Applications of Modern Biotechnology in the Environment

Applications of Modern Biotechnology in the Environment

• Biotechnology processes can improve the environment
• Organisms were developed during the Gulf War to consume oil
• Organisms are used in gold mining to consume contaminants
• Microorganisms like bacteria and fungi naturally break down contaminants into less harmful forms
• Environmental pollution sources include industrial waste, accidental/intentional spills of oil and chemicals, radioactive substances, pesticides, and burnt waste releasing chemicals into the air.
• Common pollutants include acetone, benzene, carbon tetrachloride, cyanide, DDT, DDE, detergents, mercury, toluene, vinyl chloride.
• Sources of these pollutants vary from plastics, fibers, solvents, and other chemicals.
• Bioremediation is the process of using organisms to convert hazardous pollutants into less toxic compounds.
• Bioremediation involves manipulating the process of compound degradation through biological activity.
• It's an ongoing research area since the 1940s.
• Key players in bioremediation include: bacteria, fungi, algae, and plants.
• Microbes reside in soil, water, air, animals, plants, and rocks. A single teaspoon of garden soil contains millions of bacteria and thousands of fungi & algae.

Why Bioremediation?

• Bioremediation uses natural processes, such as bacteria, to transform pollutants.
• It doesn't just move pollutants from one environment to another.
• Bioremediation is the most economical solution for pollutant removal.
• Degradation products are typically harmless, such as alcohol, phenols, esters, ketones, & fatty acids, which convert into carbon dioxide, water, etc and don't harm the environment.

Advantages of Bioremediation

• Highly specific
• Less expensive than other methods
• Complete degradation and clean up when a mineralization occurs
• Does not transfer contaminants from one environment to another
• Uses a natural process
• Good public acceptance
• Simple process

Disadvantages of Bioremediation

• Not instantaneous
• Often requires system development and empirical optimization (cannot use computer models)
• May have inhibitors present
• Pollutants may not be in a biodegradable form (polymers, plastics)
• Pollutants may be recalcitrant (higher congeners of PCBs)

Strategies for Bioremediation

• Different strategies are employed depending on the environment (soil, aquatic, etc.)
• Aquatic environments include fresh water, marine waters, groundwater sources, and wastewater treatment facilities.

Examples of Bioremediation Applications

• Microbial remediation of oil spills (hundreds recorded since 1970; 448 recorded between 1990 and 2013).
• Exxon Valdez oil spill (1989) in Prince William Sound, Alaska is an example
• Bioremediation is commonly applied in sewage treatment.

Classes of Bioremediation for Soil

• In situ bioremediation treats contaminated material at the site.
• Ex situ bioremediation removes contaminated material for treatment elsewhere.
• Technologies include landfarming, bioreactors, composting, bioaugmentation, and biostimulation.

Bioaugmentation, Biostimulation, Bioventing

• Bioaugmentation: introduces natural or genetically engineered microorganisms to enhance bioremediation
• Biostimulation: modifies the environment (e.g., adds nutrients like phosphorus, nitrogen, or carbon) to stimulate existing microorganisms.
• Bioventing: increases available oxygen (similar to biostimulation) by introducing air or hydrogen peroxide.

Landfarming

• Biological degradation of waste by incorporating it into the soil.
• Relies on healthy soil microorganisms to metabolize waste components.
• Waste is rendered safer (but not necessarily completely safe).

Factors to consider in bioremediation

• Temperature
• Inorganic nutrient availability
• pH level
• Heavy metal concentration
• Depending on the environment, the effective organisms/processes will differ

Types of Environments suited for Bioremediation

• Different organisms are effective using different temperatures ranging from cold (0°C-15°C) psychrophilic organisms in cold environments to hot (>45°C) environments needing thermophilic organisms
• Warmer environments have generally faster degradation rates.

Genetic engineering in bioremediation

• Controversial due to potential alteration of the environment by releasing genetically engineered organisms
• May lead to mutated organisms, competing with naturally occurring microbes.
• Genetically engineered microorganisms would compete with microbes naturally present at the polluted site.

Mycoremediation

• Fungi are used for bioremediation.
• Chemicals that fungi can treat include pentachlorophenols, asbestos, heavy metals, sewage, PCBs.
• Organisms used include: Fusarium oxysporum, Mortierella spp., and Phanerochaete spp.

Phytoremediation

• Bioremediation process employing plants
• Plants absorb and metabolize chemicals through their roots.
• Effective when contaminants are near the surface.
• Known as carbon sinks and help in reducing air pollution and greenhouse gases.

Bio-Enrich

• A mix of natural microbial flora and enzymes for bio-degradation of industrial waste and pollutants.
• Effectively reduces COD and BOD.
• Microbial biotechnology-based.

Other Notes

• "Electric bacteria" are used in purifying sewage water.
• "Super-enzyme" proteins derived from bacteria treat plastics.
• Algae and fungal mycelium are potentially used as bioplastics.