[BojanaL]

Elimination of xenobiotics

Unfortunately, xenobiotics are part of human life in the modern society. Different industries develop and produce various compounds that should improve human’s life, but most of them are highly toxic and consequences to the biomes around the globe are usually terrible. Xenobiotics associated with production of plastics, pesticides, paints, textile and pharmaceuticals can’t be eliminated from our lives, but we should put more effort in elimination of toxic materials before our planet turn into one big bag of waste.

Microorganisms have always been the easiest and most efficient tool used for elimination of abundant or harmful chemicals from our environment. They can be found all around the planet, they are easily grown in laboratory conditions, scientists are familiar with their affinities and characteristics, they possess needed enzymes and they enjoy “eating” chemical waste. They can be used for different types of organic waste, but some artificially created compounds are simply un-digestible: microorganisms are not metabolically “equipped” to break down chemical bonds in compounds of interest. Luckily, another scientific branch, genetic engineering, allowed scientist to modify microorganisms and turn them into organisms able to degrade xenobiotics. Genetically modified Pseudomonas species are mostly used in the process of bioremediation. Pseudomonas harboring TOL plasmid, for example, degrades toluene, m-xylene and p-xylene. Insertion of bioluminescence gene allows researchers to monitor Pseudomonas during bioremediation.

Another way to help nature get rid of all those waste materials could be achieved by combining human and microbial activity. Chemicals that can’t be degraded by microorganisms directly, can be chemically altered to their smaller or easier-to-break parts and then degraded using already known microorganisms. Combination of human and microbial activity could be a life savior in the case of accidental oil spills that have devastating consequences on the marine organisms. Large oil spill can’t be degraded solely by microorganisms due to large quantities of spilled oil and because oil contains some toxic ingredients. Newly invented chemical could solve this problem.

SOT 11 (SOT stands for solid oil treatment) is an inorganic solid absorbent that consists of nontoxic mineral granules, which are chemically inert. This chemical is developed by Oil Treatment International (OTI), a Swiss based company, over a period of 20 years. How this mineral mixture works? Since it acts as strong absorbent, once it is deposited over the spill, oil will compact in small particles that will (because of the gravity) sink to the bottom of the sea. Due to firm bond between oil and SOT 11, oil can’t leave this complex and enter the water or water surface again. Elimination of the superficial oil film allows animals to come in contact with oxygen and establish normal breathing again. Also, removal of the spill will allow sunlight to reach underwater photosynthetic organisms (without light, they can’t produce food), and prevent animals that spend their life both on the land and in the water to end up covered in oil. Birds can’t fly if their feather is glued in oil, and it has toxic effect when animal swallow it. What is happening with oil-absorbent particles once they precipitate on the bottom of the ocean? Closer examination showed that living creatures on the marine floor don't change their normal life activities during this process. Once on the bottom, shredded in small pieces, oil-SOT 11 will become food for the oil-digesting organisms such as fungi, algae, protozoa and bacteria. Digestion includes several species that are active in different stages because chemical degradation of oil happens in cascades. Low level of oxygen on the bottom is not a problem, because oil degradation can happen both under aerobic and anaerobic conditions. Whole process happens really quickly and end products are water and carbon dioxide. Since this method is still new and needs to be assessed for both safety and efficacy, regulatory body requested regular checks of the underwater processes that are happening after the SOT 11 is added. Sampling of the sand from the sea bottom showed that almost all oil-SOT 11 particles vanished (digested by the sea microorganisms) within a week. This result is amazing and when compared to absorbent non-treated area, it showed 99% more success in oil removal and its final degradation & elimination from the ecosystem.

Oil spills are dangerous and unfortunately, often ecological disasters. Although there isn’t a way to prevent them from happening, at least we can help ecosystem recuperate after oil is spilled.