title: Production, purification and characterization of an aspartic protease from Aspergillus foetidus.
abstract: An acidic thermostable protease was extracellularly produced either in shake flask or in stirred tank bioreactor by an Aspergillus foetidus strain isolated from the Brazilian savanna soil using different nitrogen sources. Its maximum activity (63.7 U mL-1) was obtained in a medium containing 2% (w/v) peptone. A cultivation carried out in a 5.0 L stirred-tank bioreactor provided a maximum protease activity 9% lower than that observed in Erlenmeyer flasks, which was obtained after a significantly shorter (by 16-29%) time. Protease purification by a combination of gel-filtration chromatography resulted in a 16.9-fold increase in specific activity (248.1 U g-1). The estimated molecular weight of the purified enzyme was 50.6 kDa, and the optimal pH and temperature were 5.0 and 55 °C, respectively. The enzyme was completely inhibited by pepstatin A, and its activity enhanced by some metals. According to the inhibition profiles, it was confirmed that the purified acid protease belongs to the aspartic protease type. These results are quite promising for future development of large-scale production of such protease, which can be useful in biotechnological applications requiring high enzyme activity and stability under acidic conditions.
authors.affiliation: Department of Biochemical and Pharmaceutical Technology, University of São Paulo, Brazil; Departments of Pharmacy, Health Sciences School, University of Brasilia, Brazil. Electronic address: paulasouza@unb.br.
authors.forename: Paula Monteiro
authors.initials: PM
authors.lastname: Souza
authors.affiliation: Departments of Pharmacy, Health Sciences School, University of Brasilia, Brazil.
authors.forename: Gabriela
authors.initials: G
authors.lastname: Werneck
authors.affiliation: Department of Civil, Chemical and Environmental Engineering, Pole of Chemical Engineering, Genoa University, Italy.
authors.forename: Bahar
authors.initials: B
authors.lastname: Aliakbarian
authors.affiliation: Laboratory of Biochemical Process, Agroenergy Embrapa, Brazil.
authors.forename: Felix
authors.initials: F
authors.lastname: Siqueira
authors.affiliation: Laboratory of Enzymology, Department of Cellular Biology, University of Brasilia, Brazil.
authors.forename: Edivaldo Ximenes
authors.initials: EX
authors.lastname: Ferreira Filho
authors.affiliation: Department of Civil, Chemical and Environmental Engineering, Pole of Chemical Engineering, Genoa University, Italy.
authors.forename: Patrizia
authors.initials: P
authors.lastname: Perego
authors.affiliation: Department of Civil, Chemical and Environmental Engineering, Pole of Chemical Engineering, Genoa University, Italy.
authors.forename: Attilio
authors.initials: A
authors.lastname: Converti
authors.affiliation: Departments of Pharmacy, Health Sciences School, University of Brasilia, Brazil.
authors.forename: Pérola Oliveira
authors.initials: PO
authors.lastname: Magalhães
authors.affiliation: Department of Biochemical and Pharmaceutical Technology, University of São Paulo, Brazil.
authors.forename: Adalberto Pessoa
authors.initials: AP
authors.lastname: Junior
mesh_terms: D057055:Aspartic Acid Proteases / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D001230:Aspergillus / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification; D001938:Brazil; D004795:Enzyme Stability; D005656:Fungal Proteins / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D008970:Molecular Weight; D012988:Soil Microbiology; D013379:Substrate Specificity; D013696:Temperature
chemical_list: D005656:Fungal Proteins; D057055:Aspartic Acid Proteases
keywords: Acid protease; Aspergillus foetidus; Purification; Submerged fermentation