Pyloric caeca of Piaractus mesopotamicus as a source of alkaline proteases

GÓMEZ GN; LEIVA LCA; NERLI BB; ACEVEDO GÓMEZ,A.

Natal

Simposio; SIMPÓSIO INTERNACIONAL DE MOLÉCULAS BIOATIVAS E BIOPROCESSOS DE ORGANISMOS AQUÁTICOS; 2017

Universidade Federal do Rio Grande do Norte

Introduction: Piaractus mesopotamicus, commonly known as Pacú, Pez chato, Mirabí or Pirarí, is an omnivorous fish endemic to the Paraguay-Paraná river basin that it has been incorporated to the aquaculture production system in the northern region of Argentina and in the central-west Brazilian area. Fish viscera (processing waste) are rich in peptidases, such as trypsin, widely used in several industries. Objective: This work aimed to characterize alkaline proteases extracted from processing waste. Material and methods: Alkaline extract from the pyloric caeca of pacú was prepared and the optimum conditions of activity and stability were determined, using BApNA (Nα-Benzoyl-L-arginine 4-nitroanilide) as substrate. In that sense, the effect of pHs; temperature; salt concentration; presence of inhibitors, oxidizing agents and surfactants; and compatibility with commercial detergents was evaluated. Results and discussions: Maximal protease activity of the pyloric caeca extract was observed at pH 8.0 and 9.0. The extract was stable over a range of pH from 8.0 to 10.0. Highest activity was found at 45°C. The activity was reduced to 89% at 60°C and was completely lost at 75°C. It was thermostable over a broad temperature range (0-60°C). An addition of 10 mM CaCl2 and MgCl2 did not produce change in the activity. This proteolytic extract remained stable in the presence of non-ionic (Tween 20 and Tween 80) and ionic surfactant (SDS). It also revealed high resistance when incubated with 5 and 15% H2O2 for 45 min. The extract was partially inhibited by phenylmethylsulphonyl fluoride (PMSF). Furthermore, the preparation retained around 100% of its BApNA activity after incubation for 1 h at 40°C with commercial detergents. Conclusions: These results provide the basis for obtaining an attractive protease preparation, potentially applicable as additive for laundry detergents, from an usually discarded product such as the pyloric caeca.