sakaiensis

Ideonella sakaiensis is a Gram-negative, rod-shaped bacterium isolated from a PET-contaminated site in Sakai, Osaka Prefecture, Japan, in 2016. It belongs to the genus Ideonella and was named after the city of isolation. The organism can utilize polyethylene terephthalate (PET) as a carbon and energy source under aerobic conditions, albeit slowly.

The strain produces two extracellular enzymes, PETase and MHETase, which cooperate to hydrolyze PET into smaller compounds. PETase catalyzes the hydrolysis of PET to mono(2-hydroxyethyl) terephthalic acid (MHET) and terephthalic acid, and MHETase further hydrolyzes MHET to terephthalic acid and ethylene glycol. This enzymatic system has become a model for plastic-degrading enzymes and has inspired protein engineering to enhance activity and stability for potential applications in biorecycling.

Physiology: Ideonella sakaiensis is a Gram-negative, non-motile, rod-shaped bacterium. It grows at moderate temperatures and neutral pH in enriched laboratory media. Its natural habitat is PET-rich environments, where it may contribute to plastic degradation, although its rate of degradation is slow under natural conditions.

Genome and significance: The genome has been sequenced, revealing genes encoding PET-degrading enzymes and pathways for metabolizing plastic-derived products. The discovery of Ideonella sakaiensis and the PETase/MHETase system has spurred ongoing research into engineering more efficient enzymes and integrated biotechnological approaches to improve PET recycling.