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Bioremediation

Our world is poisoned with pollution that has manifested itself in every form possible. Every inch of our planet has been engulfed and the situation worsens as we converse. With Delhi’s air quality index beyond the scope of the air quality meter and the waters of its rivers turned ink black, landfills competing tall and proud monuments and mountain ranges, single-use plastics spread everywhere.

Microbes are microorganisms that also thrive in almost every habitat possible. They can be found in the most extreme habitats one could ever think of, from deserts and snow-capped mountains to high radiation environments. So do they make their way through the contaminants that traverse our Earth? Yes, microbes do thrive in certain contaminants.

Bioremediation is a process that utilizes naturally occurring bacteria or foreign bacteria that have special characteristics to decompose the unwanted chemicals. So these naturally occurring microbes utilize the contaminant as their source of growth. You could stimulate this growth by introducing nutrients for it to grow and spread. This is known as bio-stimulation. This can be done by addition of various forms of rate limiting nutrients and electron acceptors, such as phosphorus, nitrogen, oxygen, or carbon (e.g. in the form of molasses). Or you could introduce a foreign bacteria that can degrade the contaminant you want. This process is called bio-augmentation. Though the benefits are countless, it should be dealt with skepticism. What if biostimulation and bioaugmentation alter the microbial assembly of a place and potentially extinguish certain microbes that are important for that particular environment.

Precision bioremediation involves identifying the most suitable bacteria for a particular situation by analysing microbial pool by amplicon sequencing methods and transferring plasmids (through conjugation and other methods) from one microbe to another microbe that is less competitive. Therefore it’ll only last for a short time and do its job, and that gene disappears from the microbial assembly and thereby does not alter the microbial makeup of a particular area.

Bioremediation is mostly being used to clean up oil spills. Alkanivorax borkumensis (I)is a marine pathogenic bacteria which possesses a group of enzymes called hydroxylases which grows rapidly and degrades benzene and toluene.

Bioremediation has its own disadvantages. One of the major concern is that a more toxic product than the parental unit may be formed after degradation. For example, tetrachloroethylene may be converted into vinyl chloride which is a carcinogen. Therefore this solution should be approached with extreme caution and after appropriate research. 

Sachin Babu