Abstract:
Reactive oxygen species are derived from molecular oxygen used in respiration and they are capable of damaging
cellular components, including proteins, lipids and DNA. Oxidative stress is caused by an imbalance between
production of reactive oxygen species and the ability of biological system to detoxify reactive intermediates or to repair
the inflicted damages. The purpose of this paper is the determination of the antioxidant potential in saprophytic fungus
Rhizopus nigricans. It was determined the influence of carbon sources, represented by grinded cereal caryopses, and
their concentration from culture medium on the fungus capacity to synthesize antioxidant enzymes like catalase and
peroxidase. Enzymatic assays were performed at three time intervals: 5, 10 and 15 days, using both fungus mycelium
and culture liquid. After analyzing the results we can point out a correlation between the nature and concentration of
carbon source, the age of fungal culture and the production of oxidoreductases. In the first time period catalase and
peroxidase production is maintained at low levels, but with depletion of nutrients and accumulation of toxic metabolic
byproducts a significant increase takes place in the second time period. The last time period corresponds with the
entering in decline phase of culture and with drastic decrease in production of both enzymes.
