Headimage abstract

New measuring procedure for plastic-degrading enzymes

The metabolising of plastics such as polyethylene terephthalate (PET) with the help of enzymes has been a subject of research for many years. Several enzymes – so-called polyester hydrolases – which occur in bacteria and fungi, can degrade PET plastic up to a certain level. Its further development for industrial use has so far been very time-consuming. A working group headed by Dr. Heinz-Georg Jahnke from the University of Leipzig has developed a new measuring method with which plastic-degrading enzymes could be identified and quantified faster than before, thus significantly accelerating the development of such enzymes.


The development of tailor-made polyester hydrolases for industrial use has until now been very complicated, according to project manager Dr. Heinz-Georg Jahnke, head of the molecular biological-biochemical process engineering group at the University of Leipzig. The problem is that the enzymes have to be repeatedly modified and subsequently tested for their new properties. It can take years until an enzyme has the desired high recycling activity. With the new method developed at the University of Leipzig, it is possible, says Jahnke, to follow and quantify in real time how enzymes degrade the PET. Use is made here of impedance spectroscopy, a process for measuring electrical resistances with which the properties of the material or system can be researched. As a result, according to the report, many specimens can be analysed simultaneously. According to the authors, further advantages are that it is a non-invasive procedure that gets by without markers and does not lead to material losses. They say it is suitable as a basis for building automated measuring systems, with the help of which plastic-degrading enzymes could be developed in high-throughput analyses quickly and with high relevance to practice.

For the research group at the University of Leipzig, the enzymes represent a highly promising approach for the environmentally friendly recycling of PET packaging materials. Unlike with mechanical procedures, the plastic is not contaminated by the enzymatic splitting into individual PET modules, which means that recycling could theoretically be repeated without any loss of quality. With the new process it was also possible, according to the study, to test enzymes that stem from plastic samples of everyday sources such as non-returnable packaging. The new measuring process should also help to speed up the development of multi-recyclable plastics. Together with industry partners, the working group wants to further develop the technology so that it can be used both in research and by companies to search for particularly good enzymes for degrading plastics or to find new, easy-to-recycle plastics.


More information: to the article „Real-Time Noninvasive Analysis of Biocatalytic PET Degradation



  • (Dec. 12, 2021)
  • ASC Publications (Dec. 9, 2021)
  • Photo: ©

Go back