title: Biosynthesis, purification and some properties of extracellular phytase from Aspergillus carneus.
abstract: Aspergillus carneus (Van Tiegh) Blockwitz synthesized moderate quantities of phytase in culture filtrate. Maximal enzyme yield was obtained after eight days incubation statically in a medium containing sucrose and K2HPO4 in a C/P ratio of 591.8/1 with 0.1% corn steep liquor (CSL) as the sole source of nitrogen. Substitution of (NH4)2SO4 with certain amino acids decreased phytase yields significantly. Addition of fish or soybean meal to the nitrogen-free medium failed to enhance phytase production. The enzyme was purified about 43-fold from the culture filtrate by precipitation with acetone, gel filtration through Sephadex G-75 and ion exchange chromatography on DEAE-cellulose. Activity of both crude and purified phytase was influenced greatly by changing of pH and reaction temperature: maximum activity of the crude enzyme occurred at 35 degrees C and pH 5.6, whereas that of the purified preparation at 40 degrees C and pH 5.6. The pure enzyme was found stable between pH 5.6-6.2. About 68% of the enzyme activity was lost by heating at 45 degrees C for 60 min. The pure phytase retained its activity over a long period when stored at 4 degrees C.
authors.affiliation: Biology Department, Faculty of Education, Ain Shams University, Roxy, Cairo, Egypt.
authors.forename: M
authors.initials: M
authors.lastname: Ghareib
mesh_terms: D010832:6-Phytase / Q000096:biosynthesis* / Q000302:isolation & purification / Q000378:metabolism; D001230:Aspergillus / Q000201:enzymology*; D002848:Chromatography, DEAE-Cellulose; D002850:Chromatography, Gel; D005110:Extracellular Space / Q000201:enzymology; D006863:Hydrogen-Ion Concentration; D013696:Temperature
chemical_list: D010832:6-Phytase