Ideonella sakaiensis
Ideonella sakaiensis | |
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Scientific classification | |
Domain: | Bacteria |
Phylum: | Pseudomonadota |
Class: | Betaproteobacteria |
Order: | Burkholderiales |
Family: | Comamonadaceae |
Genus: | Ideonella |
Species: | I. sakaiensis
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Binomial name | |
Ideonella sakaiensis Yoshida et al. 2016[1]
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Ideonella sakaiensis is a
Discovery
Ideonella sakaiensis was first identified in 2016 by a team of researchers led by Kohei Oda of Kyoto Institute of Technology and Kenji Miyamoto of Keio University after collecting a sample of PET-contaminated sediment at a plastic bottle recycling facility in Sakai, Japan.[2][3] The bacteria was first isolated from a consortium of microorganisms in the sediment sample, which included protozoa and yeast-like cells. The entire microbial community was shown to mineralize 75% of the degraded PET into carbon dioxide once it had been initially degraded and assimilated by Ideonella sakaiensis.[2]
Characterization
Physical attributes
Ideonella sakaiensis is
Chemical attributes
I. sakaiensis also tests positive for oxidase and catalase. The bacterium grows at a pH range of 5.5 to 9.0 (optimally at 7 to 7.5) and a temperature of 15–42 °C (59–108 °F) (optimally at 30–37 °C (86–99 °F)).
Use of characteristics
The gram negativity in bacteria makes it so they have resistant abilities and genes; this could include antibiotic resistance. The gram negativity as a characteristic also signifies this bacteria has a thin cell wall and has a high lipid content.[citation needed]
The aerobic aspect of this bacteria makes it so that it can only grow and thrive in an environment that contains the presence of oxygen within their vicinity. Ideonella sakaiensis and other aerobic bacterium are therefore known to survive in oxygen-rich soil that is moist and aerated.[citation needed]
The flagellum attached to this bacteria are used as motile organelles and are able to rotate and thrust the cell throughout its environment by creating motion. The bacterium was also shown to grow on Polyethylene terephthalate (PET) surface which is a type of plastic. The bacteria was able to adhere to the PET plastic with its thin flagellum. This is shown in the image to the right. These flagellum may also function to secrete PET-degrading enzymes onto the PET surface known as PETase.[citation needed]
Through phylogenetic analysis, the species was shown to be a part of the genus Ideonella, but possessed a significantly different genome than other known species in the genus, including Ideonella dechloratans and Ideonella azotifigens, thus justifying its classification as a new species.[4]
Degradation and assimilation of PET
Ideonella sakaiensis adhere to PET surface and use a secreted PET
Impact and applications
The discovery of Ideonella sakaiensis has potential importance for the degradation of PET plastics. Prior to its discovery, the only known degraders of PET were a small number of bacteria and fungi, including Fusarium solani, and no organisms were definitively known to degrade PET as a primary carbon and energy source.[2] The discovery of I. sakaiensis spurred discussion about PET biodegradation as a method of recycling and bioremediation.[2]
The wild-type bacterium is able to colonize and break down a thin (0.2 mm thickness) film of low-crystallinity (soft) PET in approximately 6 weeks, and the responsible PETase enzyme was shown to degrade high-crystallinity (hard) PET approximately 30-fold slower (180 weeks or more than 3 years) than low-crystallinity PET.[2] A large amount of manufactured PET is highly crystalline (e.g. plastic bottles), so it is thought that any prospective applications of the I. sakaiensis PETase enzyme in recycling programs will need to be preceded by genetic optimization of the enzyme.[2][7] The MHETase enzyme could also be optimized and used in recycling or bioremediation applications in combination with the PETase enzyme. It degrades the MHET produced by the PETase into ethylene glycol and terephthalic acid.[2] Once formed, these two compounds can be further biodegraded into carbon dioxide by I. sakaiensis or other microbes, or they can be purified and used to manufacture new PET in an industrial recycling plant setting.[2][8]
Ideonella sakaiensis is being studied for its PET degrading capabilities as a means of water management issues of sewage fed fisheries. Various strains of this bacterium has been shown to not pose any threats to the growth and cultivation of fish. This species of bacteria are able to properly use PET as a source of carbon and thrive in wastewater and plastic polluted water ecosystems, showing its promise as a cost-effective anti-pollutant.[9]
Genetic engineering
The PET plastic degrading enzyme of Ideonella sakaiensis known as;
Coagulation Filtration System
In 2021, fifth graders Julia Stewart and Jacob Park created the concept of a Coagulation Filtration System for Toshiba's ExploraVision contest, which utilizes Ideonella sakaiensis in a process that filters, coagulates, flocculates, and sediments water in a more environmentally friendly and efficient way.[13][14][15] This project won the 4-6 division of ExploraVision nationally.[13][14]
See also
- PET bottle recycling
- PETase, the enzyme produced by this bacterium.
- Pestalotiopsis microspora, an endophytic fungus species capable of breaking down polyurethane.
References
- S2CID 31146235.
- ^ S2CID 31146235.
- "Discovery of a Bacterium that Degrades and Assimilates Poly(ethylene terephthalate) could Serve as a Degradation and/or Fermentation Platform for Biological Recycling of PET Waste Products" (PDF). Kyoto Institute of Technology (Press release). 30 March 2016.
- .
- ^ S2CID 31146235.
- S2CID 231865499.
- ISSN 1350-0872.
- ^ Coghlan A. "Bacteria found to eat PET plastics could help do the recycling". New Scientist. Retrieved 18 March 2016.
- .
- ^ Misra J (April 2020). "Managing Wastewater Using Plastic Eating Bacteria - A Sustainable Solution for Sewage Fed Fisheries". Journal of the Indian Chemical Society. 97 (4): 513–519.
- ^ Carrington D (28 September 2020). "New super-enzyme eats plastic bottles six times faster". The Guardian. Retrieved 12 October 2020.
- ^ "Plastic-eating enzyme 'cocktail' heralds new hope for plastic waste". phys.org. Retrieved 12 October 2020.
- PMID 32989159.
- ^ a b "Eight Student Teams Named National Winners of 29th Annual ExploraVision Challenge". news.toshiba.com. Retrieved 3 December 2021.
- ^ a b "Loading site please wait..." www.exploravision.org. 18 May 2021. Retrieved 3 December 2021.
- ^ "Home | Coagulation Filtration System". ExploraVision.PPT te. Retrieved 3 December 2021.