Speaker
Description
Since the last century, plastics became indispensable for our everyday life. Nowadays, less than 20% of the global plastic waste is recycled and plastic pollution causes a huge impact on the global ecosystem: prompt action is needed to face one of the most pressing environmental issues [1].
Plastics represent a major challenge for the recycling industry and enzymatic degradation is an innovative and greener alternative to mechanical plastic recycling, allowing to recover valuable monomers that can be re-used for the synthesis of new polymers [2]. Biocatalysts inspired by the great variety of natural hydrolases can be optimized by protein engineering to improve their performance (e.g. thermostability) or tune their activity. Among the most investigated hydrolases, cutinases, which hydrolyze a natural polyester (cutin), have been proposed for the biodegradation and the synthesis of polyesters [3].
Wild type cutinases can be engineered and their activity can be altered through computationally designed mutagenesis [4]. In fact, computational protein design is a powerful tool for tailoring enzymes for specific biotechnological applications. The development of a computational and experimental integrated workflow will allow to design and produce enzymes able to hydrolyze different polymers.
In our approach, a number of hot-spot residues are selected using bioinformatic analysis [5]. Mutants are generated in silico and automatically scored through molecular dynamic simulations and molecular docking, in order to identify proteins with the desired features. The second step is the production and purification of selected mutants to assess the activity and stability and to determine the 3D structure by X-ray crystallography. Experimental results are used to optimize the workflow. After the completion of the iterative process, the “best” virtual mutants are produced in large scale, reducing both the computational cost and the number of experiments, with a clear economic advantage.
The integration of experimental and computational results paves the way to a greener solution to the plastic environmental issue. The innovative and sustainable strategy to design enzymes will represent a convenient alternative, with the potential to revolutionize industrial applications.
[1] PlasticEurope-Association of Plastics Manufactures. Plastics – the Facts 2020. In PlasticEurope. 2020 https://www.plasticseurope.org/en/resources/publications/4312-plastics-facts-2020
[2] B. Zhu, D. Wang, N. Wei. Trends in Biotechnology. 2022, 40(1), 22.
[3] V. Ferrario, A. Pellis, M. Cespugli, G.M. Guebitz, L. Gardossi. Catalysts. 2016, 6, 205.
[4] S. Fortuna, M. Cespugli, A. Todea, A. Pellis, L. Gardossi. Catalysts. 2021, 11, 784.
[5] V. Ferrario, C. Ebert, A. Svendsen, W. Besenmatter, L. Gardossi. Journal of Molecular Catalysis B: Enzymatic. 2014, 101, 7.
