The World’s Toughest and Extremely Radiation Resistant Bacterium: Deinococcus radiodurans

In The Guinness Book of World Records Deinococcus radiodurans listed as world’s toughest bacterium.This bacterium is resistant to extreme radiation which is higher than our tolerable limit.
Radiation equal to 5 Gy can kill a human and if we increase the level of radiation up to 200 to 800 Gy then it will destroy E. coli bacteria and further increase in radiation over 4,000 Gy will kill tardigrade (also known as water bear)that has capability to survive in space vacuum.But Deinococcus radiodurans can tolerate radiation dose of 5,000 Gy.

Extremely Radiation Resistant Bacterium
Deinococcus radiodurans has capability of repairing DNA that makes this bacterium so tough. When bacteria expose in high level of radiation then radiation shatter the D. radiodurans genome but the bacteria stitches the fragments back together within a few hours as new.
Deinococcus radiodurans natural habitat are not actually known by scientist. These bacteria found in elephant dung and granite of Antarctic dry valleys where environment most closely resemble like Mars.
This bacterium can survive in cold , dehydration, vacuum, and even in acid. Bacteria name obtain from ancient Greek language that mean terrible berry that resist radiation.
These bacteria not cause any illness or major disease and having size 1.5 to 3.5 µm forming a tetrad with four cell stick together. The bacteria can easily cultured and its colonies are smooth, convex, and pink to red in color.
Bacteria quality to survive in high radiation make it functional for waste management in nuclear weapons manufacture plant where radioactive waste generated. Deinococcus has been genetically engineered by taking mercuric reductase quality from Escherichia coli bacteria to detoxify the ionic mercury residue frequently found in radioactive waste of plant.
Scientist finding the way to use these bacteria in space flight where it can use in sewage treatment and by environmental engineering they can make the Martian surface more suitable for human colonization.