3.3. Quantification of phytase activities
Both extracellular and intracellular phytase activities were determined
for strains of P. kudriavzevii at four different time points during
the growth curve: t2, t8, t24 and t48 (Fig. 4). Values of volumetric extracellular
activity ranged from 49.17 to 4.08 mU/ml. For strain G6 and
M30 significant differences were found for the extracellular activity at
t2. Higher values of extracellular activity were measured for strain
G5 at t8 while for strain M31 at t2. Unexpectedly, for all the four strains
the minimum extracellular activity values were detected at t48. By
looking at the intracellular volumetric activity, the values ranged from
42.79 to 2.19 mU/ml. The intracellular activity was significantly higher
at t2 for strain G6 andM30. StrainM31 showed a different pattern of intracellular
activity (Fig. 4). The phytase activity of strain M16 (negative
strain)was significantly lower both at extra and intracellular level compared
to G6, G5, M31 and M30 P. kudriavzevii strains.