Plastic pollution is one of the most significant environmental concerns in the contemporary world. Polyurethane (PU), the 6\(^{th}\) most widely used plastic, contributes to 675,000 tonnes of waste per year in Europe [1]. Conventional waste treatment methods, such as landfilling and incineration, present a threat to the environment. Moreover, mechanical or chemical recycling methods require significant energy consumption and can result in recycled products of inferior quality.
A viable alternative solution for the management of PU waste is microbiological or enzymatic treatment, since the reaction conditions are mild and the degradation products can be used in the production of new PU materials. PU is a suitable candidate for this type of recycling, since it possesses bonds susceptible to hydrolysis, such as ester and urethane bonds. The urethane bond exists in all types of PU, and therefore represents an effective target for the creation of a universal PU recycling method. The cleavage of this bond is performed by urethanases (EC 3.5.1.75) [2]. However, research on these enzymes specifically for PU degradation is currently limited.
The present study is based on a Lysinibacillus sp. urethanase (UTH, GenBank: QCW12854.1), derived from soil collected in Lithuania. The uth gene was expressed in the Escherichia coli expression system. The enzyme was then purified by immobilised metal affinity chromatography and its application in PU degradation was investigated. The products were determined by gas chromatography and liquid chromatography-mass spectrometry. Further details of the study will be presented during the poster session.