremediation?
• Biotechnological approaches are essential for– Detecting pollutants– Restoring ecosystems – Learning about conditions that can result in human
diseases – Converting waste products into valuable energy
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Bioremediation Basics
• What needs to be cleaned up?– Soil, water, air, and sediment
• Pollutants enter environment in many different ways– Tanker spill, truck accident, ruptured chemical tank at
industrial site, release of pollutants into air
• Location of accident, the amount of chemicals released, and the duration of the spill impacts the parts of the environment affected
Copyright © 2009 Pearson Education, Inc.
Bioremediation Basics
Copyright © 2009 Pearson Education, Inc.
Bioremediation Basics
• Chemicals in the Environment– Carcinogens – Mutagens– Cause skin rashes, birth defects– Poison plant and animal life
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Bioremediation Basics
Copyright © 2009 Pearson Education, Inc.
Bioremediation Basics
• Fundamentals of Cleanup Reactions– Microbes convert chemicals into harmless substances by
either• Aerobic metabolism (require oxygen) or anaerobic
metabolism (do not require oxygen)
Copyright © 2009 Pearson Education, Inc.
Bioremediation Basics
• Aerobic and Anaerobic Biodegradation
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Bioremediation Basics
• The Players: Metabolizing Microbes– Indigenous microbes – those found naturally at a polluted site– Bacteria
• Pseudomonas• E.coli
– Algae and fungi• Phanerochaete chrysosporium• Phanerochaete sordida• Fusarium oxysporum• Mortierella hyaline
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Bioremediation Basics
• Stimulating Bioremediation– Nutrient enrichment (fertilization) – fertilizers are added
to a contaminated environment to stimulate the growth of indigenous microorganisms that can degrade pollutants
– Bioaugmentation (seeding) –bacteria are added to the contaminated environment to assist indigenous microbes with biodegradative processes
Copyright © 2009 Pearson Education, Inc.
Cleanup Sites and Strategies
• Soil Cleanup– Ex situ bioremediation
• Slurry phase bioremediation
• Solid phase bioremediation
– Composting
– Land farming
– Biopiles
– In situ bioremediation• Bioventing – pumping either air or hydrogen peroxide into
the contaminated soil
Copyright © 2009 Pearson Education, Inc.
Cleanup Sites and Strategies
Copyright © 2009 Pearson Education, Inc.
Cleanup Sites and Strategies
• Bioremediation of Water– Wastewater treatment– Groundwater cleanup
Copyright © 2009 Pearson Education, Inc.
Cleanup Sites and Strategies
Copyright © 2009 Pearson Education, Inc.
Cleanup Sites and Strategies
Copyright © 2009 Pearson Education, Inc.
Cleanup Sites and Strategies
• Turning Wastes into Energy– Methane gas used to produce electricity– Soil nutrients can be sold commercially as fertilizers– Anaerobes in sediment that use organic molecules to
generate energy• Electicigens – electricity-generating microbes
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Cleanup Sites and Strategies
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Applying Genetically Engineered Strains to Clean Up the Environment
• Petroleum-Eating Bacteria– Created in 1970s– Isolated strains of pseudomonas from contaminated soils– Contained plasmids that encoded genes for breaking
down the pollutants
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Applying Genetically Engineered Strains to Clean Up the Environment
• E. coli to clean up heavy metals– Copper, lead, cadmium, chromium, and mercury
• Biosensors – bacteria capable of detecting a variety of environmental pollutants
• Genetically Modified Plants and Phytoremediation– Plants that can remove RDX and TNT
Copyright © 2009 Pearson Education, Inc.
Environmental Disasters: Case Studies in Bioremediation
• Jet Fuel and Hanahan, South Carolina• The Exxon Valdez Oil Spill• Oil Fields of Kuwait• BP Oil Spill in Gulf of Mexico
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Future Strategies and Challenges for Bioremediation
• Recovering Valuable Metals• Bioremediation of Radioactive Wastes
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