title: Secretion of non-cell-bound phytase by the yeast Pichia kudriavzevii TY13.
abstract: OBJECTIVE
  Mineral deficiencies cause several health problems in the world, especially for populations consuming cereal-based diets rich in the anti-nutrient phytate. Our aim was to characterize the phytate-degrading capacity of the yeast Pichia kudriavzevii TY13 and its secretion of phytase.
  
  
  RESULTS
  The phytase activity in cell-free supernatants from cultures with 100% intact cells was 35-190 mU ml(-1) depending on the media. The Km was 0.28 mmol l(-1) and the specific phytase activity 0.32 U mg(-1) total protein. The phytase activity and secretion of extracellular non-cell-bound phytase was affected by the medium phosphate concentrations. Further, addition of yeast extract had a clearly inducing effect, resulting in over 60% of the cultures total phytase activity as non-cell-bound.
  
  
  CONCLUSIONS
  Our study reveals that it is possible to achieve high extracellular phytase activity from the yeast P. kudriavzevii TY13 by proper composition of the growth medium.
  
  
  CONCLUSIONS
  TY13 could be a promising future starter culture for fermented foods with improved mineral bioavailability. Using strains that secrete phytase to the food matrix may significantly improve the phytate degradation by facilitating the enzyme-to-substrate interaction. The secreted non-cell-bound phytase activities by TY13 could further be advantageous in industrial production of phytase.
authors: Department of Chemical and Biological Engineering, Food Science, Chalmers University of Technology, Gothenburg, Sweden.
authors: A
authors: A
authors: Hellström
authors: L
authors: L
authors: Qvirist
authors: U
authors: U
authors: Svanberg
authors: J
authors: J
authors: Veide Vilg
authors: T
authors: T
authors: Andlid
mesh_terms: D010832:6-Phytase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D005110:Extracellular Space / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D007700:Kinetics; D010833:Phytic Acid / Q000378:metabolism; D010843:Pichia / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics
chemical_list: D005656:Fungal Proteins; D010833:Phytic Acid; D010832:6-Phytase
keywords: Pichia kudriavzevii; extracellular; food fermentation; phytase; phytate; yeast