Nylon-eating bacteria

Nylon-eating bacteria are a strain of Flavobacterium that is capable of digesting certain byproducts of nylon 6 manufacture. This strain of Flavobacterium, Sp. K172, became popularly known as nylon-eating bacteria, and the enzymes used to digest the man made molecules became collectively known as nylonase.

Discovery

In 1975 a team of Japanese scientists discovered a strain of Flavobacterium living in ponds containing waste water from a factory producing nylon that was capable of digesting certain byproducts of nylon 6 manufacture, such as the linear dimer of 6-aminohexanoate, even though those substances are not known to have existed before the invention of nylon in 1935. Further study revealed that the three enzymes the bacteria were using to digest the byproducts were significantly different from any other enzymes produced by other Flavobacterium strains (or any other bacteria for that matter), and not effective on any material other than the manmade nylon byproducts.

Later research

This discovery led geneticist Susuma Ohno to speculate that the gene for one of the enzymes, 6-aminohexanoic acid hydrolase, had come about from the combination of a gene duplication event with a frame shift mutation. Ohno suggested that many unique new genes have evolved this way.

A series of recent studies by a team led by Seiji Negoro of the University of Hyogo, Japan, suggest that in fact no frameshift mutation was involved in the evolution of the 6-aminohexanoic acid hydrolase.[1] However, many other genes have been discovered which did evolve by gene duplication followed by a frameshift mutation affecting at least part of the gene. A 2006 study found 470 examples in humans alone.[2]

Scientists have also been able to induce another species of bacteria, Pseudomonas aeruginosa, to evolve the capability to break down the same nylon byproducts in a laboratory by forcing them to live in an environment with no other source of nutrients. The P. aeruginosa strain did not seem to use the same enzymes that had been utilized by the original Flavobacterium strain. Other scientists were able to get the ability to generate the enzymes to transfer from the Flavobacterium strain to a strain of E. coli bacteria via a plasmid transfer.

As stated by jimbofromfrag

Role in creation-evolution controversy

Main article: Nylon-eating bacteria and creationism

There is scientific consensus that the capacity to synthesize nylonase most probably developed as a single-step mutation that survived because it improved the fitness of the bacteria possessing the mutation. This is seen as good example of evolution through mutation and natural selection. As a result nylon-eating bacteria have been discussed, in articles and on websites, in the context of the creation-evolution controversy.

See also

• E. coli long-term evolution experiment
• Radiotrophic fungus
• Evolution
• Creation-evolution controversy

References

• Kinoshita, S., Kageyama, S., Iba, K., Yamada, Y. and Okada, H., Utilization of a cyclic dimer and linear oligomers of ε-aminocapronoic acid by Achromobacter guttatus K172, Agric. Biol. Chem. 116, 547-551 (1981), FEBS 1981
• Yomo, T., Urabe, I. and Okada, H., No stop codons in the antisense strands of the genes for nylon oligomer degradation, Proceedings of the National Academy of Sciences USA 89:3780–3784, 1992
• IRFAN D. PRIJAMBADA, SEIJI NEGORO, TETSUYA YOMO, AND ITARU URABE, Emergence of Nylon Oligomer Degradation Enzymes in Pseudomonas aeruginosa PAO through Experimental Evolution PDF, APPLIED AND ENVIRONMENTAL MICROBIOLOGY, May 1995
• Susumu Ohno, Birth of a unique enzyme from an alternative reading frame of the preexisted, internally repetitious coding sequence, Proc. Natl. Acad. Sci. USA Vol. 81, pp. 2421-2425, April 1984
• Negoro S, Taniguchi T, Kanaoka M, Kimura H, Okada H. Plasmid-determined enzymatic degradation of nylon oligomers. Journal of Bacteriology. July 1983