Bioremediation

Daily life activities going on the earth produce a lot of garbage and trash which is a potential threat for our environment. Due to the industrial boom and modern lifestyle, there is many folds increase in environmental pollution. It is not only risky for human beings, but also produces severe side effects on other life forms. The removal of this trash and cleaning of environment is one of the biggest challenges of this era, biotechnology offers a better option in this regard i.e., Bioremediation. It is a process of cleaning the contaminated environment by making use ofliving organisms.
The conventional method of removing the contamination is to move it or dump it into landfills. But with the passage of time and increasing population it has become very difficult and expensive method. Bioremediation is biological recycling of wastes into other useable forms and thus it eradicates the contamination. Microorganisms are found nearly everywhere on the earth and have so much versatility in metabolism and they can be propagated easily even in harsh environmental conditions, and these properties make them viable to be used for remediation. Bacteria, fungi and archaea are mainly used as bioremediators and are effective in soil, sediments, water surfaces and underground water resources as well, where they utilize the contamination and dirt as a source of food and energy. Bioremediation may be:

• Microbial Bioremediation: when microorganisms are used such as bacteria
• Phytoremediation: when plants are used
• Mycoremediation: when fungi are used 

Since bioremediation involves enzymatically mediated reactions that is why optimum temperature and other environmental conditions are required. For growth of microbes’ proper nutrients are also required so that they can grow and perform their function rapidly. To improve the process of bioremediation some ‘amendments’ are often added. These amendments may vary according to the type of contamination and microorganisms used in the process. Sometimes when indigenous microbes are not present the grown cultures are also added, especially when some specific specie is required to clean some specific type of pollution.
Factors Affecting Bioremediation
There are many factors which affect the process of bioremediation. Some of which are: 

•  Temperature
•  pH
•  Availability of nutrients
•  Oxygen concentration
•  Moisture content
•  Presence of heavy metals
•  Degree of toxicity of contamination

Different Approaches of Bioremediation
1. In-situ Bioremediation
It is the more common and widely applied method. In-situ refers to the in-place treatment usually used for contaminated soil and underground water. In this method nutrients and oxygen are circulated in the form of aqueous solutions mostly by digging underground cavities. Mostly it is used to treat the underground water.
2. Ex-situ Bioremediation
Ex-situ refers to ‘above the ground’ treatment. In this method, usually the contaminated soil is first excavated from its native place and then it is subjected to the treatment such that it may be heated and/or mixed with different amendments to complete the procedure. It may also be carried out in special tanks or pads to prevent the vapors from contaminating further.

Why Bioremediation??
1. Cost-effective
2. Environment friendly as in chemical methods usually the residual chemicals used are also harmful for the environment
3. Can be used to clean a larger area simultaneously
4. It has been proved to be successful in cleaning such contamination which were almost impossible to clean such as spilled crude oil on the surface of sea by oil-eating microbes, cleaning the filth in poultry farms using different enzymes such as keratinase, removal of pesticides from farmlands by their complete degradation by microorganisms and many more.
5. Generates very little to negligible amount of waste.
6. The end-products are harmless or useful biological products.

Limitations
Apart of many advantages there are also some limitations of bioremediation. Most importantly it is a slower and long procedure and can take even years for complete cleaning the pollutants. Another point for consideration is the specificity of organisms to degrade the specific contamination therefore particular species or cultures are required for different types of pollutants. Furthermore, the process must be controlled so that it could be limited only to the specific contaminated area.

In short, bioremediation is a very useful and incredible way to clean, remediate and
decontaminate the environment. It has been applied in many cases and is proved to be fruitful.
Further research is required in this field to make it more applicable and more successful.

By: Mehwish Hamid

References:
1. Kumar, A., Bisht, B. S., Joshi, V. D., & Dhewa, T. (2011). Review on bioremediation of polluted environment: a management tool. International journal of environmental sciences, 1(6), 1079-1093.

2. Abatenh, E., Gizaw, B., Tsegaye, Z., & Wassie, M. (2017). The role of microorganisms in bioremediation-A review. Open Journal of Environmental Biology, 2(1), 030-046.

3. http://learnbioremediation.weebly.com/in-situ--ex-situ-bioremediation-treatments.html