Extraction and purification of enzymes from the Southern eagle ray (Myliobatis goodei) by-products and their compatibility with detergents: A practical approach towards circular economy

Abstract

Nowadays, the need to simultaneously achieve the valorization and recovery of fishing waste is critical for addressing environmental challenges and promoting resource sustainability. Fishing waste hosts enzymes that hold the potential for extraction and utilization in various industries. In this sense, the aim of this work was to extract and purify enzymes from the gastrointestinal tract of Myliobatis goodei using low-cost processes. The proteolytic and lipolytic activities of the extracted enzymes were also investigated. In addition, the detergent compatibility of the purified enzyme extract was evaluated to determine its potential application as an additive in laundry soaps. The crude extract was obtained by homogenization of 100g gastrointestinal tract in buffer Tris-HCl (pH=8.0). Then, it was precipitated with ammonium sulfate and purified by filtration. Finally, it was subjected to centrifugation at 10,000 ×g for 30 min at 4°C in an ultrafilters membrane with a 100 kDa cut-off. This purification protocol showed good performance for proteases and lipases as their activity was recovered at each step. The proteolytic activity was assayed using azocasein as substrate at pH 8.0 and 40°C, while trypsin activity was analyzed against the specific substrate benzoyl-arginine-p-nitroanilide. The lipolytic activity was carried out by p-nitrophenol production through the reaction of pnitrophenylacetate dissolved in 2-propanol at pH 7.0 and 37°C. The compatibility of the enzyme activity with some commercial detergents was evaluated. Additionally, proteolytic and lipolytic activities were tested on spiruline and soybean oil stains and showed a strong ability to remove them from cotton fabrics. Due to its promising properties, the purified enzymes isolated from the gastrointestinal tract of M. goodei may be considered as a potential effective active ingredient for its use in the detergents industry.