title: Enhanced secretion of natto phytase by Bacillus subtilis.
abstract: Phytases comprise a group of phosphatases that trim inorganic phosphates from phytic acid (IP6). In this study, we aimed to achieve the efficient secretion of phytase by Bacillus subtilis. B. subtilis laboratory standard strain 168 and its derivatives exhibit no phytase activity, whereas a natto starter secretes phytase actively. The natto phytase gene was cloned into strain RIK1285, a protease-defective derivative of 168, to construct a random library of its N-terminal fusions with 173 different signal peptides (SPs) identified in the 168 genome. The library was screened to assess the efficiency of phytase secretion based on clear zones around colonies on plates, which appeared when IP6 was hydrolyzed. The pbp SP enhanced the secretion of the natto phytase most efficiently, i.e. twice that of the original SP. Thus, the secreted natto phytase was purified and found to remove up to 3 phosphates from IP6.
authors.affiliation: a Department of Agrobioscience , Kobe University , Kobe , Japan.
authors.forename: Shogo
authors.initials: S
authors.lastname: Tsuji
authors.affiliation: b Organization of Advanced Science and Technology , Kobe University , Kobe , Japan.
authors.forename: Kosei
authors.initials: K
authors.lastname: Tanaka
authors.affiliation: a Department of Agrobioscience , Kobe University , Kobe , Japan.|b Organization of Advanced Science and Technology , Kobe University , Kobe , Japan.
authors.forename: Shinji
authors.initials: S
authors.lastname: Takenaka
authors.affiliation: a Department of Agrobioscience , Kobe University , Kobe , Japan.|b Organization of Advanced Science and Technology , Kobe University , Kobe , Japan.
authors.forename: Ken-ichi
authors.initials: K
authors.lastname: Yoshida
mesh_terms: D010832:6-Phytase / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D000595:Amino Acid Sequence; D001412:Bacillus subtilis / Q000201:enzymology* / Q000235:genetics; D003001:Cloning, Molecular; D010833:Phytic Acid / Q000737:chemistry*; D045730:Soy Foods
chemical_list: D010833:Phytic Acid; D010832:6-Phytase
keywords: Bacillus subtilis; phytase; phytic acid; secretion; signal peptide