Organizing co mmittee

 
 

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Poster presentation 
203 
BIODEGRADATION OF POLYETHYLENE TEREPHTHALATE 
(PET) BY PETASE ENZYME 
 
M.M. Nazirov, I.M. Khalilov 
 
Institute of Microbiology of the Academy of Science of the Republic of Uzbekistan,
7b Abdulla Qadiri Street, Tashkent 100128 
Polyethylene terephthalate (PET) is a common polymer that is widely used in a 
variety of consumer products such as water bottles, food packaging, and synthetic 
fibers. PET is convenient due to its inertness, resistance to moisture and chemicals, and 
low cost. However, PET is one of the main sources of plastic waste pollution because it 
is non-biodegradable and can persist in the environment for hundreds of years. 
In recent years, there has been increasing interest in the use of PET biodegradation 
methods. One promising approach involves the use of PET-degrading enzymes, such as 
PETase, produced by certain types of bacteria. 
Research has shown that enzymes can be very effective in breaking down PET. For 
example, in 2016, a bacterium known as 
Ideonella sakaiensis
, isolated from samples 
taken from a plastic bottle recycling plant in Sakai, Japan, was found to use PETase to 
break down PET into monomers. This discovery led to further research into the use of 
PETase as a means of biodegrading PET. 
PETase is an enzyme capable of breaking down PET into its components, including 
terephthalic acid and ethylene glycol. This enzyme works by breaking the ester bonds 
that hold PET together, causing the polymer to depolymerize. 
A potential application of PETase is the development of biodegradable PET 
products. By introducing PETase into the production process, it will be possible to 
create PET products that are naturally biodegradable in the environment and to reduce 
the amount of plastic waste produced. 
Another potential application of PETase is PET processing. Nowadays, PET is 
usually recycled by melting it down and using it to create new products. However, this 
process requires energy and can lead to the formation of harmful byproducts. By using 
PETase to break down PET, a more efficient and environmentally friendly recycling 
process can be created. Even in 2020, it was found that 90 percent of PET can be broken 
down into monomers in 10 hours using the PETase enzyme. 
Despite the potential benefits of PETase, there are several problems associated with 
its use. For example, the PETase enzyme is very sensitive to changes in pH and 
temperature, and a drop in pH is observed when PET decomposes. This leads to enzyme 
inhibition. To solve this problem, in 2022, Hongyuan Lu and a number of scientists 
discovered 
through 
machine 
learning-aided 
engineering 
that 
N233K/R224Q/S121E/D186H/R280A mutations can remain active in a wide pH and 
temperature range of the PETase enzyme. This makes it possible to process PET 
polymer from PETase enzyme on an industrial scale using genetically modified 
bacteria. 
In conclusion, PETase is a promising tool for PET biodegradation. The use of 
PETase can have an important tool in the development of biodegradable PET products 
and PET recycling. Through continued research and development, PETase can become 
a valuable tool to reduce plastic pollution and create a more sustainable future. 

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Poster presentation 
204