Effect of Light Radiation Intensity and the Size of Submicrometer Particles of Heavy Metal Oxides on the Activity of Micromycetes Exooxidoreductases and Their Production of Hydrogen Peroxide

Abstract— The effect of RbTe1.5W0.5O6 complex oxide particles was investigated of different sizes (300 and 700 nm) when exposed to light with different radiant intensity (524 and 325.5 W/m2) on the content of hydrogen peroxide in the culture medium of the fungi Aspergillus brasiliensis and Penicillium chrysogenum, biodegraders of industrial materials, and on the activity of some of their extracellular catalases and peroxidases was investigated. It was found that when heavy metal oxide particles were introduced into the cultivation medium under dark conditions, hydrogen peroxide production decreased in both fungi, with a more pronounced effect observed for particles of smaller size. Under illumination, the inhibitory effect increased; changes in radiation intensity did not play a role. I most cases, addition of particles into the culture medium resulted in the inhibition of extracellular catalase activity. In the case of A. brasiliensis, decreasing the particle size resulted in a more pronounced effect. Particles of the complex oxide RbTe1.5W0.5O6 stimulated the activity of exoperoxidase of both fungi, and more intensively with smaller particle sizes. In most cases, increasing the radiation intensity also increased the activity of exoperoxidase. The obtained data indicate possible adaptive responses in fungi depending on particle size and radiation intensity.