title: Optimization of acid protease production by Aspergillus niger I1 on shrimp peptone using statistical experimental design.
abstract: Medium composition and culture conditions for the acid protease production by Aspergillus niger I1 were optimized by response surface methodology (RSM). A significant influence of temperature, KH(2)PO(4), and initial pH on the protease production was evaluated by Plackett-Burman design (PBD). These factors were further optimized using Box-Behnken design and RSM. Under the proposed optimized conditions, the experimental protease production (183.13 U mL(-1)) closely matched the yield predicted by the statistical model (172.57 U mL(-1)) with R(2) = 0.914. Compared with the initial M1 medium on which protease production was 43.13 U mL(-1), a successful and significant improvement by 4.25 folds was achieved in the optimized medium containing (g/L): hulled grain of wheat (HGW) 5.0; KH(2)PO(4) 1.0; NaCl 0.3; MgSO(4)(7H(2)O) 0.5; CaCl(2) (7H(2)O) 0.4; ZnSO(4) 0.1; Na(2)HPO(4) 1.6; shrimp peptone (SP) 1.0. The pH was adjusted at 5 and the temperature at 30°C. More interestingly, the optimization was accomplished using two cheap and local fermentation substrates, HGW and SP, which may result in a significant reduction in the cost of medium constituents.
authors.affiliation: Laboratoire de Génie Enzymatique et de Microbiologie, Ecole Nationale d'Ingénieurs de Sfax, Université de Sfax, BP 1173-3038, Sfax, Tunisia.
authors.forename: Rayda
authors.initials: R
authors.lastname: Siala
authors.forename: Fakher
authors.initials: F
authors.lastname: Frikha
authors.forename: Samiha
authors.initials: S
authors.lastname: Mhamdi
authors.forename: Moncef
authors.initials: M
authors.lastname: Nasri
authors.forename: Alya Sellami
authors.initials: AS
authors.lastname: Kamoun
mesh_terms: D000818:Animals; D001234:Aspergillus niger / Q000187:drug effects / Q000201:enzymology*; D003300:Copper / Q000494:pharmacology; D003470:Culture Media / Q000737:chemistry / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D004795:Enzyme Stability; D005656:Fungal Proteins / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008628:Mercury / Q000494:pharmacology; D008670:Metals / Q000494:pharmacology; D033561:Penaeidae / Q000737:chemistry; D010436:Pepstatins / Q000494:pharmacology; D010447:Peptide Hydrolases / Q000378:metabolism*; D010461:Peptones / Q000737:chemistry / Q000494:pharmacology; D011188:Potassium / Q000494:pharmacology; D011480:Protease Inhibitors / Q000494:pharmacology; D059748:Proteolysis / Q000187:drug effects; D012107:Research Design / Q000706:statistics & numerical data*; D013379:Substrate Specificity; D013696:Temperature
chemical_list: D003470:Culture Media; D005656:Fungal Proteins; D008670:Metals; D010436:Pepstatins; D010461:Peptones; D011480:Protease Inhibitors; D003300:Copper; D010447:Peptide Hydrolases; D008628:Mercury; D011188:Potassium; C031375:pepstatin