Pseudideonella sakaiensis
| Pseudideonella sakaiensis | |
|---|---|
Scientific classification  | |
| Domain: | Bacteria |
| Kingdom: | Pseudomonadati |
| Phylum: | Pseudomonadota |
| Class: | Betaproteobacteria |
| Order: | Burkholderiales |
| Family: | Sphaerotilaceae |
| Genus: | Pseudideonella |
| Species: | P. sakaiensis |
| Binomial name | |
| Pseudideonella sakaiensis (Tanasupawat et al. 2016) Lu & Chen 2026[1] | |
| Synonyms[1] | |
| |
Pseudideonella sakaiensis is an aerobic, Gram-negative bacterium in the family Sphaerotilaceae. Formerly known as Ideonella sakaiensis, it is notable for its ability to degrade and assimilate low-crystallinity polyethylene terephthalate (PET), using PET-derived compounds as carbon and energy sources.[2] The type strain, 201-F6, was isolated from a microbial consortium collected at a PET-bottle recycling site in Sakai, Japan.[3]
Taxonomy
The species was originally classified as Ideonella sakaiensis on the basis of its phenotypic characteristics, 16S rRNA gene sequence, and DNA–DNA relatedness to other members of Ideonella.[3] A genome-based taxonomic revision subsequently transferred it to Piscinibacter as Piscinibacter sakaiensis.[4]
Further 16S rRNA and phylogenomic analyses showed that the species occupied a distinct position from both Ideonella and Piscinibacter. It was consequently transferred to the monotypic genus Pseudideonella as Pseudideonella sakaiensis.[5]
Characteristics
Cells of P. sakaiensis are aerobic, non-spore-forming rods measuring approximately 0.6–0.8 μm in width and 1.2–1.5 μm in length. They are motile by means of a polar flagellum. The organism is catalase-positive and oxidase-positive.[3]
The type strain grows at temperatures between 15 and 42 °C, with optimum growth at 30–37 °C. Growth occurs between pH 5.5 and 9.0, with an optimum between pH 7.0 and 7.5.[3]
PET degradation and assimilation
P. sakaiensis produces two enzymes that act sequentially during PET degradation. A secreted PET hydrolase, commonly called PETase, hydrolyzes ester bonds in PET and produces soluble compounds, principally mono(2-hydroxyethyl) terephthalate (MHET), together with smaller amounts of bis(2-hydroxyethyl) terephthalate (BHET) and terephthalic acid (TPA).[2] A second enzyme, MHET hydrolase or MHETase, hydrolyzes MHET into TPA and ethylene glycol. The resulting monomers can be transported into the cell and metabolized.[2]
Under laboratory conditions, the wild-type bacterium degraded a thin film of low-crystallinity PET over approximately six weeks at 30 °C.[2] Its activity is strongly affected by the physical properties of the polymer. Amorphous PET films and amorphous portions of consumer containers can support bacterial growth, whereas highly crystalline PET from the main body of plastic water bottles does not support comparable growth or degradation.[6]
Enzyme engineering
PETase and MHETase have been investigated as components of enzymatic PET-recycling systems. Combining the two enzymes increased PET depolymerization by preventing the accumulation of MHET. Engineered fusion proteins containing PETase and MHETase also displayed greater activity than the separate wild-type enzymes under experimental conditions.[7]
An engineered variant derived from the PETase of P. sakaiensis, called FAST-PETase, was developed using structure-based machine learning. It showed increased activity and stability between 30 and 50 °C and depolymerized a range of post-consumer, predominantly amorphous PET products under laboratory conditions. Thermal pretreatment was still required for complete degradation of an entire PET water bottle.[8]
See also
References
- 1 2 "Species: Pseudideonella sakaiensis". List of Prokaryotic names with Standing in Nomenclature. Leibniz Institute DSMZ. Retrieved 13 August 2026.
- 1 2 3 4 Yoshida S, Hiraga K, Takehana T, Taniguchi I, Yamaji H, Maeda Y, et al. (2016). "A bacterium that degrades and assimilates poly(ethylene terephthalate)". Science. 351 (6278): 1196–1199. Bibcode:2016Sci...351.1196Y. doi:10.1126/science.aad6359. PMID 26965627.
- 1 2 3 4 Tanasupawat S, Takehana T, Yoshida S, Hiraga K, Oda K (2016). "Ideonella sakaiensis sp. nov., isolated from a microbial consortium that degrades poly(ethylene terephthalate)". International Journal of Systematic and Evolutionary Microbiology. 66 (8): 2813–2818. doi:10.1099/ijsem.0.001058. PMID 27045688.
- ↑ Liu Y, Du J, Pei T, Du H, Feng GD, Zhu H (2022). "Genome-based taxonomic classification of the closest-to-Comamonadaceae group supports a new family Sphaerotilaceae fam. nov. and taxonomic revisions". Systematic and Applied Microbiology. 45 126352. doi:10.1016/j.syapm.2022.126352.
- ↑ Lu H, Chen L (2026). "Emended description of the genus Rhizobacter and reclassification of Ideonella sakaiensis as Pseudideonella sakaiensis gen. nov., comb. nov". International Journal of Systematic and Evolutionary Microbiology. 76 (6) 007181. doi:10.1099/ijsem.0.007181.
- ↑ Wallace NE, Adams MC, Chafin AC, Jones DD, Tsui CL, Gruber TD (2020). "The highly crystalline PET found in plastic water bottles does not support the growth of the PETase-producing bacterium Ideonella sakaiensis". Environmental Microbiology Reports. 12 (5): 578–582. doi:10.1111/1758-2229.12878. PMID 32783383.
- ↑ Knott BC, Erickson E, Allen MD, Gado JE, Graham R, Kearns FL, et al. (2020). "Characterization and engineering of a two-enzyme system for plastics depolymerization". Proceedings of the National Academy of Sciences of the United States of America. 117 (41): 25476–25485. Bibcode:2020PNAS..11725476K. doi:10.1073/pnas.2006753117. PMC 7568301. PMID 32989159.
- ↑ Lu H, Diaz DJ, Czarnecki NJ, Zhu C, Kim W, Shroff R, et al. (2022). "Machine learning-aided engineering of hydrolases for PET depolymerization". Nature. 604: 662–667. doi:10.1038/s41586-022-04599-z.