This document discusses biodegradation of plastics like PET and the enzymes that enable this process. It notes that biodegradation is the breakdown of materials by microorganisms like bacteria and fungi. It then discusses the discovery of the PETase enzyme in 2016 in Ideonella sakaiensis bacteria found near a PET bottle recycling site. PETase breaks down PET plastic into MHET and other compounds. A second enzyme, MHETase, then further breaks down MHET into its monomers of terephthalate and ethylene glycol. Research is exploring using these enzymes to aid in the recycling of plastic waste.

2. BIODEGRADATION
• Biodegradation is the naturally-occurring breakdown of materials by
microorganisms such as bacteria and fungi or other biological activity. Composting is
a human-driven process in which biodegradation occurs under a specific set of
circumstances.(Plastic)
• Example:
• 1. Pseudomonas putida.
• 2. Ideonella sakaiensis.
• 3. Pestalotiopsis microspora

3. PLASTIC
• Plastic created by Hans von pechmann at the accident in 1898.
• A large number of ethylene (C2H4) had on polythene.
• It was creating bonds between nanotube & polymer chains by introducing to
methylene cross linked units.
• Its hydrocarbon which is CH2=CH2 Ethylene have carbon and hydrogen.

4. TYPES OF PLASTIC
• 1. Polyethylene Terephthalate (PETE or PET),
• 2. High-Density Polyethylene (HDPE),
• 3. Polyvinyl Chloride (PVC),
• 4. Low-Density Polyethylene (LDPE),
• 5. Polypropylene (PP),
• 6. Polystyrene or Styrofoam (PS),
• 7. Miscellaneous plastics (includes: polycarbonate, polylactide, acrylic, acrylonitrile
butadiene, styrene, fiberglass, and nylon)

5. PETase
• The first PETase was discovered in 2016 from Ideonella sakaiensis
bacteria found from sludge samples collected close to a Japanese
PET bottle recycling site.
• Cutinase, an esterase enzyme of similar geometric shape
• (Ethylene Terephthalate)n + H2O → (Ethylene Terephthalate)n-1 + MHET

6. PETase WITH MHETase
• The first enzyme of the PET degradation pathway, PETase, cleaves this plastic into
the intermediates major amounts MHET (Mono-(2-hydroxyethyl)terephthalic acid)
and minor amounts BHET (Bis-(2-hydroxyethyl)terephthalic acid).
• The second key enzyme, hydrolyses MHET to the PET educts terephthalate and
ethylene glycol.

7. ENZYMES ACTIVITY
• Now a team at Kyoto University was research for the piles of water. Those researchers
found by microbe a plastic munching microbe. It found after that they were taken by 250
samples that are takin g PLTs.
• It's the isolation of the bacteria name is I. sakaiensis. In this bacterium easily grow.
Some sample was taking for the PET. It is mixed with a bacteria culture. After few
weeks PET has gone. Then will saw a resealed for it is working in the chemical reaction.
This building bond is the ester bond. In the enzyme was built with PETs.
• PETase enzyme breakdown of plastic. PET reaction with PETase enzyme has the water
level also. In the PETase was active only in water. It is reaction produce as an MHET. It
will react plastic then produce an MHET with water. It is will be hydrolysed to the
monomers.

8. ENZYMATIC PET DEGRADATION BY PETase
AND MHETase

9. CONCLUSION
• A large district per day trash in plastic for 428 tones . A small district per day trash
in plastic for 92-98 tones.
• In this plastic can be used to the recycling processed to convert the PET to
terephthalate (88%) and ethylene glycol (12%).
• Reuse of terephthalate or terephthalic acid and ethylene glycol.