African Journal of Biotechnology

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

D Spelzini, B Farruggia, NP Guerra, ML Rua, L Pastrana


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.

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