Identification of esterase in Aspergillus flavus during degradation of polyester polyurethane 1

Abstract

Polyurethane not only has applications including tires and insulation, but also is an essential element of our lives. Based on previous reports, some strains of fungus including Pestalotiopsis microspora have been reported to degrade this plastic. The ultimate objective is to create a genetically engineered variant of Pichia pastoris which will digest polyester polyurethane (PUR) using the enzyme responsible for PUR degradation from Aspergillus flavus; this year we aim to identify the esterase, believed to be responsible for the biodegradation. The degradation of TPU (a granular form of thermoplastic PUR) and water-based PUR by A. flavus, was tested using incubation with shaking for one month. Although no significant weight loss was observed, the fungus was capable of growing on the water-based PUR as a food source. Esterase, the enzyme responsible for the degradation of the water-based PUR, was observed in the water-based PUR lane of the Native PAGE gel and has a molecular weight of approximately 20 kDa. Since the only difference between the experimental water- based lane and experimental TPU lane, was the esterase band, it can be confirmed that the degradation of the plastic and growth of fungus can be attributed to the esterase. (English) [ABSTRACT FROM AUTHOR]