Chapter 9 Bioremediation

Biotechnology and the Environment Environment – describes everything that surrounds a particular organism Other organisms Soil, air, water Temperature, humidity, radiation

Biotechnology and the Environment 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 Test Banana Peel Wood Scrap/Sawdust Wax Paper Styrofoam Cup Tin Can Aluminum Soda Can Plastic Carton Glass Bottles 0.5 Years 4 Years 5 Years 20 Years 100 Years 500 Years >500 Years

There is no waste in Nature: From rocks and soil to plants and animals to air and water and back again: Recycled largely by Microbes

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 NH3NO2-NO3-NO2-N2ON2 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

Carbon Cycle CO2 Organic compounds

Nitrogen Cycle N2 cyanobacteria leguminous decomposition Fixation ammonification NH3 NO2- nitrosomas Nitrification Pseudomonas Bacillus Paracoccus NO2- Denitrification nitrobacter NO3-

Sulfur Cycle Atmosphere SO2 H2SO4 Organic sulfur S SO4 H2S

Phosphorus Cycle Sea simple Phosphates Phosphate rocks Phosphates too complex for plants to absorb from the soil Sea simple Phosphates Phosphate rocks Microbes Breakdown complex compounds

Biotechnology and the Environment 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.

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 what is contaminated? (locations) on the types of chemicals that need to be cleaned up the concentration of the contaminants (amount and duration)

Bioremediation Basics 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 Some are known to be potential carcinogens and mutagens

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 Example: Na + Cl2  NaCl reduced +1 -1 oxidized

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!

Bioremediation Basics 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

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

Cleanup Sites and Strategies Bioremediation of Water Wastewater treatment

Cleanup Sites and Strategies Bioremediation of Water Groundwater Cleanup

Environmental Diagnostics A promising new area of research involves using living organisms to detect and assess harmful levels of toxic chemicals.

Environmental Diagnostics Daphnia magna Transparent Thorax and Abdomen

Environmental Diagnostics When healthy Daphnia are fed a sugar substrate (-galactoside attached to a fluorescent marker), they metabolize the sugar and fluoresce under UV light. Environmental Diagnostics                                                                                                                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.

Applying Genetically Engineered Strains to Clean Up the Enviroment Petroleum eating bacteria Ananda Chakrabarty at General Electric Heavy metals (bioaccumulation) Bacteria sequester heavy and radioactive metals Biosensors lux genes

Environmental Disasters: Case Studies in Bioremediation 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

Future Strategies and Challenges for Bioremediation Microbial genetics New types of microbes (from the ocean etc) Radioactive materials DO A BETTER JOB OF DETERMINING RISK and ASSESSMENT OF EXISTING SITES

Careers in Environmental Biotech Biodegradation Wastewater treatment plants, organic farming Bioremediation Environmental clean-up companies, labs developing super bugs Biocatalysis Plastics, degradable and recyclable products Other Mining companies, oil companies