Production of aspartic peptidases by Aspergillus spp. using tuna cooked wastewater as nitrogen source and further extraction using aqueous two phase system

Abstract

The production of extracellular aspartic peptidase by the fungi Aspergillus niger and Aspergillus awamori was carried out in a shake flask and in stirred tank submerged fermentations using tuna cooked wastewater, an industrial effluent, as nitrogen source for culture medium. In stirred tank fermentation, biomass production of 6 g/l and 2 arbitrary units was obtained. In addition, the partitioning of extracellular aspartic peptidases from cell-free. A. awamori broth culture produced in a stirred tank reactor was carried out in aqueous-two phase systems formed by polyethylene glycol and potassium phosphate. Previous results showed that aspartic peptidases have a high affinity for the PEG-rich phase. A Kp of 4.5 for ATPS PEG 1450-Pi; in ATPS PEG 8000-Pi, Kp value of the range of 2 to 2.5 was obtained. A purification factor 2 was obtained. The method appears to be suitable as a first step for the purification of these proteins from these complex medium.

Key words: Tuna cooked wastewater, aspartic peptidases, aqueous two-phase system.