title: Strain improvement of Pichia kudriavzevii TY13 for raised phytase production and reduced phosphate repression.
abstract: In this work, we present the development and characterization of a strain of Pichia kudriavzevii (TY1322), with highly improved phytate-degrading capacity. The mutant strain TY1322 shows a biomass-specific phytate degradation of 1.26 mmol g-1h-1after 8 h of cultivation in a high-phosphate medium, which is about 8 times higher compared with the wild-type strain. Strain TY1322 was able to grow at low pH (pH 2), at high temperature (46°C) and in the presence of ox bile (2% w/v), indicating this strain's ability to survive passage through the gastrointestinal tract. The purified phytase showed two pH optima, at pH 3.5 and 5.5, and one temperature optimum at 55°C. The lower pH optimum of 3.5 matches the reported pH of the pig stomach, meaning that TY1322 and/or its phytase is highly suitable for use in feed production. Furthermore, P. kudriavzevii TY1322 tolerates ethanol up to 6% (v/v) and shows high osmotic stress tolerance. Owing to the phenotypic characteristics and non-genetically modified organisms nature of TY1322, this strain show great potential for future uses in (i) cereal fermentations for increased mineral bioavailability, and (ii) feed production to increase the phosphate bioavailability for monogastric animals to reduce the need for artificial phosphate fortification.
authors: Department of Biology and Biological Engineering, Food and Nutritional Science, Chalmers University of Technology, SE-412 96, Gothenburg, Sweden.
authors: Linnea
authors: 0000-0003-1722-7693
authors: L
authors: Qvirist
authors: Proteomics Core Facility, Gothenburg University, SE-405 30, Gothenburg, Sweden.
authors: Egor
authors: E
authors: Vorontsov
authors: Department of Biology and Biological Engineering, Food and Nutritional Science, Chalmers University of Technology, SE-412 96, Gothenburg, Sweden.
authors: Jenny
authors: J
authors: Veide Vilg
authors: Department of Biology and Biological Engineering, Food and Nutritional Science, Chalmers University of Technology, SE-412 96, Gothenburg, Sweden.
authors: Thomas
authors: T
authors: Andlid
mesh_terms: D010832:6-Phytase / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*; D001646:Bile; D003470:Culture Media / Q000737:chemistry; D004361:Drug Tolerance; D004795:Enzyme Stability; D000431:Ethanol / Q000633:toxicity; D015966:Gene Expression Regulation, Fungal / Q000187:drug effects*; D006863:Hydrogen-Ion Concentration; D007218:Industrial Microbiology; D009154:Mutation; D010710:Phosphates / Q000378:metabolism*; D010843:Pichia / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism* / Q000528:radiation effects; D013696:Temperature
chemical_list: D003470:Culture Media; D010710:Phosphates; D000431:Ethanol; D010832:6-Phytase