Evaluation of the role of different concentrations of folic acid on ascorbate peroxidase activity, catalase, temperature and pH variations and vitamin B12 production in Propionibacterium freudenreichii

Propionibacterium, a gram-positive, anaerobic to micro-aerobic and rod-shaped bacterium, belongs to the propionic bacterial family. Propionibacteria are involved in the production of vitamin B12. The aim of this study was to evaluate the effect of physicochemical parameters (temperature and pH) as well as measurement of ascorbate peroxidase and catalase enzyme concentrations and to investigate changes in vitamin B12 production at different concentrations of folic acid in Propionibacterium freudenreichii. Propionibacterium freudenreichiiwas cultured in fermented medium containing corn and various concentrations of folic acid. The results showed that the optimum pH for the bacterial growth was 6.6 and the optimum bacterial growth at 25-40 °C. Addition of folic acid at low concentrations to the media of Propionibacterium freudenreichiiincreased UV absorption at 600 nm. High folic acid concentrations were found to decrease growth rate, indicating a negative effect of folic acid on bacterial growth. Catalase and ascorbate peroxidase activity was also determined based on H2O2 consumption at 240 and 290 nm. Due to the increase in folic acid concentration, the activity of catalase and ascorbate peroxidase was significantly reduced in this bacterium. Also in the study of vitamin B12 production, considering the bacterial dry weight, using HPLC in anaerobic and aerobic conditions, it was found that the maximum production of vitamin B12 in 750 mg/l folic acid under aerobic conditions. As the concentration of folic acid increased by up to 1000 mg/L, vitamin B12 production decreased.