title: Phytase-producing capacity of yeasts isolated from traditional African fermented food products and PHYPk gene expression of Pichia kudriavzevii strains.
abstract: Phytate is known as a strong chelate of minerals causing their reduced uptake by the human intestine. Ninety-three yeast isolates from traditional African fermented food products, belonging to nine species (Pichia kudriavzevii, Saccharomyces cerevisiae, Clavispora lusitaniae, Kluyveromyces marxianus, Millerozyma farinosa, Candida glabrata, Wickerhamomyces anomalus, Hanseniaspora guilliermondii and Debaryomyces nepalensis) were screened for phytase production on solid and liquid media. 95% were able to grow in the presence of phytate as sole phosphate source, P. kudriavzevii being the best growing species. A phytase coding gene of P. kudriavzevii (PHYPk) was identified and its expression was studied during growth by RT-qPCR. The expression level of PHYPk was significantly higher in phytate-medium, compared to phosphate-medium. In phytate-medium expression was seen in the lag phase. Significant differences in gene expression were detected among the strains as well as between the media. A correlation was found between the PHYPk expression and phytase extracellular activity.
authors.affiliation: Università di Torino, Dipartimento di Scienze Agrarie, Forestali e Alimentari, Grugliasco, Torino, Italy. Electronic address: anna.greppi@unito.it.
authors.forename: Anna
authors.initials: A
authors.lastname: Greppi
authors.affiliation: Department of Food Science, Food Microbiology, Faculty of Science, University of Copenhagen, Denmark.
authors.forename: Łukasz
authors.initials: Ł
authors.lastname: Krych
authors.affiliation: Università di Torino, Dipartimento di Scienze Agrarie, Forestali e Alimentari, Grugliasco, Torino, Italy.
authors.forename: Antonella
authors.initials: A
authors.lastname: Costantini
authors.affiliation: Università di Torino, Dipartimento di Scienze Agrarie, Forestali e Alimentari, Grugliasco, Torino, Italy.
authors.forename: Kalliopi
authors.initials: K
authors.lastname: Rantsiou
authors.affiliation: Département de Nutrition et Sciences Alimentaires, Faculté des Sciences Agronomiques, Université d'Abomey-Calavi, Benin.
authors.forename: D Joseph
authors.initials: DJ
authors.lastname: Hounhouigan
authors.affiliation: Department of Food Science, Food Microbiology, Faculty of Science, University of Copenhagen, Denmark.
authors.forename: Nils
authors.initials: N
authors.lastname: Arneborg
authors.affiliation: Università di Torino, Dipartimento di Scienze Agrarie, Forestali e Alimentari, Grugliasco, Torino, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: Cocolin
authors.affiliation: Department of Food Science, Food Microbiology, Faculty of Science, University of Copenhagen, Denmark.
authors.forename: Lene
authors.initials: L
authors.lastname: Jespersen
mesh_terms: D010832:6-Phytase / Q000235:genetics* / Q000378:metabolism*; D005516:Food Microbiology; D015966:Gene Expression Regulation, Fungal; D010710:Phosphates / Q000378:metabolism; D010833:Phytic Acid / Q000378:metabolism; D010843:Pichia / Q000201:enzymology* / Q000235:genetics*; D060888:Real-Time Polymerase Chain Reaction; D015003:Yeasts / Q000201:enzymology* / Q000235:genetics* / Q000302:isolation & purification
chemical_list: D010710:Phosphates; D010833:Phytic Acid; D010832:6-Phytase
keywords: African fermented food products; Phytase; Phytate; Pichia kudriavzevii; RT-qPCR