ISSN print edition: 0366-6352
ISSN electronic edition: 1336-9075
Registr. No.: MK SR 9/7
Effectivity of tyrosinase purification by membrane techniques versus fractionation by salting out
Karolina Labus, Łukasz Wiśniewski, Małgorzata Cieńska, and Jolanta Bryjak
Department of Bioprocess and Biomedical Engineering, Wrocław University of Science and Technology, Wrocław, Poland
Received: 4 July 2019 Accepted: 10 January 2020
The main goal of this study was to select micro- and ultrafiltration membranes that can be used for the purification of mushroom tyrosinase, replacing salting-out dual-step processes followed by centrifugations. In experiments, a raw extract from white mushrooms was used with high level of ballast proteins and brownish impurities. Four microfiltration membranes for the removal of undesired high molecular weight compounds were screened and that made of nitrocellulose was selected due to high recovery of enzymatic activity. Then diafiltration and concentration on the membrane made of polyethersulphone (300 kDa) was selected to recover 8% of proteins and 58% of tyrosinase activity with five- to seven purification fold, 10% of proteases, and 8% of brown impurities. It was shown that tyrosinase can be pre-purified by selected membranes yielding the enzyme quality at least comparable to that after double salting-out method but in one device. In both cases, subsequent purification by ion-exchange chromatography slightly increased purification degree of the enzyme and brown impurity removal. The surplus of membrane pre-purification is substantially higher thermal stability of the enzyme, enlarged after the chromatographic step, due to very low content of proteolytic enzymes.
Keywords: Tyrosinase purification; Membrane separation; Chromatography; Enzyme stability
Full paper is available at www.springerlink.com.
Chemical Papers 74 (7) 2267–2275 (2020)