title: Overexpression of the phytase from Escherichia coli and its extracellular production in bioreactors.
abstract: The gene for phytase from Escherichia coli was sequenced and compared with the appA gene. It was found to be a mutant derivative of the appA gene. After fusion with a C-terminal His-tag, phytase was purified by affinity chromatography and the enzymatic properties were analyzed. To develop a system for overexpression and extracellular production of phytase in E. coli, factors affecting the expression and secretion such as promoter type, host strain and selection pressure were analyzed. Using a secretion system based on the controlled expression of the kil gene, the expression of phytase was improved and the enzyme was released into the culture medium at a high level. An effective fermentation strategy based on fed-batch operation was developed.
authors.affiliation: Department of Fermentation Engineering, Faculty of Technology, University of Bielefeld, 33501 Bielefeld, Germany. gmi@fermtech.techfak.uni-bielefeld.de
authors.forename: G
authors.initials: G
authors.lastname: Miksch
authors.forename: S
authors.initials: S
authors.lastname: Kleist
authors.forename: K
authors.initials: K
authors.lastname: Friehs
authors.forename: E
authors.initials: E
authors.lastname: Flaschel
mesh_terms: D010832:6-Phytase / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D000135:Acid Phosphatase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D000595:Amino Acid Sequence; D001483:Base Sequence; D019149:Bioreactors; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000235:genetics; D005285:Fermentation; D007700:Kinetics; D008969:Molecular Sequence Data; D009154:Mutation; D016133:Polymerase Chain Reaction; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics
chemical_list: D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; D011994:Recombinant Proteins; D000135:Acid Phosphatase; D010832:6-Phytase; C406788:appA protein, E coli