Lysozyme was partially purified from hen egg white by precipitation of non-lysozyme protein impurities during incubation in the presence of ethanol. The thermal stability of the obtained partially purified enzyme was also characterized. | Turk J Agric For 31 (2007) 125-134 © TÜB‹TAK Partial Purification of Hen Egg White Lysozyme by Ethanol Precipitation Method and Determination of the Thermal Stability of Its Lyophilized Form Seyhun GEM‹L‹2, Emin Selahattin UMDU2, Nilgün YAPRAK2, Fatma Ifl›k ÜSTOK3, Fatih Yalç›n Günefl YENER3, Çi¤em MEC‹TO⁄LU GÜÇB‹LMEZ4 , Sacide ALSOY ALTINKAYA2, Ahmet YEMEN‹C‹O⁄LU1,* 1 Department of Food Engineering, Faculty of Engineering, ‹zmir Institute of Technology, 35430 Gülbahçe Köyü, Urla, ‹zmir - TURKEY 2 Department of Chemical Engineering, Faculty of Engineering, ‹zmir Institute of Technology 35430, Gülbahçe Köyü, Urla, ‹zmir - TURKEY 3 Biotechnology and Bioengineering Program, ‹zmir Institute of Technology, 35430, Gülbahçe Köyü, Urla, ‹zmir - TURKEY 4 Agricultural Directorate of Lüleburgaz District, Ministry of Agriculture and Rural Affairs, Lüleburgaz, K›rklareli - TURKEY Received: Abstract: Lysozyme was partially purified from hen egg white by precipitation of non-lysozyme protein impurities during incubation in the presence of ethanol. The thermal stability of the obtained partially purified enzyme was also characterized. The incubation of diluted egg white for 2-8 h in the presence of 20% ethanol was not very effective for the partial purification of lysozyme by precipitation of major egg white proteins; however, 4- to 6-h or 6- to 8-h incubation of diluted egg white in the presence of 30% and 40% ethanol could be employed more effectively for partial purification of lysozyme. Without applying the incubation period, the highest specific activity was obtained by the treatment of egg white with 40% ethanol. Thus, ethanol at this concentration could be used for a continuous process of partial purification. For batch lysozyme purification, on the other hand, incubation in the presence of 30% ethanol was more appropriate. The activities and protein contents of dialyzed and lyophilized enzymes obtained by 6 h-incubation in the presence of 20%, 30%, and .
