Recycling plastic bottles and transform them into valuable alternative products is one of the biggest challenges nowadays. According to a 2016 report by the World Economic Forum, plastics lose 95% of their material value after a single-use. Besides that, plastic pollution is one of the most pressing environmental issues facing globally. Indeed, about 1 million plastic bottles are sold every minute around the world and just 14% are recycled.
Therefore it is important to find new incentives and methods to make the recycling process more attractive and effective.
Now, a group of researchers from the University of Edinburgh has developed a method to convert plastic bottles into vanilla flavoring.
Plastic bottles recycling: can you make vanilla out of plastic?
What are the raw materials of plastic bottles?
Plastic bottles are commonly made up of synthetic polymers derived from fossil fuels. These polymers include:
- Polyethylene terephthalate (PET).
- Low- and high-density polyethylene (LDPE/HDPE).
- Polypropylene (PP).
- Polycarbonate (PC).
Transforming Polyethylene terephthalate (PET) into vanillin
Polyethylene terephthalate (PET) is an abundant material. Carbonated beverages, water, and food products employ it because it is a strong and light material. Despite recycling technologies for post-consumer PET waste exist, there is an urgent need to develop technologies to make it more lucrative.
Thus, researchers Stephen Wallace and Joana Sandler developed a method to use genetically engineered E. coli bacteria to transform terephthalic acid (TA), a compound of PET, into vanillin.
Vanillin is the principal component responsible for the characteristic taste and smell of vanilla. The food and cosmetic industries use it broadly and there is a high demand in the industry. Finally, the research, published in the journal Green Chemistry, found a way to process PET derived monomer terephthalic acid into the value-added small molecule vanillin:
Maximizing the efficiency of Vanillin production
The microbial synthesis of vanillin from Polyethylene terephthalate (PET) waste developed in different stages:
- Finding the best conditions: first, they needed to find the best conditions to grow the bacteria. Thus, they kept the bacteria at 37 degrees Celsius for a day.
- Cell permeabilization: second, they needed to “convince” E.coli bacteria to metabolize the plastic. So, they used small amounts of alcohol to increase cell permeabilization.
- Maximize vanillin recovery: to conclude, they developed a way to maximize vanillin recovery by using an oleyl alcohol overlay. It has been proved that an oleyl alcohol overlay minimizes product loss due to evaporation and reduces toxicity, which could damage the bacteria.
Finally, after process optimization, researchers succeeded to convert 79% of TA into vanillin.
| What exactly is vanillin? |
Vanillin or vanilla flavor can be obtained from natural sources (vanilla beans) or synthetic methods (synthetic vanillin). However, industries prefer synthetic methods to be more sustainable as the demand grows. Note that the global vanillin market size might reach USD 724.5 million by 2025, according to a new report by Grand View Research, Inc.
Recycling plastic bottles using REVALUO WtE system
The previous work demonstrates the fact that it is possible to obtain actual value from plastic waste. Furthermore, it opens new paths to future applications that improve sustainability and move towards a circular economy.
At Landfill Solutions, we also want to contribute to a more sustainable future. REVALUO WTE system transforms plastic waste into a myriad of value-added products:
In addition, our system is a non-burn technology (NBT) for waste management. Thanks to that it manages to reduce carbon emissions by a minimum of 4g/h per tonne of waste