Ideonella sakaiensis is a bacterium identified in 2016 that is capable of breaking down PET plastic. It was isolated from samples taken outside a plastic bottle recycling facility in Sakai, Osaka Prefecture, Japan. Genome sequencing of I. sakaiensis identified two key enzymes, PETase and MHETase, that allow it to break the ester bonds in PET plastic, converting it into its basic monomers. While I. sakaiensis shows promise for biodegrading PET plastic, further research is needed to improve its abilities and apply its enzymes to develop more efficient plastic recycling methods.
2. POLYETHYLENE TEREPTHALATE (PET)
• PET is widely used in plastic
bottles like Carbonate drinks,
water bottles, plastic film,
microwavable packaging.
56
6.13
PET was produced worldwide in 2013
Recycling
million tons
7. Ideonella sakaiensis
• I. sakaiensis was identified in 2016 by a
team of researchers from Kyoto Institute
of Technology and Keio University,
Japan.
• The bacterium was named from
environmental samples taken in
Sakai, Osaka Prefecture, it was given
the name Ideonella sakaiensis, strain
201-F6 .
• It is capable of breaking down PET
plastic which was isolated from outside
a plastic bottle recycling facility.
.
8. Morphology
1) A Gram-stain-negative 2) Aerobic
3) Non-spore-forming 4) Rod-shaped bacterium
5)Feed on PET and grew within the pH range 7–7.5 and at 30–
37 ºC
SEM image of Ideonella sakaiensis
9. Discovery
• Researchers collecting a variety of
environmental samples of PET debris.
• They were taken and test tubes
containing a defined culture medium
supplemented with a PET film as the
major carbon source.
• After 6 weeks, sample contained a
distinct microbial which had formed on
the PET film, and the film was showing
clear signs of degradation.
• It is successfully isolated the bacterium
capable of degrading PET.
13. Protein Sequencing Alignment
ISF6_4831
• It encodes a putative
lipase (PETase) that
shares amino acid
sequence identity
and catalytic
residues with a
hydrolase enzyme
(TfH ) from
thermophilic
actinomycete and
cutinase homolog
from leaf-branch
(Lcc)
14. Protein Sequencing Alignment
ISF6_0224
• It is protein
sequence encoded
to (MHETase) and
matches to the
tannase family,
which is known to
hydrolyze the
ester linkage of
aromatic
compounds.
15. PCR-DGGE analysis
• Used to identify bacteria
strain.
• DGGE profiles of 16S
rDNA of microbial
consortia The arrow
indicates the band
corresponding to
I. sakaiensis 201-F6.
16. RNA-Seq transcript levels of ISF6_4831 and ISF6_0224 on
four different carbon sources
• I. sakaiensis was grown in
medium containing
maltose, TPA-Na, PET film,
or BHET), and the mRNAs
from exponentially growing
cells were subjected to
RNA-Seq analysis.
17. Mechanisms of hydrolysis
• Terephthalic acid,
used principally as a
precursor to
the polyester PET
used to make
clothing and plastic
bottles..
18. Future Recommendation
• Improve the bacterium to make it more powerful, and
genetic engineering might be applicable.
• One way of speeding things up would be to transfer the
genes that make the two enzymes into a faster growing
bacterium like Escherichia coli
19. Inquires..!!
• Is there any possibility for the bacteria to be more
abundant in any other regions in the world??
• Can there be any additional applications to maximize the
benefits of such ability??
• Is it possible to identify similar strains which similar
abilities??
20. Conclusion
• PET is used in plastic products, and its accumulation in the
environment has become a global concern.
• (PETase and MHETase) are required to enzymatically convert
PET efficiently into its two environmentally benign
monomers,terephthalic acid and ethylene glycol.
• PET degradation using microorganisms and enzymes
consumes less energy and is a more environmentally friendly
option.
• Researches achieving an ideal model for PET recycling, so
long as we are able to enhance the activity level and stability
of these newly discovered microbial enzymes.
PET is made from petroleum and is widely used in plastic bottles like Carbonate drinks, water bottles, peanut butter jars, plastic film, microwavable packaging.
The amount recycled accounts for just 37% of the total production volume of PET bottles (6.13 million tons)
About 56 million tons of PET was produced worldwide in 2013 alone
15.4 million tons were for food and liquid containers, 3.2 million tons for packaging films, and 38 million tons for synthetic fibers.
Currently the main method employed for recycling PET waste uses chemical techniques, but these processes come with many problems, such as the vast amount of energy consumed.
Researchers collecting a variety of environmental samples of PET debris in a search for bacteria which relied on the plastic for carbon growth.
They were taken and test tubes containing a defined culture medium supplemented with a PET film as the major carbon source.
The bacterium was observed to utilize two distinct enzymes that reacted with water to break down plastics
After 6 weeks, one sediment sample contained a distinct microbial consortiumwhich had formed on the PET film, and the film was showing clear signs of degradation.
From the microbial consortium, we then successfully isolated the bacterium capable of degrading PET.
The bacterium was observed to utilize two distinct enzymes that reacted with water to break down plastics
It has the ability to break down the PET polymer by 2 enzymes (PETase and MHETase
Protein is responsible for hydrolyzes PET,that yield MHET
Hydroxyethyl terephthalic acid (MHET)
Protein is responsible for the conversion of MHET
to TPA and EG in I. sakaiensis
(left, a consortium with PET degradation activity; right, a consortium without PET degradation activity) were compared.
