Designing Enzymes that Recycle Plastic with Birch Biosciences

When you think of plastic recycling, you likely think of mechanical recycling — the process of physically breaking down plastic waste at high temperature and reprocessing it into a new recycled product. 

However, mechanical recycling is expensive, produces high levels of greenhouse gasses, and creates recycled plastic that is often lower quality than its source material. As a result, there is limited circularity in plastic recycling today, and we continue to rely on oil or gas to manufacture most of our plastic products rather than use recycled plastic feedstocks.  

But plastic can also be recycled biologically. Enzymes — catalysts that speed up chemical reactions — have the ability to break down plastic products into small molecules that can be reused to manufacture the same high value plastic products. Though this technology shows promise, it hasn’t been commercialized to date.   

Birch Biosciences has created a platform that can discover, design and optimize enzymes that increase both the sustainability and circularity of plastic recycling. In a new collaboration with the Agile BioFoundry, they will work to develop more efficient enzymes than those currently available. 

Agile BioFoundry’s capabilities will help systematically inform the design of enzymes. The teams will also use biosensors, which detect the production of a metabolite, to quantify the enzymes’ performance. 

The teams hope this work will advance inexpensive and sustainable recycling of polyethylene terephthalate (PET), one of the most widely used plastics that is primarily found in textiles and plastic packing such as single-use bottles. 

“Given that textile manufacturing alone is responsible for 10% of global greenhouse gas emissions — more than aviation and maritime shipping combined — enabling cost-effective and sustainable solutions for circularity in this area could have a major impact on mitigating climate change,” said Johan Kers, CEO and co-founder of Birch Biosciences. 

This collaboration between the Agile BioFoundry and industry is one of five projects totaling over $3 million announced by the U.S. Department of Energy to conduct research and development needed to accelerate the U.S. biomanufacturing sector. The Agile BioFoundry is funded by the U.S. Department of Energy Bioenergy Technologies Office.