Secretion of non-cell-bound phytase by the yeast Pichia kudriavzevii TY13
Journal article, 2015
AimsMineral 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. Methods and ResultsThe phytase activity in cell-free supernatants from cultures with 100% intact cells was 35-190mUml(-1) depending on the media. The K-m was 028mmoll(-1) and the specific phytase activity 032Umg(-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. ConclusionsOur 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. Significance and Impact of the StudyTY13 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.