Volume 2 • Issue 1 • 1000108 Enz Eng ISSN: EEG, an open access journal Research Article Open Access Zhao et al., Enz Eng 2013, 2:1 DOI: 10.4172/2329-6674.1000108 Research Article Open Access Keywords: Fish waste; Pepsinogen; Extraction; Purifcation; Fractionation; Enzyme activity; Protein concentration; Recovery yield Introduction Atlantic Canada has 15% (40,000 km) of the Canada’s coastline and 42% of the Canada’s fresh water (320,000 km 2 ). About 80% of total fsh landings come from the Atlantic fshery, while the Pacifc fshery accounts for up to 16% [1]. In 2010, Atlantic Canada’s total sea fsheries landings were 788,599 t/y, with the total value of 1.3 billion dollars. A large portion of the fsh (80%) landed in Atlantic Canada is processed [2]. Tere are three major common steps in fsh processing: (a) removing the viscera, (b) removing the head, tail, fns and skin, and (c) removing the frame and producing fllets. A large fraction (30-80%) of fsh (fesh, heads, bones, fns, skin, tails and viscera) is generated as waste during fsh processing [3,4]. Fish wastes are usually disposed of in landflls or poured directly into the sea, which results in high disposal cost and causes environmental problems. About 56% of the fsh landing in Canada is converted into waste; of which 13% is disposed in the ocean [5]. Conventional disposal of fsh wastes underscores the need for a more reasonable utilization approach of fsh wastes, as well as efective recovery of valuable ingredients from these wastes. Fish wastes can be utilized as animal feed ingredients, as well as organic fertilizers [6,7]. Te recovery of valuable biomolecules, such as collagen [8-11], ω-3fatty acids [12], trypsin [13,14], chymotrypsin [15-17], and elastase [18], have also been reported. Among the valuable products that can be recovered from fsh, pepsin is one of the abundant and useful biomolecules that can be efectively recovered from fsh viscera. Pepsin is synthesized and secreted in the gastric membrane in an inactive state called Pepsinogen (PG) (molecular weight of 40 kDa). Pepsin is an important acidic protease, widely applied in the hydrolysis of proteins in the food and manufacturing industries. It can be used in collagen extraction [19-21], gelatin extraction [22], cheese making [23], and regulating digestibility [24]. Extraction of pepsins from fsh viscera not only signifcantly reduces the capital costs of enzyme production, but also partially improves the economics of the fsh processing industry, while minimizing the environmental impact of waste disposal [25,26]. Pepsin, as well as its zymogen, pepsinogen (PG), has been widely purifed from several fsh species, including arctic fsh capelin (Mallotus villosus) [27], rainbow trout (Salmo gairdneri) [28], Atlantic cod (Gadus morhua) [29], bolti fsh (Tilapia nilotica) [7], Antarctic rock cod (Trematomus bernacchii) [30], sea bream (Sparuslatus houttuyn) [31], African coelacanth (Latimeria chalumnae) [32], Mandarin fsh *Corresponding author: Abdel E Ghaly, Department of Process Engineering and Applied Science, Dalhousie University, Halifax, Nova Scotia, Canada, Tel: 902- 494-6014; E-mail: abdel.ghaly@dal.ca Received March 01, 2013; Accepted March 02, 2013; Published March 10, 2013 Citation: Zhao L, Budge SM, Ghaly AE, Brooks MS, Dave D (2013) Partition of Pepsinogen from the Stomach of Red Perch (Sebastes marinus) by Aqueous Two Phase Systems: Effects of PEG Molecular Weight and Concentration. Enz Eng 2: 108. doi: 10.4172/2329-6674.1000108 Copyright: © 2013 Zhao L, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Abstract Fish processing waste can be used to produce commercially valuable by-products, such as pepsinogen, which has application in food, manufacturing industries, collagen extraction, gelatin extraction, and in regulating digestibility. An important acidic protease, pepsin, is synthesized and secreted in the gastric membrane in an inactive state called pepsinogen (PG). In the present study, the purifcation of pepsinogen from the stomach of red perch, using aqueous two phase systems (ATPS) formed by polyethylene glycol (PEG) and salt at 4 ° C, was optimized.The effects of PEG molecular weight (PEG 1000, 1500, 3000 and 4000) and concentration (16, 18, 20, 22 and 24%) on the partitioning of PG were studied, and parameters including total volume (TV), volume ratio (V R ), total enzyme activity (A E ), protein content (C p ), specifc enzyme activity (SA), partition coeffcient (K p ), purifcation fold (PF), and recovery yield (RY) were evaluated. PEG molecular weight and PEG concentration also had signifcant effects on each parameter. TV and V R decreased with increased salt concentration, since salt formed hydrogen bonds with water molecules and formed a more compact and ordered water structure. PG partitioned predominantly in the PEG-rich top phase due to its negative charge. A E , C P , SA, PF and RY increased with increased salt concentration and then decreased, while K P had an opposite pattern. The PEG 3000 (20%), PEG 1000 (24%), PEG 4000 (16%) and PEG 1000 (18%) concentrations gave the highest TV, V R , C P and K P , respectively. PEG 1500 with 18% concentration gave the highest A E, SA, PF and RY (86.2%) . As PEG 1500 at 18% concentration gave the highest RY (86.2%). It was selected as the optimum PEG molecular weight and PEG concentration. (NH 4 ) 2 SO 4 at 15%, which gave the highest RY (71.7%), was selected as the optimum salt type and salt concentration. 15% (NH 4 ) 2 SO 4 18% PEG 1500 was the optimal ATPS combination, and presented a better partition. The values of SA and PF and RY obtained with ATPS method were much higher (2 fold in case of SA and PF, and 1.2 fold in case of RY), than those obtained with the Ammonium Sulphate Fractionation (ASF) method. Partition of Pepsinogen from the Stomach of Red Perch (Sebastes marinus) by Aqueous Two Phase Systems: Effects of PEG Molecular Weight and Concentration Lisha Zhao, Suzanne M Budge, Abdel E Ghaly*, Marianne S Brooks and Deepika Dave Department of Process Engineering and Applied Science, Faculty of Engineering, Dalhousie University, Halifax, Nova Scotia, Canada E n z y m e E n g i n e e r i n g ISSN: 2329-6674 Enzyme Engineering