Organic Solvent and Laundry Detergent Stable Crude Protease from Nile Tilapia (Oreochromis niloticus) Viscera

Recovery of alkaline proteinases from fisheries wastes: biochemical characterization and applications

Fish visceral waste, which is normally discarded, is considered one of the richest sources of proteinases with potential biotechnological applications. For this reason, alkaline proteinases from viscera of Argentine hake Merluccius hubbsi, Brazilian flathead Percophis brasiliensis, Brazilian codling Urophycis brasiliensis, and stripped weakfish Cynoscion guatucupa were characterized. Individuals were caught by a commercial fleet off the coast of the Argentinean Sea. The intestine and pyloric caeca were dissected out and then minced and triturated with distilled water. The proteinase activity of P. brasiliensis extracts was enhanced by all the ions tested (Mn2+, K+, Na+, Ca+2) while the enzymes of the other species were stable in the presence of those ions, retaining more than 60% of their enzymatic activity. Alkaline proteinases of all species showed extreme stability to 5% v/v surfactants at 60 min (Sodium dodecyl sulfate, Triton X-100, Tween 20, Tween 80), and relative stability toward an 6% v/v oxidizing agent (H2O2) and organic solvents 80% (acetone, isopropanol, methanol, ethanol). The enzyme extracts were incubated for 60 min with these compounds. Interestingly, alkaline proteinases from all species were compatible with the commercial detergents (Ala, Skip, and Ace). These results demonstrate that proteinases recovered from a no-cost sample such as fishery residues can be used for industrial applications, such as detergent formulations.

Sc-CO2 extraction of fish and fish by-products in the production of fish oil and enzyme

Supercritical carbon dioxide (Sc-CO2) is an alternative tool to extract lipid for the production of fish oil and enzyme from fish by-products (FBPs). In the application of Sc-CO2, this review covers sample preparation, lipid extraction operation, and characterization of fish oil and enzyme as final products. Generally, the fish samples with moisture content less than 20% and particle size less than 5 mm are considered before lipid extraction with Sc-CO2. Sc-CO2 parameters, such as pressure (P), temperature (T), extraction time (text), and flow rate (F), for simultaneous recovery of fish oil, protein, and enzyme were found to be less severe (P: 10.3-25 MPa; T: 25-45 °C, text: 20-150 min; F: 3-50 g/min) than the extraction of fish oil alone (P: 10-40 Mpa; T: 35-80 °C; text: 30-360 min; F: 1-3000 g/min). The enzyme from the Sc-CO2 defatted sample showed higher activity up to 45 U/mg due to lower denaturation of protein as compared to the organic solvent treated sample albeit both samples having similar pH (6-10) and temperature stability (20-60 °C). Overall, mild extraction of lipid from FBPs using Sc-CO2 is effective for the production of enzymes suitable in various industrial applications. Also, fish oil as a result of extraction can be produced as a health product with high polyunsaturated fatty acids (PUFAs) and low contamination of heavy metals.