Bioremediation Chapter 9. Biotechnology and the Environment Environment – describes everything that surrounds a particular organism Other organisms

Bioremediation

Chapter 9

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


The advent of the Industrial Revolution • increase in products and waste• people moved to the city• increase in human population


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


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


Waste• Solid: landfills, combustion-including waste-to

energy plants, recovery• slurries, composting, combustion

• 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


Garbage TestBanana PeelWood

Scrap/SawdustWax PaperStyrofoam CupTin CanAluminum Soda CanPlastic CartonGlass Bottles

0.5 Years4 Years5 Years20 Years100 Years500 Years500 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 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

Carbon Cycle

CO2

Organic compounds

Nitrogen Cycle

N2

NO3-

NO2-

NO2- NH3

Denitrificationnitrobacter

Nitrificationnitrosomas

PseudomonasBacillusParacoccus

leguminous

decomposition Fixation

ammonification

cyanobacteria

Sulfur Cycle

H2SO4

SO2Atmosphere

Organic sulfur

S SO4

H2S

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


Bioremediation Basics

Naturally occurring marshes and wetlands have been doing the job!

What Needs to be Cleaned UP?• Everything!• 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)

How do pollutants enter 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 – leaching into groundwater• Agricultural - pesticides



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.



Fundamentals of Cleanup Reactions• Microbes can convert many chemicals

into harmless compounds HOW?• Aerobic or anaerobically• Both involve oxidation and reduction

reactions


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


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 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


Phytoremediation• 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?


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


Bioremediation of Water• Wastewater treatment


Bioremediation of Water• Groundwater Cleanup


Turning Wastes into Energy• Biogas-a gas produced by the biological

breakdown of organic matter in the absence of oxygen

Video describing potential for biogas production from animal manure


Turning Wastes into Energy• Cowpower:

• Compare 3.0 kwh of “cow power” available in one cow’s daily manure contribution with the 2.4 kwh necessary to burn a 100 w light bulb for a day

Heavy metals (bioaccumulation)• Bacteria sequester heavy and radioactive

metalsPetroleum eating bacteria

• Ananda Chakrabarty at General ElectricBiosensors

• lux genes

Applying Genetically Engineered Strains to Clean Up the Environment

Environmental Diagnostics

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

Daphnia magna

Transparent Thorax and Abdomen


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.


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.


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)DO A BETTER JOB OF DETERMINING RISK

and ASSESSMENT OF EXISTING SITES

Future Strategies and Challenges for Bioremediation

Biodegradation• Wastewater treatment plants, organic farming

Bioremediation• Environmental clean-up companies, labs

developing super bugsBiocatalysis

• Plastics, degradable and recyclable productsOther

• Mining companies, oil companies

Careers in Environmental Biotech

Documents

Bioremediation Chapter 9. Biotechnology and the Environment Environment – describes everything that surrounds a particular organism Other organisms