Identification and characterization of a polyurethanase with lipase activity from Serratia liquefaciens isolated from cold raw cow's milk

• Published in: Food chemistry 2021-02, Vol.337, p.127954, Article 127954
• Main Authors: Salgado, Cleonice Aparecida, Almeida, Felipe Alves de, Barros, Edvaldo, Baracat-Pereira, Maria Cristina, Baglinière, François, Vanetti, Maria Cristina Dantas
• Format: Article
• Language: English
• Subjects: Animals; Bacterial Proteins - isolation & purification; Bacterial Proteins - metabolism; Biotechnological applications; Cattle; Chromatography, Gel; Chromatography, Liquid; Deterioration; Family I.3 lipase; Fatty Acids - metabolism; Female; Lipase - isolation & purification; Lipase - metabolism; Milk - microbiology; Molecular Docking Simulation; Polyurethanase; Protein Conformation; Serratia liquefaciens - enzymology; Tandem Mass Spectrometry; Urethane - metabolism
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2020.127954

•Serratia liquefaciens produces a lipase that has been identified as polyurethanase.•65 kDa alkaline polyurethanase shows the conserved domain of family I.3 lipase.•Assays with BME, DTT, PMSF, and DEPC confirm that it is a family I.3 lipase.•In silico, polyurethanase uses catalytic serine (GXSXG) to bind to substrates. Lipases are associated with food spoilage and are also used in various biotechnological applications. In this study, we sought to purify, identify, and characterize a lipase from S. liquefaciens isolated from cold raw cow's milk. The lipase partially purified by ultrafiltration and gel filtration showed a specific activity of 2793 U/mg. By zymography, the enzyme presented approximately 65 kDa, and LC-MS/MS allowed the identification of a polyurethanase with a conserved domain of family I.3 lipase. The modeled and validated structure of polyurethanase was able to bind to different fatty acids and urethane by molecular docking. The polyurethanase showed optimum activity at pH 8.0 and 30 °C. In the presence of ions, activity was decreased, except for Ca2+, Mg2+, and Ba2+. Reducing agents did not alter the activity, while amino acid modifiers reduced enzyme activity. It is concluded that polyurethanase with lipase activity represents a potential enzyme for the deterioration of milk and dairy products, as well as a candidate for industrial applications.