title: Aspergillus oryzae S2 alpha-amylase production under solid state fermentation: optimization of culture conditions.
abstract: Aspergillus oryzae S2 was assayed for alpha-amylase production under solid state fermentation (SSF). In addition to AmyA and AmyB already produced in monitored submerged culture, the strain was noted to produce new AmyB oligomeric forms, in particular a dominant tetrameric form named AmyC. The latter was purified to homogeneity through fractional acetone precipitation and size exclusion chromatography. SDS-PAGE and native PAGE analyses revealed that, purified AmyC was an approximately 172 kDa tetramer of four 42 kDa subunits. AmyC was also noted to display the same NH2-terminal amino acid sequence residues and approximately the same physico-chemical properties of AmyA and AmyB, to exhibit maximum activity at pH 5.6 and 60 °C, and to produce maltose and maltotriose as major starch hydrolysis end-products. Soyabean meal was the best substitute to yeast extract compared to fish powder waste and wheat gluten waste. AmyC production was optimized under SSF using statistical design methodology. Moisture content of 76.25%, C/N substrate ratio of 0.62, and inoculum size of 10(6.87) spores allowed maximum activity of 22118.34 U/g of dried substrate, which was 33 times higher than the one obtained before the application of the central composite design (CCD).
authors.affiliation: Laboratory of Microorganisms and Biomolecules (LMB), Centre of Biotechnology of Sfax (CBS), University of Sfax, Road of Sidi Mansour Km 6, PO Box 1177, Sfax 3018, Tunisia.
authors.forename: Mouna
authors.initials: M
authors.lastname: Sahnoun
authors.affiliation: Laboratory of Microorganisms and Biomolecules (LMB), Centre of Biotechnology of Sfax (CBS), University of Sfax, Road of Sidi Mansour Km 6, PO Box 1177, Sfax 3018, Tunisia.
authors.forename: Mouna
authors.initials: M
authors.lastname: Kriaa
authors.affiliation: Laboratory of Microorganisms and Biomolecules (LMB), Centre of Biotechnology of Sfax (CBS), University of Sfax, Road of Sidi Mansour Km 6, PO Box 1177, Sfax 3018, Tunisia.
authors.forename: Fatma
authors.initials: F
authors.lastname: Elgharbi
authors.affiliation: Laboratory of Microorganisms and Biomolecules (LMB), Centre of Biotechnology of Sfax (CBS), University of Sfax, Road of Sidi Mansour Km 6, PO Box 1177, Sfax 3018, Tunisia.
authors.forename: Dorra-Zouari
authors.initials: DZ
authors.lastname: Ayadi
authors.affiliation: Laboratory of Microorganisms and Biomolecules (LMB), Centre of Biotechnology of Sfax (CBS), University of Sfax, Road of Sidi Mansour Km 6, PO Box 1177, Sfax 3018, Tunisia. Electronic address: samir.bejar@cbs.rnrt.tn.
authors.forename: Samir
authors.initials: S
authors.lastname: Bejar
authors.affiliation: Laboratory of Microorganisms and Biomolecules (LMB), Centre of Biotechnology of Sfax (CBS), University of Sfax, Road of Sidi Mansour Km 6, PO Box 1177, Sfax 3018, Tunisia.
authors.forename: Radhouane
authors.initials: R
authors.lastname: Kammoun
mesh_terms: D000332:Aerobiosis / Q000187:drug effects; D000704:Analysis of Variance; D001236:Aspergillus oryzae / Q000187:drug effects / Q000201:enzymology*; D018929:Cell Culture Techniques / Q000379:methods*; D002851:Chromatography, High Pressure Liquid; D004591:Electrophoresis, Polyacrylamide Gel; D004795:Enzyme Stability / Q000187:drug effects; D005285:Fermentation / Q000187:drug effects; D006813:Humidity; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007700:Kinetics; D009584:Nitrogen / Q000494:pharmacology; D015203:Reproducibility of Results; D013213:Starch / Q000378:metabolism; D013696:Temperature; D013997:Time Factors; D014131:Trace Elements / Q000032:analysis; D000516:alpha-Amylases / Q000096:biosynthesis* / Q000378:metabolism
chemical_list: D014131:Trace Elements; D013213:Starch; D000516:alpha-Amylases; D009584:Nitrogen
keywords: Alpha-amylase; Central composite design; Cost-effective; Form; Soyabean meal