To increase the efficiency of enzymatic hydrolysis reactions of polyethylene terephthalate, the factors affecting the enzymatic hydrolysis of PET should be investigated. These factors can be varied and can vary depending on the circumstances. Various factors such as ambient temperature, ambient pH, buffering power as well as PET crystallinity, and the nature of additives are the most important factors affecting PET enzymatic hydrolysis. In this PETROPROVIDERS article, we want to examine these factors.

What is polyethylene terephthalate? What are its most important uses?

PET polymer appliactions

PET polymer appliactions

Polyethylene terephthalate is the best polymer resin with a polyester structure. Polyethylene terephthalate in the industry is also known by the acronym “PET”. This material, which is used in various industries, has interesting properties. Some of the most important features of polyethylene terephthalate are:

  • Good thermal resistance
  • Good electrical resistance
  • Proper insulation
  • Good moldability
  • Stable and durable structure
  • cheap price
  • High efficiency for producing different products
  • ..

However, this material has many different uses. In industry, PET consumers mix the substance with other substances and then react. This increases the resistance of the final product as well as reduces contamination and unwanted by-products.

It should be noted that Iran has a very interesting market for polyethylene terephthalate. This material was initially produced by different countries and used in various industries. One of the most important applications of PET is the production of plastic bottles. We consume, on average, millions of plastic bottles a day, which are made from PET.

In addition, this material has other uses. Some applications of polyethylene terephthalate are:

  • Production of durable car parts
  • Production of electrical insulation components
  • Production of impact-resistant products
  • Production of durable plastics
  • Production of cosmetics
  • Production of building insulation
  • Production of electrical insulation coatings
  • ..

Therefore, polyethylene terephthalate is one of the most important polymers that we examine in PETROPROVIDERS. Next, we want to say why we need to recycle this material.

Why do we need to recycle polyethylene terephthalate?

We know that the uses of polyethylene terephthalate are very different. This material has many different uses in various industries and for this purpose, it must be recycled after entering the environment. This is because it is produced all over the world; For this reason, its use is done by different people around the world.

Millions of tons of pet waste enter the environment each year, which increases the need for recycling. That’s why we need to recycle PET well, which makes up about a third of all plastics produced.

PET polymer waste

PET polymer waste

To this end, there are various methods for recycling polyethylene terephthalate. But the most important and best way to do this is to use the enzyme method. In the enzymatic method, polymeric materials are converted into target materials using different enzymes.

Polyethylene terephthalate is also a polymer that must be converted to its monomeric components; For this reason, using enzymes, these components can be converted to monomers and then used around the world. Due to the various applications of this material, the use of high-efficiency methods for pet recycling is essential.

For this reason, we must do these methods well. In addition, we must consider the factors affecting the enzymatic hydrolysis of PET. Knowing these factors is very important; Because of the high efficiency of the polyethylene terephthalate recycling reaction, it is possible to use the knowledge of factors affecting the enzymatic hydrolysis of PET.

Why should we use the enzymatic method to recycle polyethylene terephthalate?

In general, there are several methods for recycling polyethylene terephthalate. Using this method reduces PET pollution worldwide, But it should be noted that these contaminants must be removed using appropriate methods. The best way to recycle polyethylene terephthalate is to use the enzymatic method.

In the enzymatic method, unlike other methods, polyethylene terephthalate is not exposed to very high temperatures and does not burn; For this reason, no harmful smoke will be produced. Also, to recycle this substance, the enzymatic method can have much higher efficiency and less time. For this reason, in addition to using the enzymatic method, knowledge about the factors affecting the enzymatic hydrolysis of PET should also be learned.

Mass producers of PET around the world must work with the mass recyclers of this substance. In general, in countries such as Japan and France, polyethylene terephthalate is recycled en masse. This material is recycled by major recyclers in these countries and used to produce new products.

The most important factors affecting the enzymatic hydrolysis of PET

These factors can reduce the inhibition of reactions in the polyethylene terephthalate recycling process. It should be noted that if the use of this material in various industries is well done, its recycling will be done well. It should be noted that the factors that we want to say below are the most important factors that affect the recycling of PET by the enzymatic method.

1. Ambient temperature and PET in enzymatic hydrolysis

On average, an increase in ambient temperature will lead to better decomposition of PET; Because increasing the temperature increases the molecular movement of polyethylene terephthalate materials. As a result, it provides easy access to the ester bonds of this material. In addition, increasing the temperature will increase the flexibility of this material.

It is better to increase the temperature to about 70 to 80 degrees Celsius. But you should keep in mind that PET hydrolyzing enzymes are not damaged at this temperature. The optimum temperature for enzymes is about 70 degrees Celsius.

Experiments have shown that after 94 hours at ambient temperatures of 70 ° C, almost all of the PET decomposes; But if we reduce the temperature to about 50 degrees Celsius, only 5% of PET will decompose! For this reason, in addition to increasing the ambient temperature, heat-sensitive enzymes must also be resistant.

Other experiments have shown that if the test temperature is 80 ° C, about 97% of polyethylene terephthalate will decompose. For this reason, it is recommended to increase the temperature of polyethylene terephthalate as well as the test medium to about 70 to 80 degrees Celsius to recycle this material.

2. A factor called pH, one of the most important factors affecting the enzymatic hydrolysis of PET!

pH Factor

pH Factor

Many PET hydrolysis enzymes are active in alkaline environments, But these enzymes produce acid during activity. Acidic conditions greatly affect the enzymatic hydrolysis of polyethylene terephthalate. For this reason, when recycling polyethylene terephthalate, in addition to increasing the ambient temperature, we must select different effective enzymes to be able to work in both alkaline and acidic pH ranges.

Some enzymes, such as Terrestris, can work in acidic environments in addition to withstanding temperatures above 70 to 80 degrees; For this reason, the use of this enzyme for enzymatic recycling of polyethylene terephthalate is very popular. In addition, there is another factor called buffering properties that the materials we choose must have buffering properties. This property makes polyethylene terephthalate monomers easily degradable and increases their ionic strength in the environment.

3. Crystallinity is very important in PET!

If the crystallinity is low in PET, it will increase the recycling efficiency of this material. If this factor is high, it will increase the compactness of the material as well as its tensile strength. For this reason, different enzymes derived from organisms such as Pseudomonas should be present in the enzymatic recycling process of polyethylene terephthalate.

Some aliphatic polyesters have lower crystallinity compared to semi-aromatic polyesters. For this reason, they can be easily recycled. The story is the same with polyethylene terephthalate! It is better to first select the desired material and perform its crystallinity tests. Then start the hydrolysis recycling reaction of polyethylene terephthalate.

4. One of the most important factors affecting the enzymatic hydrolysis of PET; Properties of enzymes!

There are several characteristics for different types of polyethylene terephthalate enzymes. These features will make the recycling process of polyethylene terephthalate better. For example, if a lower degradation rate is considered for the enzyme, the PET recycling efficiency will be higher.

The different activities of PET hydrolyzing enzymes will also increase or decrease the recovery rate. Given that these characteristics are different in each enzyme, the best enzymes with the best quality should be selected.

Because endo and Exo activities are seen in the amorphous regions of recombinant enzymes, we will see a 50% weight loss of polyethylene terephthalate after 96 hours. After this position, the remaining polyethylene terephthalate will be easily hydrolyzed to monomeric components.

A summary of the factors affecting the enzymatic hydrolysis of PET

In this article, we saw the most important factors affecting the enzymatic hydrolysis of PET. These comparisons show how the efficiency of PET recycling reactions can be increased enzymatically.

In general, several factors are important as factors affecting the enzymatic hydrolysis of PET. In the study of factors affecting the enzymatic hydrolysis of PET, we saw that the ambient temperature, as well as its pH, are very important. In addition, the properties of enzymes are not ineffective in increasing or decreasing the efficiency of polyethylene terephthalate!

For this reason, the use of enzymatic methods to recycle polyethylene terephthalate can be very interesting. The crystallinity of polyethylene terephthalate was another important factor affecting the enzymatic hydrolysis of PET. This property also increases or decreases the recycling efficiency of polyethylene terephthalate.

What do you think about the various factors affecting the enzymatic hydrolysis of PET? Can these enzymes be used to increase the recycling efficiency of polyethylene terephthalate under certain conditions? What is your opinion about the recycling of Iran polyethylene terephthalate? Can this material be easily recycled? Is recycling polyethylene terephthalate harmful to human health?


What are the most important factors affecting the enzymatic hydrolysis of PET?

Ambient temperature, ambient pH, enzyme properties, and polyethylene terephthalate crystallinity are the most important factors affecting the enzymatic hydrolysis of PET.

Are PET Bottles Safe for Me?

Yes! This substance is approved by the FDA and is not harmful to human health.

Why do we need to recycle polyethylene terephthalate?

This material has various applications in different industries. Recycling can reduce environmental pollution as well as increase the production efficiency of new products.

What can we do to buy the best Iran polyethylene terephthalate?

To buy Iran polyethylene terephthalate with the highest quality, you can contact our specialists right now.