Activity phytases in recombinant strains Yarrowia lipolytica under different conditions of cultivation

The selection of some clones of the recombinant Yarrowia lipolytica yeast producing an encapsulated high-temperature phytase of Obesumbacterium proteus has been performed. The introduction of the pUV3-Op plasmid affected on neither growth parameters nor development of transformants. The maximum phytase activity was rached after 48 hours of cultivation and showed a wide optimal pH range (5.0-7.0). The growth of transformants in the poor medium using low-value plant raw materials (sunflower meal, wheat middling, crushed corn) as the sole source of phosphates has been studied. During the experiment, biomass accumulation, phytase activity and morphology of the Y. lipolytica transformants were tested. Growth in the sunflower meal containing medium was accompanied by a high level of phytase activity and biomass yield while the cultivation in crushed corn containing medium led to significantly lower level of biomass yield and phytase activity. In the cells of transformants grown using the plant phytate-containing substrates the 3-4 fold increase in inorganic phosphate content was observed compared to that in the initial Y. lipolityca yeast. This study let us conclude that the transformed Y. lipolityca Po1f (pUV3-Op) yeast tested is capable of synthesizing phytase when cultivated in phytate-containing media and can be used to produce fodder additives.