Purification of Alpha-Amylase Produced by Aspergillus niger CNMN FD 06 under Submerged Cultivation in the Presence of TiO2 Nanoparticles and the Coordination Compound of Sr(II) with Polydentate Ligand

The stimulatory effect of TiO₂ nanoparticles and the coordination compound of Sr(II) with a polydentate ligand on the amylase activity was established under submerged cultivation of the micromycete strain Aspergillus niger CNMN FD 06. After purification by gel-filtration on the column of PAD-10 and the ion exchange chromatography on the Hi-Trap^TM Q column, an increase in the specific activity of α-amylase in the case of the variants with the addition of TiO₂ nanoparticles and coordination compound of Sr(II) up to 15 523 and 14 656 U/mg, respectively, compared to the control version 12 037 U/mg was established. The yield of α-amylases after purification was also higher, with an increase of 31 and 20%, respectively, compared to that of control variant. The SDS-PAGE analysis of the isolated proteins revealed the presence of two bands in the active fractions with an apparent molecular mass equal to 65 and 40 kDa, with a more abundant band with a molecular mass of 65 kDa in the case of the preparation obtained with the addition of the Sr(II) coordination compound.