Effects of Different Metallic Nanoparticles on Germination and Morphology of the Fungus Rhizopus oryzae 1526 and Changes in the Production of Fumaric Acid

Abstract

The present study was undertaken to investigate the impact of different concentrations (200–1000 μg/mL) of micro- and nanoparticles of ZnO, Fe3O4 and MnO2 on spore germination and morphology of the fumaric acid (FA)-producing fungus Rhizopus oryzae 1526. Production profile of FA was also investigated as a response to micro- and nanoforms of these compounds. Glucose-basic salts media was used for the growth and FA production. Different incubation conditions were applied for growth (30 °C, 200 rpm and 24 h) and FA production (30 °C, 200 rpm and 72 h). Control experiments were designed without the micro- and nanoforms of the inorganic compounds. At 200 μg/mL of micro- and nanoparticles of ZnO, Fe3O4 and MnO2, percent of spore germination obtained were almost same (96–98 %) as control experiments, except microparticles of MnO2 (85 %). Higher concentrations (>200 μg/mL) of the micro- and nanoparticles caused inhibition in spore germination. The fungus exhibited changes in the pellet size and morphology at different concentrations of the particles. FA production was also influenced by micro- and nanoparticles of ZnO, Fe3O4 and MnO2. Overall, Fe3O4 was found to be the most biocompatible in both micro- and nanoform. Findings of the present research work suggested that the three essential cations (Zn2+, Fe2+/3+ and Mn2+) can have different impacts on the fungus when applied as micro- and nanoformulations.