Screening For Yeast Phytase Leads to the Identification of a New Cell-Bound and Secreted Activity in Cyberlindnera jadinii CJ2.

Claudia Capusoni,Silvia Donzella,Concetta Compagno,Immacolata Serra

doi:10.3389/fbioe.2021.662598

Claudia Capusoni, Silvia Donzella + Show 2 more

Open Access

https://doi.org/10.3389/fbioe.2021.662598

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Abstract

Phytic acid is an anti-nutritional compound able to chelate proteins and ions. For this reason, the food industry is looking for a convenient method which allows its degradation. Phytases are a class of enzymes that catalyze the degradation of phytic acid and are used as additives in feed-related industrial processes. Due to their industrial importance, our goal was to identify new activities that exhibit best performances in terms of tolerance to high temperature and acidic pH. As a result of an initial screening on 21 yeast species, we focused our attention on phytases found in Cyberlindnera jadinii, Kluyveromyces marxianus, and Torulaspora delbrueckeii. In particular, C. jadinii showed the highest secreted and cell-bound activity, with optimum of temperature and pH at 50°C and 4.5, respectively. These characteristics suggest that this enzyme could be successfully used for feed as well as for food-related industrial applications.

Highlights

Phytic acid is the main source of stored phosphorus in grains, oil seeds, and nuts (Mullaney and Ullah, 2003), typically representing up to 60–80% of total phosphorus in seed, and playing an important role during seed germination and growth (Shi et al, 2005)
Twenty-one yeast species (28 strains) belonging to Debaryomyces, Cyberlindnera, Schizosaccharomyces, Kluyveromyces, Saccharomyces, Brettanomyces, Candida, Torulaspora, Rhodosporidium, Meyerozyma, Hanseniaspora, Pichia, Lachancea, Kazakistania, and Rhodotorula genera were characterized for their ability to grow using phytic acid as sole phosphorus source (Table 1 and Supplementary Figure 1)
All strains except Kluyveromyces lactis Y1356 were able to grow using phytic acid as sole phosphorus source, but with variable extent (Table 1)

Summary

Introduction

Phytic acid (myo-inositol 1,2,3,4,5,6-hexakis dihydrogen phosphate) is the main source of stored phosphorus in grains, oil seeds, and nuts (Mullaney and Ullah, 2003), typically representing up to 60–80% of total phosphorus in seed, and playing an important role during seed germination and growth (Shi et al, 2005). The presence of phytic acid creates problems in breeding, being feeds mainly composed by vegetal materials rich in this acid. Polygastric animals are able to degrade phytate, thanks to their particular gut microbiota (Nakashima et al, 2007), but this process does not occur in the monogastric ones, like poultry, pigs, fishes, and humans. Since phytate cannot be metabolized, feed for monogastric animals are often fortified with inorganic phosphorus, increasing their final cost. Accumulation of phytic acid has a negative effect on animal health, because it represents an anti-nutritional and chelating agent, that reduces bioavailability of proteins and ions like Fe3+, Ca2+, Zn2+, and Mg2+ forming insoluble complexes (Reddy et al, 1982; Coban and Demirci, 2017). Phytate degradation in food is mediated mainly by fermentation processes led by phytate-degrading microorganisms (De Angelis et al, 2003; Rizzello et al, 2010) or during the food processing by endogenous phytases present in food

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