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Biotechnology and the Environment
Environment – describes everything that surrounds a particular organism
• Other organisms• Soil, air, water• Temperature, humidity, radiation
Environmental Biotechnology - the development, use and regulation of
biological systems for remediation of
contaminated environments (land, air,
water), and for environment-friendly
processes.Bioremediation - the use of
microorganisms to remedy
environmental problems
Biotechnology and the Environment
What are the events that triggered the interest in environmental biotechnology?
•Rachel Carlson’s Silent Spring (DDT)
•Love Canal
•Burning of a River
•Exxon Valdez in 1989
Biotechnology and the Environment
What do they all have in common?• The advent of the Industrial Revolution
• increase in products and waste• people moved to the city• increase in human population
Biotechnology and the Environment
Regulations were passed:• Resource Conservation and Recovery Act (1976)
• Must identify hazardous waste and establish standards for managing it properly
• Requires companies that store, treat or dispose to have permits stating how the wastes are to be managed
• Record of its travels: Chain of Custody
• EPA initiates the Superfund Program (1980) • Counteract careless and negligent practices
• Environmental Genome Project• Study and understand the impacts of environmental
chemicals on human diseases
Biotechnology and the Environment
Waste• Solid: landfills, combustion-including waste-to
energy plants, recovery• slurries, composting
• Liquid: septic: sewage treatment, deep-well injection
• Gas: fossil fuels, chlorofluorocarbons
• Hazardous –anything that can explode, catch fire, release toxic fumes, and particles or cause corrosion
Biotechnology and the Environment
Garbage TestBanana PeelWood
Scrap/SawdustWax PaperStyrofoam CupTin CanAluminum Soda CanPlastic CartonGlass Bottles
0.5 Years4 Years5 Years20 Years100 Years500 Years500 Years>500 Years
Biotechnology and the Environment
There is no waste in Nature:
From rocks and soil to plants and animals to air and water and back again:
Recycled largely byMicrobes
Biogeochemical Cycles are a major part of the recycling process
Carbon Cycle: The primary biogeochemical cycle organic cmpds CO2 and back
Nitrogen Cycle: proteins amino acids NH3NO2
-NO3-NO2
-N2ON2 NH3 etc_
Sulfur Cycle: Just like the nitrogen cycle, numerous oxidation states. Modeled in the Winogradsky column
Phosphorous Cycle: Doesn’t cycle between numerous oxidation states only soluble and insoluble form
Nitrogen Cycle
N2
NO3-
NO2-
NO2- NH3
Denitrificationnitrobacter
Nitrificationnitrosomas
PseudomonasBacillusParacoccus
leguminous
decomposition Fixation
ammonification
cyanobacteria
Phosphorus Cycle
Sea simplePhosphates
Phosphaterocks
Phosphates too complexfor plants to absorbfrom the soilMicrobes Breakdown
complex compounds
Scientists learn from nature in the 1980’s• The concept of Gaia –the total world is a living
organism and what nature makes nature can degrade (bioinfalibility); only man makes xenobiotic compounds
• Clean up pollution-short and long term solutions (cost, toxicity, time frame)
• Use compounds that are biodegradable• Produce Energy and Materials in less destructive ways• Monitor Environmental Health• Increase Recovery of Minerals and Oil
Biotechnology and the Environment
Bioremediation finds its place• Companies begin to specialize in cleaning up toxic waste
spills by using a mixture of bacteria and fungi because cleaning these spills usually requires the combined efforts of several strains.
• Biotechnologists begin engineering “super bugs” to clean up wastes.
• However, there are many microorganisms in nature that will degrade waste products.
Biotechnology and the Environment
Bioremediation Basics
Naturally occurring marshes and wetlands have been doing the job!
What Needs to be Cleaned UP?• Everything!• How do pollutants enter the environment?
• Runoff, leachates, air
• SO How bioremediation is used depends on 1)what is contaminated? (locations)2)on the types of chemicals that need to be cleaned up3)the concentration of the contaminants (amount and
duration)
Chemicals in the environment• Sewage (by products of medicines and food we
eat such as estrogen (birth control pills) and caffeine (coffee)
• Products around the house (perfumes, fertilizers, pesticides, medicines)
• Industrial• Agricultural
Bioremediation Basics
Bioremediation Basics
Fundamentals of Cleanup Reactions• Microbes can convert many chemicals
into harmless compounds HOW?• Aerobic or anaerobically• Both involve oxidation and reduction
reactions
Bioremediation Basics
Fundamentals of Cleanup Reactions• Oxidation and Reduction Reactions
• Oxidation involves the removal of one or more electrons
• Reduction involves the addition of one or more electrons
• Oxidizing agents gain electrons and reducing agents lose electrons
• The rxns are usually coupled and the paired rxns are known are redox reactions
Bioremediation Basics
Aerobic and anaerobic biodegradation• Aerobic
• Oxygen is reduced to water and the organic molecules (e.g. petroleum, sugar) are oxidized
• Anaerobic• An inorganic compound is
reduced and the organic molecules are oxidized (e.g. nitrate is reduced and sugar is oxidized)
• NOTE: Many microbes can do both aerobic and anaerobic respiration; the process which produces the most ATP is used first!
The Players: Metabolizing Microbes• Site usually contains a variety of microbes• Closest to the contaminant: anaerobes• Farthest away: aerobes• The most common and effective bacteria are the indigenous
microbes (e.g. Pseudomonas in soil)• Fungus and algae are also present in the environment and do a
good job of “cleaning up” chemicals (fungi do it better than bacteria)
Bioremediation Basics
Bioremediation Genomics Programs• Stimulating Bioremediation
• Add fertilizers (nutrient enrichment) to stimulate the growth of indigenous microorganisms • Adding bacteria or fungus to assist indigenous microbes is known as bioaugumentation or seeding
Bioremediation Basics
Phytomediation• Utilizing plants to clean up chemicals
• Ex: cottonwoods, poplar, juniper trees, grasses, alfalfa• Low cost, low maintenance and it adds beauty to the site
Bioremediation Basics
Cleanup Sites and Strategies
Do the chemicals pose a fire or explosive hazard? Do the chemicals pose a threat to human health
including the health of clean-up workers? (what happened at Chernobyl to the workers?)
Was the chemical released into the environment through a single incident or was there long-term leakage from a storage container?
Where did the contamination occur? Is the contaminated area at the surface of the
soil? Below ground? Does it affect water? How large is the contaminated area?
Cleanup Sites and Strategies
Soil Cleanup• Either remove it (ex situ bioremediation) or in situ
(in place)• In place:
• If aerobic may require bioventing• Most effective in sandy soils
• Removed:• Slurry-phase, solid phase, composting, landfarming,
biopiles
Environmental Diagnostics
A promising new area of research involves using living organisms to detect and assess harmful levels of toxic chemicals.
When healthy Daphnia are fed a sugar substrate (-galactoside attached to a fluorescent marker), they metabolize the sugar and fluoresce under UV light.
When Daphnia are stressed by toxins, they do not have the enzymatic ability to digest the sugar and therefore do not fluoresce under UV light.
Environmental Diagnostics
Toxicity reduction involves adding chemicals to hazardous waste in order to diminish the toxicity.• For example, if the toxicity results from heavy
metals, EDTA will be added to the waste and the effluent will be tested again to determine if the toxicity has been acceptably reduced.
• EDTA chelates (binds to) metals, thereby making them unavailable to harm organisms in a particular body of water.
Environmental Diagnostics
Petroleum eating bacteria• Ananda Chakrabarty at General Electric
Heavy metals (bioaccumulation)• Bacteria sequester heavy and radioactive
metalsBiosensors
• lux genes
Applying Genetically Engineered Strains to Clean Up the Enviroment
The Exxon Valdez Oil Spill• In the end, the indigenous microbes did the best
job
Oil Fields of Kuwait• Poses a problem due to the environmental
conditions
Environmental Disasters: Case Studies in Bioremediation
Microbial geneticsNew types of microbes (from the ocean etc)Radioactive materials DO A BETTER JOB OF DETERMINING RISK
and ASSESSMENT OF EXISTING SITES
Future Strategies and Challenges for Bioremediation