Motivation
The beginning of our project.
Back in May, we first heard about iGEM competition. Our enthusiasm and ambitions led us to the idea of trying to solve global problems by taking small steps and getting closer to success. Lack of knowledge and difficulties we faced didn’t stop us from the goals we had.
Our current project is not the first one we worked on. During the May, we were trying to solve the problem of cellulose deficiency in daily meal consumption in our country.
Unfortunately, it didn’t work out well. After conducting numerous and long-term research, we discovered
the plastic pollution problem. It seemed to be both promising and demanding, and we decided to go for it.
Our main goal was to create a bacteria that would decompose plastic at faster rates. The effort we put into it is indescribable,
and we strongly believe that we will succeed!
Plastic contamination has become one of the most acute environmental problems.
Despite widespread awareness that the over-use and mismanagement of plastic is leading
to global pollution and environmental damage, plastic manufacturing continues to increase rapidly.
Introduction to the Problem
The graph below provides information about worldwide plastic production from 1950 till 2015.
Production increased exponentially, from 2.3 million tons in 1950 to 350 million tons by 2015.
Hazard of Plastic Exploitation
Plastics have transformed the planet’s surface far beyond densely populated areas - soils and lakes,
from the remote shores of the Antarctic Islands to the tropical seabed, and fragments of all sizes are ubiquitous.
Plastics appear in bird nests, are worn by hermit crabs instead of shells, and are present in turtle stomachs.
People generate large amounts of waste, and the amount increases as living standards and populations rise.
Although the amount of waste varies from country to country, approximately 10 percent of solid waste is plastic waste.
Up to 80 percent or sometimes more of the waste that accumulates on land, on the shores, on the ocean surface, or on the seabed is plastic.
Current methods of
Plastic Decomposition
At this point, there are three main methods that are widely used worldwide.
All these recovery methods are usually energy-intensive and expensive. Furthermore, they are not eco-friendly and usually produce toxic by-products.
Plastics are now crucial in many aspects of modern life, for applications including, but not limited to, healthcare, technology, construction,
and clothing productivity. Plastics have significant beneficial properties that are difficult to obtain with other materials, for example, depending on the type of polymer,
can be heated, sterilized, and manipulated by plastics while maintaining their structural properties. However, their cheap and disposable nature often results in their unnecessary use and discard.
Our solution
Our team proposes to use synthetic biology to solve the problem of
plastic contamination. Owing to the development of genetic engineering, it has become possible
to combine the genes of unrelated species, through lab manipulations.
Bioremediation is an option because it is cost-effective and environmentally friendly.
Therefore, researching new effective microorganisms and increasing knowledge about their biology
can pave the way for efficient and feasible plastic bioremediation processes.
Research
In 2016, Japanese scientists Shosuke Yoshida, Kazumi Hiraga, Ikuo Taniguchi, Kohei Oda discovered the bacterium ideonella sakaiensis, which could decompose plastic. Namely, one of the widely used types of plastic PET.
Global production of polyethylene terephthalate (PET) is estimated to reach 87.16 million metric tons by 2022.
Through analysis of the Ideonella genome has shown the presence of two unique enzymes - PETase and MHETase - whose coordinated action is necessary for the hydrolysis of PET.
PETase depolymatizes PET by releasing soluble products including mono(2-hydroxyethyl) terephthalate (MHET), which is broken down into terephthalic acid and ethylene glycol by MHETase.
These enzymes, by working in pairs form SUPER ENZYME, which is able to accelerate the decomposition of the plastic process several times and convert it efficiently into its two environmentally benign monomers.
Stage 1:
PET hydrolase (PETase) hydrolyzes PET into mono(2-hydroxyethyl) terephthalic acid (MHET).
Stage 2:
MHET hydrolase (MHETase) hydrolyzes MHET into terephthalic acid (TPA) and ethylene glycol (EG).
Given all of the above, we have identified the main goal of our project.
The main goal of our project is to create a bacteria that decomposes plastic in Kazakhstan.
Since the ideonella sakaiensis has been found in Japan, where the subtropical climate predominates,
the bacteria will not be able to be used as our country has a sharply continental climate.
Therefore, the aim of the project is to create a bacteria adapted to the climatic conditions of our country.
That’s why we want to use the bacterium Pseudomonas putida.
The bacterium of this genus has the unique ability to quickly adapt to different environmental conditions
due to extremely diverse metabolism and the production of different types of enzymes. We also chose this bacteria,
as it is safe to use and does not harm the environment.
Pseudomonas putida is a Gram-negative, rod-shaped bacterium that can be encountered in diverse ecological habitats.
This ubiquity is traced to its remarkably versatile metabolism, adapted to withstand physicochemical stress,
and the capacity to thrive in harsh environments. Owing to these characteristics, there is a growing interest
in this microbe for industrial use, and the corresponding research has made rapid progress in recent years.
