The use of microorganisms as producers of nanoparticles involves safe processes from the environmental the point of view and is becoming more and more important in microbial biotechnology. For this purpose, more frequently bacteria, yeasts, fungi, actinomycetes, etc. are used. Therefore, the biologically-made nanostructures offer substantially different properties, such as good adhesion, low toxicity, biocompatibility, making them more valuable for biological applications. The aim of the work was to assess the action of inorganic nanoparticles on the accumulation of biomass and biosynthetic capacity of the Saccharomyces cerevisiae CNMNY18 yeast strain. For the evaluation of the TiO2 and ZnO/MgO nanoparticles action, the given compounds were added to the culture medium of YPD, in a concentration of 0.5...15 mg/L. The experiments have shown that the ZnO/MgO nanoparticles, in a concentration of 10...15 mg/L increases the production of biomass with 20-25% (Fig. 1, a). The analysis of the results of mannoprotein content in Saccharomyces cerevisiae CNMN-Y-18 biomass culture, at the cultivation of YPD medium supplemented with nanoparticles, showed a relative stability. At low concentrations of ZnO/MgO nanoparticles, the yeast culture accumulates almost the same amount of mannoproteins, as well as in standard conditions. At the same time, TiO2 nanoparticles in concentrations of 10 mg/L increase the content of mannoproteins with 23% more than in the control sample. The results regarding the total polysaccharides from Saccharomyces cerevisiae CNMN-Y-18 show that TiO2 nanoparticles of 15 mg/L concentration increase the yeast cell biomass carbohydrate content with 42% (Fig. 1, b).

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Fig. 1. The influence of TiO2 and ZnO/MgO nanoparticles on the accumulation of biomass (a) and carbohydrates content (b) in Saccharomyces cerevisiae CN-MN-Y-18 in dependence of concentration. The studies on the nanoparticle influence on the antioxidant enzymes revealed that the catalase activity increased (with 47%) during culturing the yeasts in medium supplied with ZnO/MgO nanocompound (15 mg/L). The stimulating effect may be explained by the fact that the excess supply of ZnO/MgO may induce oxidative stress, which is expressed by the simultaneous activation of antioxidant enxymes (Fig. 1, b). Thus, the study on influence of inorganic nanoparticles of the Saccharomyces cerevisiae CNMN-Y-18 yeast has established that both the nanoparticles of titanium dioxide, as well as those of the oxides ZnO/MgO, represent elements having a major influence on increasing the content of mannoproteins, carbohydrates, catalase activity and the accumulation of cell biomass. The stimulative character of studied nanoparticles for the Saccharomyces cerevisiae CNMN-Y-18 strain depends on the applied concentration.