Question

The bacteria used for scavenging oil spills by digesting hydrocarbons of crude oil is
(A) Rhizobium meliloti
(B) Bacillus thuringiensis
(C) Pseudomonas putida
(D) Escherichia coli

Answer 1

Hint: The spilling or leakage of oil into sea or ocean water during its transportation from one place to another is called oil spill. Oil is a viscous liquid containing a mixture of hydrocarbons. Leakage of oil in sea or ocean water causes marine pollution.

Complete answer:
Oil is an important natural resource. It is a non-renewable resource that has limited production. Only few countries in the world produce oil which they export to non-oil producing countries. Oil is mainly transported to non-oil producing countries by ships via sea route. Many times some leakage can occur in the storage tank of a ship that can cause oil to spill into sea/ocean water. This leakage can occur as a result of accident or human error.
Oil spill is one of the main causes of marine pollution. Small oil spills occur every now and then, but it is the large oil spills that are damaging to marine life. The leaked oil can either disperse in water or can form a thick layer on the surface of water. If the oil forms a layer on the water surface, then it can even reach coastal areas along with water currents. The oil that reaches the coastal areas can harm coastal organisms like mammals, birds and invertebrates. Dispersed oil can affect organisms like fishes and zooplanktons. These organisms can ingest oil which can result in abnormalities in development and reproduction and can even cause mortality.
There are many bacteria that can clean or remove the oil from ocean water by degrading hydrocarbons. These bacteria are known as hydrocarbon degrading bacteria. Pseudomonas can digest the hydrocarbons in oil. They are gram negative bacteria that are found in soil, water and plants and animals. A species called Pseudomonas putida is widely used in oil spill decontamination or bioremediation. It is known to break down many aromatic compounds like hydrocarbons.
Rhizobium meliloti is a soil bacterium that fixes the atmospheric nitrogen.
Bacillus thuringiensis is a soil bacterium that is used in biological control of pests.
Escherichia coli is a bacterium that lives in the human intestine. It is generally harmless, but some of its strains can cause diseases.

So the correct answer is Option (C) Pseudomonas putida.

Note:
In the above we detailed the evolution of organisms and geology in different eras according to geological time scale. It showed us the history of developed organisms and geology. Evolution is important for survival because only the fittest can survive to the last and weak one gets eliminated. Pseudomonas putida is a genetically engineered bacterium produced by Dr. Ananda Mohan Chakraborty in 1971. There are four naturally occurring species of Pseudomonas that are known to degrade the oil. Dr. Chakraborty genetically modified these species and produced a more stable species of Pseudomonas known as Pseudomonas putida. Pseudomonas putida can digest about 2/3 of hydrocarbons present in oil and at a much faster rate than the four natural species. For this reason, it is also known as the oil eating bacteria.