PARTITIONING OF DIGESTIVE EXTRACTS FROM ENDEMIC FISHES SPECIES OF PARANA-PARAGUAY BASIN ON PEG-CITRATE AQUEOUS TWO PHASE SYSTEMS

ACEVEDO GÓMEZ, ANTONELLA; VAN DE VELDE, ANDREA; GOMEZ, GABRIELA; BUSTILLO, SOLEDAD; LEIVA, LAURA; NERLI, BIBIANA

Guaruja

Conferencia; 20th Biopartitioning & Purification Conference 2019 (BPP 2019); 2019

Fish viscera constitute about 5?8% of visceral mass and are usually discarded as a waste. These unwanted materials contain proteases (e.g. trypsin) which have an enormous field of industrial applications. Although proteases from various sources have been studied extensively, those of fish have not been fully explored. Polymer/salt aqueous two-phase systems (ATPSs) provide a powerful method for separating biomaterials. Those ATPSs containing biodegradable anions such as citrate are interesting due to their eco-friendly character. The aim of this work was to evaluate viscera extracts of three endemic fish species from Parana-Paraguay basin as potential sources of proteases. In addition, their partitioning properties in ATPSs formed by polyetilenglycol MW 3,350 (PEG3350) and sodium citrate (NaCit), pH 5.0 and pH 8.0, were explored in order to design an extraction strategy. Extracts from pancreatic diffuse tissue, such as pyloric cecae of palometa (Pygocentrus nattereri, a carnivorous fish) and pacú (Piaractus mesopotamicus, omnivorous) and mesentery of surubi (Pseudoplatystoma corruscans, carnivorous) named Pne, Pme and Pce, respectively, were assessed. Total protein (TP), trypsin-like activity (Tryp) and total protease content (Pase) were determined in the extracts and in the phases after partitioning equilibrium. TP of viscera extracts was similar for all species, ranging 0,5-0,6 mg/mL, but Pase and Tryp content showed marked differences between carnivorous (high values) and omnivorous (low value) species. Additionally, Pce exhibit the highest Pase and Tryp activities, probably due to its tissue source (mesentery). Partitioning equilibrium for Tryp was displaced to the top phase in practically all the ATPSs explored. The highest partition coefficient (Kp,Tryp) was observed for the Pce while the lowest values were obtained for the Pme. Distribution of Pase followed a similar trend to Tryp, exhibiting a higher affinity for the polymer-enriched phase but less one-sided. However, a different behavior was observed when TP partitioning was analyzed, since the Kp,TP values resulted close to the unity (0.98-1.68). The selectivity parameter  (Kp,Tryp/Kp,TP or Kp,Pase/Kp,TP), which is representative of the ATPSs ability to separate proteases from other proteins present, showed values highly far from unity, particularly for Pce and Pne. Thus, our results suggest that PEG3350/NaCit ATPS constitute a potential tool at primary recovering of proteases from fish wastes.