Industrial & Environmental Biotechnology Final Review

What is environmental biotechnology?

The management of microbial communities to provide environmental services, particularly for detoxifying contaminated water/soil and converting biomass energy to usable forms.

What are the four main aspects of environmental biotechnology?

1. Bioremediation

2. Prevention

3. Detection and Monitoring

4. Genetic Engineering

How do enzymes improve industrial processes environmentally?

Enzymes are non-toxic, biodegradable, work at moderate temperatures, have fewer side reactions, and are more economical in energy/resource consumption compared to chemical alternatives.

What is the role of biosensors in environmental biotechnology?

Biosensors combine biological and electronic devices to detect pollution incidents and continuously monitor pollutants in environments.

What are the five stages of biofilm formation?

1. Initial attachment

2. Irreversible attachment

3. Microcolony formation (maturation I)

4. Maturation II

5. Dispersion

What is a Membrane Biofilm Reactor (MBfR)?

A treatment technology using gas-transferring membranes that supply gaseous electron donors/acceptors (oxygen, hydrogen, methane) to biofilms that form on the membrane surface.

What is a Microbial Fuel Cell (MFC)?

A technology that uses electroactive biofilms to generate electricity while simultaneously cleaning wastewater or treating other pollutants.

What are the two types of electron transfer in Microbial Fuel Cells?

1. Direct Transfer (DET): Bacteria transfer electrons directly to the electrode

2. Indirect Transfer: Electrons move via intermediate shuttle molecules

What are EPS in biofilms?

Extracellular Polysaccharides - gel-like substances produced by bacterial cells that form the protective matrix of biofilms, aiding in attachment and stability.

What key factors influence biofilm formation?

Quorum sensing molecules, extracellular polysaccharides (EPS), lipopolysaccharides (LPS), and environmental factors (pH, salinity, heavy metals, nutrients).

What is the advantage of MABR (Membrane Aerated Biofilm Reactor)?

MABRs provide oxygen more efficiently, reducing energy costs (which can be up to 70% of total energy costs in traditional systems) and enable simultaneous aerobic/anaerobic processes.

How does Quorum Sensing affect biofilms?

Quorum sensing is a cell-to-cell communication mechanism where bacteria release autoinducers, coordinating their collective behavior and regulating biofilm formation and structure.

What are some biotechnological solutions to pollution problems?

Adding phytase to animal feed (reduces phosphate in manure), biomining of metals (saves energy, reduces waste), and genetically modified bacteria for cleaner production processes.

What are traditional methods for monitoring environmental pollution?

Counting plant/animal/microbial species and individuals, analyzing levels of oxygen/methane in water, and measuring faecal indicator bacteria through colony-forming units (CFU).

What is the relationship between EPS and electron transfer in biofilms?

EPS influences surface charge, provides anchoring for proteins involved in electron transfer, and can contain conductive components that facilitate electron movement through the biofilm.

Define environmental biotechnology according to the International Society for Environmental Biotechnology.

The development, use and regulation of biological systems for remediation of contaminated environments (land, air, water), and for environment-friendly processes (green manufacturing technologies and sustainable development).

What is the key science underlying environmental biotechnology?

Microbial ecology, which has advanced rapidly through genomics-based techniques to characterize microbial communities.

What are the three key words/aspects of environmental biotechnology?

Development, Use, and Regulation.

Define bioremediation.

The use of biological systems for the reduction of pollution from air or from aquatic or terrestrial systems.

What are the main functions of bioremediation?

1) Complete mineralization of organic pollutants

2) Partial transformation of pollutants

3) Alteration of pollutant mobility

4) Treatment of contaminated media (water, soil, subsurface material)

What is the electron acceptor in aerobic bioremediation?

Oxygen

What types of pollutants is aerobic bioremediation most effective for?

Petroleum, polyaromatic hydrocarbons (PAHs), phenols, and other reduced pollutants.

What types of contaminants is anaerobic bioremediation used to treat?

Chlorinated ethenes (PCE, TCE, DCE, VC), chlorinated ethanes (TCA, DCA), chloromethanes (CT, CF), chlorinated cyclic hydrocarbons, energetics (perchlorate, RDX, TNT), and nitrate.

Why can't heavy metals be treated through typical biodegradation?

Heavy metals (cadmium, chromium, lead, uranium) cannot be biodegraded - they must be removed through other mechanisms.

What are the mechanisms by which microorganisms help with heavy metal remediation?

Cell surface adsorption, bioaccumulation, electrostatic interactions, surface complexation, ion exchange, precipitation, and intracellular ligands.

How do biofilms compare to planktonic cells in heavy metal removal efficiency?

Biofilms have much higher efficiency (91.71-95.39%) compared to planktonic cells (4.79-10.25%).

What is co-metabolism in bioremediation?

When microorganisms use metabolic pathways normally used for growth and energy to break down pollutant molecules without direct benefit to the organism.

What are the two main approaches to soil and land treatment?

1) In situ (in original place): bioaugmentation, ventilation, bio-stimulation

2) Ex situ (elsewhere): removing soil and groundwater for above-ground treatment

What are the two main stages of wastewater treatment?

1) Primary treatment (sedimentation stage)

2) Secondary treatment (biological stage using bacteria to consume contaminants)

What is activated sludge in wastewater treatment?

A biological process where tanks are seeded with sludge from the previous generation of activation, used to oxidize carbonaceous and nitrogenous matter and remove nutrients.

List the sequential redox zones established in underground water bioremediation (from highest to lowest energy).

1) Aerobic respiration (O₂ → H₂O)

2) Nitrate reduction (NO₃⁻ → N₂)

3) Manganese reduction (MnO₂ → Mn²⁺)

4) Iron reduction (Fe³⁺ → Fe²⁺)

5) Sulfate reduction (SO₄²⁻ → H₂S)

6) Methanogenesis (CO₂ → CH₄)

What are culture-dependent methods for characterizing microbiomes?

Methods using selective media (like TSI Agar slant tubes) to grow and identify microorganisms.

What are culture-independent methods for characterizing microbiomes?

Molecular techniques including DNA/RNA extraction and analysis through methods like metagenomics, proteogenomics, DNA microarrays, and various genetic fingerprinting techniques.

Name three types of air and waste gas treatment systems.

1) Compost-filled filters

2) Bioscrubbers (pollutants washed out using cell suspension) 3) Biotrickling filters (pollutants degraded by immobilized microorga

What famous environmental disaster was treated with bioremediation by adding nutrients?

The 1989 Exxon Valdez oil spill that contaminated 1000 miles of Alaskan shoreline.

What is the current trend in bioremediation approaches?

Evaluating the speed of unaided biodegradation first and acting only when there's insufficient natural activity to remove pollutants quickly enough to prevent risks.

What are the four key aspects of environmental biotechnology?

1. Bioremediation

2. Prevention

3. Detection and Monitoring

4. Genetic Engineering

What is environmental biotechnology?

The management of microbial communities to provide services to society, including detoxifying contaminated water and soil and converting biomass energy to usable forms.

What is bioremediation?

The use of living organisms (typically microorganisms) to degrade, detoxify, or remove pollutants from contaminated environments.

Why are enzymes advantageous in industrial processes?

They are non-toxic, biodegradable, work at moderate temperatures and mild conditions, have fewer side reactions, and are more energy-efficient than traditional chemical processes.

What is an example of product innovation in environmental biotechnology?

Bioplastics made from renewable resources instead of fossil fuels, or genetically modified crops like amylose-free potatoes.

What is "end-of-pipe" treatment?

A conventional approach that focuses on treating waste streams after they've been produced, rather than preventing pollution at the source.

What is a colony-forming unit (CFU)?

A unit used to estimate the number of viable bacteria or fungal cells in a sample by counting colonies that form on a culture medium.

Name three traditional methods for detecting pollution

1. Counting plant, animal, and microbial species

2. Measuring oxygen or methane levels in water

3. Analyzing the numbers of individuals in species.

What are biosensors?

Devices that combine biological and electronic components (often built onto a microchip) to detect specific substances or conditions in the environment.

What is a microbial fuel cell?

A bioelectrochemical system that converts chemical energy in organic matter to electrical energy through the metabolic activity of microorganisms.

What are electroactive (EA) biofilms?

Biofilms produced by microorganisms that are capable of transferring electrons outside the cell, playing a key role in bioelectrochemical systems.

What are the two main mechanisms of electron transfer in MFCs?

Direct electron transfer (DET) and indirect electron transfer using mediators or shuttles.

What are the five stages of biofilm development?

1. Initial attachment

2. Irreversible attachment

3. Maturation I

4. Maturation II

5. Dispersion

What is quorum sensing?

A system of cell-to-cell communication in bacteria where they release and detect signaling molecules called autoinducers to coordinate their collective behavior.

What is the role of extracellular polysaccharides (EPS) in biofilms?

EPS forms a protective matrix around biofilm bacteria, provides structure, helps with surface attachment, and can contribute to electron transfer in some systems.

What is a membrane biofilm reactor (MBfR)?

A treatment technology based on gas-transferring membranes where biofilms form on the membrane surface and receive gaseous substrates through the membrane.

What is a membrane-aerated biofilm reactor (MABR)?

A type of MBfR where the membrane provides oxygen to the biofilm, significantly reducing energy costs compared to conventional aeration.

Why is MBfR considered "counter diffusional"?

Because the gaseous substrate (e.g., oxygen) diffuses through the membrane to the biofilm, while the complementary substrate diffuses from the bulk liquid into the biofilm.

How has genetic engineering been applied to reduce phosphate pollution?

By adding the enzyme phytase to animal feed, allowing pigs and chickens to utilize phosphate from phytate in their feed, reducing phosphate excretion by more than 30%.

What is biomining?

The use of bacteria to extract metals (like gold) from ore, saving energy and generating less waste compared to traditional smelting.

What advantage does biotechnological production of indigo have over chemical production?

Chemical production takes eight steps and uses toxic chemicals, while biotechnological production using genetically modified bacteria takes only three steps, proceeds in water, and uses simple raw materials.

What do EU Directives on genetically modified organisms require?

Detailed experimental protocols, assessment of potential risks, approval by competent authorities, and public disclosure of release information.

Why is regulation of novel organisms important in environmental biotechnology?

To ensure safe application and maintain public confidence in the technology.

What are c-type cytochromes?

Multi-heme proteins found in metal-reducing microorganisms that play a role in electron transfer to external electron acceptors.

What makes living cells capable of electrical activity despite their generally non-conductive nature?

Membrane-bound electron transport proteins and outer membrane redox proteins that can transfer electrons from inside to outside the cell.