Environmental Biotechnology Explained | Bioremediation, Bioaugmentation, Biosensors

Introduction to Environmental Biotechnology
Environmental Biotechnology and Sustainable Development
Objectives of Environmental Biotechnology
Applications of Environmental Biotechnology

1. Bioremediation
2. Monitoring through biosensors
3. Sustainable industrial processes through the use of enzymes
4. Biofuels
5. Bioplastics
6. Biopesticides

Introduction to Environmental Biotechnology

Environmental biotechnology is the application of living organisms for the protection, improvement, and restoration of environmental quality.
In other words, it is the use of biotechnology to solve environmental problems.
The International Society for Environmental Biotechnology defines environmental biotechnology as the development, use, and regulation of biological systems for:

Remediation of contaminated environments, including land, air, and water
Environment-friendly processes, such as green manufacturing technologies and sustainable development

The environment is continuously threatened by human activities carried out every day.
With the increasing global population, there is a rising use of:

Chemicals
Energy
Non-renewable resources
which leads to a growth in environmental problems.

Although efforts to prevent waste accumulation and promote recycling are increasing, environmental damage is still rising due to:

Over-consumption of resources
Large amounts of waste generation
Unsustainable use of land

A partial remedy to these environmental issues can be achieved through environmental biotechnology techniques.
These techniques involve the use of living organisms in:

Hazardous waste treatment
Pollution control

Environmental Biotechnology and Sustainable Development

Environmental biotechnology can make a major and meaningful contribution to sustainable development.
It can be applied in various ways to:

Detect pollutants in the environment
Prevent the release (emission) of pollutants
Remediate (clean up) pollutants already present in the environment

Different types of wastes, including:

Solid wastes
Liquid wastes
Gaseous wastes

can be modified through environmental biotechnology by:

Recycling them to produce new useful products, or
Purifying them so that the final by-products are less harmful to the environment

The replacement of chemical materials and industrial processes with biological technologies can help to reduce environmental damage.

Objectives of Environmental Biotechnology

The main aim of environmental biotechnology is to prevent, control (arrest), and reverse environmental degradation through the proper use of biotechnology, often in combination with other technologies.
One objective is to adopt production processes that make the best possible use of natural resources by:

Recycling biomass
Recovering energy
Minimizing the generation of waste

Another objective is to encourage the use of biotechnological techniques, especially in areas such as:

Bioremediation of contaminated land and water
Waste treatment
Soil conservation
Reforestation
Afforestation
Land rehabilitation

A further objective is to apply biotechnological processes and their products to protect the integrity of the environment, with the goal of ensuring long-term ecological security.

Applications of Environmental Biotechnology

Environmental biotechnology includes a broad range of applications such as

1. Bioremediation

2. Monitoring through biosensors

3. Sustainable industrial processes through the use of enzymes

4. Biofuels

5. Bioplastics

6. Biopesticides

1. Bioremediation

Bioremediation is the use of living organisms to remove or detoxify pollutants that contaminate soil, water, or air and pose a threat to human health.
It is also known by other terms such as biotreatment, bioreclamation, and biorestoration.
Bioremediation is not a new technique; microorganisms have long been used to remove organic matter and toxic chemicals from domestic sewage and industrial waste discharge.
It has great potential for cleaning water and soil contaminated with hazardous pollutants, domestic wastes, and radioactive wastes.
Most bioremediation processes use naturally occurring microorganisms to detect, filter, and remove toxic waste before it enters the environment or to clean up existing pollution.
Genetically modified microorganisms are also used to degrade materials that are difficult to break down naturally.
Bioremediation can be carried out in situ (at the contaminated site) or ex situ (in specialized reactors after removal of contaminated material).
Successful microbial bioremediation requires a suitable environment, and conditions such as nutrients, terminal electron acceptors (O₂/NO₂), temperature, and moisture may need to be adjusted to support microbial growth and activity.
Plants are also used in some cases; for example, sunflowers can remove cesium and strontium from contaminated areas.
Bioremediation is applied in environmental maintenance through

1. wastewater and industrial effluent treatment,

2. soil and land treatment,

3. air and waste gas management

1. Treatment of Waste Water

Wastewater treatment from septic tanks, industrial discharge, and runoff from dairy and poultry farms is one of the most common applications of environmental biotechnology.
One method involves adding microorganisms along with nutrients that allow them to survive and multiply even in harsh wastewater environments.
These microbes break down hazardous wastes, making them harmless.
Treated water usually has less odor compared to untreated wastewater.
Microorganisms can also be used to control algal growth in drinking water reservoirs, irrigation canals, hydroelectric plants, and ponds.
Introduced microbes compete with algae for nutrients and produce enzymes that break down algal cell walls.
As dead debris floats to the surface, microbes digest it, leading to clearer water.
Similar bioremediation methods are used to manage oil spills, whether from shipwrecks or fuel leaks, using comparable biological approaches.

2. Soil and Land Treatment

The heavy use of fertilizers, agricultural chemicals, and waste disposal practices has increased concerns about soil pollution.
Various fungi are used in soil bioremediation; Rhodotorula sp. converts benzaldehyde to benzyl alcohol, Candida sp. degrades formaldehyde, and Aspergillus niger breaks down tannins from tannery effluents, improving soil for plant growth.
Soil bioremediation is considered safe, reliable, cost-effective, and environmentally friendly for degrading pollutants.
It can be performed in situ or by removing soil for ex situ treatment.
In situ methods include adding nutrients, microorganisms, and ventilation at the contaminated site.
Ex situ methods include excavating soil and treating it as compost or in slurry bioreactors.
Bioremediation of soil is often less expensive than physical methods, and the by-products are usually harmless.
During treatment, soil microbes convert organic pollutants into carbon dioxide, water, and biomass under both aerobic and anaerobic conditions.
Soil treatment can also be done using bioreactors, and the microbes used may be natural or genetically engineered.

3. Air and Waste Gases Treatment

Air pollution mainly results from human activities, especially the burning of fossil fuels in industries and vehicles.
Incomplete fuel combustion releases volatile organic compounds (VOCs) into the air.
Landfills and waste disposal sites emit methane, and many household products also release VOCs.
Initially, biological air treatment seemed impossible, but advancements in biological waste gas purification technologies made it feasible.
Technologies such as biofilters and membrane bioreactors are now used to treat polluted air.
Contaminated air is passed through bioreactors where volatile compounds move from the gas phase to the liquid phase.
A microbial community of bacteria, fungi, and protozoa grows in the liquid phase and removes pollutants.
Bacteria commonly used for this purpose include Nocardia sp. and Xanthomonas sp.

2. Environmental Monitoring by Biosensors

A wide variety of biological methods are used to detect pollution and for the continuous monitoring of pollutants in the environment.
Biotechnology provides advanced techniques for diagnosing environmental problems and assessing normal environmental conditions, helping people become better informed about their surroundings.
These methods are generally cheaper, faster, and portable compared to conventional laboratory analysis.
Instead of collecting soil or water samples and sending them to a lab, scientists can measure contamination directly at the site and obtain immediate results.
Biological detection methods using biosensors and immunoassays have been developed and are now commercially available.
A biosensor may use a biological entity such as bacteria to monitor chemical levels, or it may use chemicals to detect biological entities such as pathogens.
Immunoassays use labelled antibodies and enzymes to measure pollutant concentrations.
When a pollutant is present, the antibody binds to it, and this interaction can be detected through color change, fluorescence, or radioactivity.

Biosensors

A biosensor is an analytical device that converts a biological response into a measurable physical, chemical, or electrical signal.
Most biosensors combine biological components with electronic systems and are often constructed on microchips.
The biological element may be an enzyme, antibody, colony of bacteria, membrane, neural receptor, or even a whole organism.
These biological components are immobilized on a substrate, and their properties change in response to environmental effects in ways that can be detected electronically or optically.
Biosensors allow quantitative measurement of pollutants with very high precision and sensitivity.
Current applications of biosensors include detecting toxin levels in ecosystems, identifying airborne pathogens such as anthrax, and monitoring blood glucose levels.
Biosensors have been developed for detecting carbohydrates, organic acids, aromatic hydrocarbons, pesticides, and pathogenic bacteria.
Saccharomyces cerevisiae (yeast) is used to detect cyanide in river water, while Selenastrum capricornatum (a green alga) is used for heavy metal detection.
Many herbicides in river water can be detected using algal-based biosensors, where stress on the organisms is measured through changes in the optical properties of chlorophyll.

3. More Sustainable Industrial Processes through the Use of Enzymes

The leather industry uses enzymes instead of harsh chemicals traditionally employed in hide cleaning.
In the textile industry, enzymes have replaced chemicals used for bleaching.
The pulp and paper industry is reducing chlorine use through the application of enzymes.
Washing powders contain grease- and protein-digesting enzymes, which significantly reduce the amount of detergent required.
Enzymes help lower the environmental impact of detergents because they save energy by enabling washing at lower temperatures, replace undesirable chemical compounds, do not interfere with sewage treatment processes, pose no risk to aquatic life, and are biodegradable.