Investigation of Physicochemical Parameters and Measurement of Ascorbate Peroxidase and Catalase Activity in the Presence of Different Concentrations of Folic Acid in Propionibacterium freudenreichii

Propionibacterium is a gram-positive genus, anaerobic to microaerophilic, and rod-shaped from propionic bacteriaceae family that is capable of producing propionic acid using transcarboxylase enzymes. The aim of this study was to investigate the effect of physicochemical parameters (temperature and pH) and ascorbate peroxidase and catalase levels at different concentrations of folic acid in Propionibacterium freudenreichiii to produce better and more vitamin B12. The Propionibacterium freudenreichii was inoculated into fermented medium containing soaked corn. Folic acid was added to the fermentation medium at different concentrations, then its absorption at 600 nm, at different temperatures and pH, was investigated. The results revealed that, the optimum pH for bacterial growth was 6.6 and the optimum bacterial growth was at 25-40 °C. Addition of folic acid at lower concentrations to the culture medium of Propionibacterium freudenreichii increased the UV absorption at 600 nm. It was found that, high concentration of folic acid reduced the growth rate which, indicating the negative effect of the folic acid on bacterial growth. Catalase and ascorbate peroxidase activity was determined based on H2O2 consumption at 240 nm and 290 nm. In this bacterium, CAT and ascorbate peroxides activity decreased significantly with increasing folic acid concentration. It was also found that folic acid functioned as a toxin for this bacterium at high concentrations and demonstrated antioxidant properties.