Course: SAT 170 Introductory Biotechnology

Unit 9 Reading and Multimedia Assignment

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- Unit 9
- Table of Contents (Selected)
- Unit 9 Key Terms (Selected)

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“Microorganisms and environmental cleanup," by Boundless, CC BY SA 3.0

https://www.boundless.com/biology/biotechnology/biotechnology-and-everyday-life/microrganisms-and-environmental-cleanup/

Reading Assignment: Bioremediation
Bioremediation is the use of living organisms, primarily microorganisms, to degrade environmental contaminants into less toxic forms.

Biological Wastewater Treatment

- Microorganisms have the ability to break down chemicals and can be used in environmental clean up. But if it is not possible (or safe) to directly use the microorganism, genes from those organisms can be transferred to other microorganisms, which are suitable for environmental remediation.
- Many microbes have been genetically engineered and may be used to mine minerals or to clean up toxic mine wastes.
- Research is also underway to develop microorganisms that can break down chlorinated hydrocarbons to treat wastewater.

Bioremediation is an alternative that offers the possibility to destroy toxic pollutant using natural biological activity. By definition, bioremediation is the use of living organisms, primarily microorganisms, to degrade the environmental contaminants into less toxic forms. It uses naturally occurring bacteria and fungi or plants to degrade or detoxify substances hazardous to human health and/or the environment. The microorganisms may be indigenous to a contaminated area or they may be isolated from elsewhere and brought to the contaminated site. Contaminant compounds are transformed by living organisms through reactions that take place as a part of their metabolic processes. Biodegradation of a compound is often a result of the actions of multiple organisms. When microorganisms are imported to a contaminated site to enhance degradation we have a process known as bioaugmentation. Bioremediation techniques are typically more economical than thermal and physico-chemical remediation such as incineration.

Not all contaminants, however, are easily treated by bioremediation using microorganisms. For example, heavy metals such as cadmium and lead are not readily absorbed or captured by organisms. The assimilation of metals such as mercury into the food chain may worsen matters. Phytoremediation is useful in these circumstances because natural plants or transgenic plants are able to bioaccumulate these toxins in their above-ground parts, which are then harvested for removal. The heavy metals in the harvested biomass may be further concentrated by incineration or even recycled for industrial use.

The use of genetic engineering to create organisms specifically designed for bioremediation has great potential. The bacterium Deinococcus radiodurans (the most radioresistant organism known) has been modified to consume and digest toluene and ionic mercury from highly radioactive nuclear waste. In addition, when it is not desirable to directly use a microorganism capable of breaking down a specific chemical, genes from these organisms can be transferred to other microorganisms that are more suitable for environmental remediation. However, ecological and environmental concerns and regulatory constraints are major obstacles for testing GEM in the field. These problems must be solved before GEM can provide an effective clean-up process at lower cost.

Cleaning up of petroleum hydrocarbons in the subsurface environment is a real world problem. A better understanding of the mechanism of biodegradation has a high ecological significance that depends on the indigenous microorganisms to transform or mineralize the organic contaminants. Microbial degradation process aids the elimination of spilled oil from the environment after critical removal of large amounts of the oil by various physical and chemical methods. This is possible because microorganisms have enzyme systems to degrade and utilize different hydrocarbons as a source of carbon and energy.