Development of Stabilized Thermobifida fusca Cutinases for Improved PET Degradation

Abstract

Biodegradation of polyethylene terephthalate (PET), which is the basis for many consumer plastics, has been an area of great interest recently with regards to plastic recycling. Several bacterial enzymes have been discovered that have low-level PET degradation activity. However, this activity must be increased and enzyme functionality at higher temperatures must be achieved before biodegradation techniques can become impactfully utilized for environmental plastic biodegradation. Using machine learning predictions and sequence alignments in the design process, amino acid mutagenesis was performed on the cutinase from Thermobifida fusca. Activity was analyzed through degradation assays with a BHET substrate, and two promising mutants, pKG2 and pKG3, were observed to have significant activity at 70 °C.