Optimization of semi-anaerobic vitamin B12 (cyanocobalamin) production from rice bran oil using Propionibacterium freudenreichii PTCC1674

Abstract

Abstract Vitamin B12 contributes many substantial metabolic cycles in the living organisms. Since human beings cannot produce such co-factor by their metabolism, they have to receive this vitamin from foods and supplements. Dimethylbenzimidazole (DMBI) distinguishes the active form of vitamin B12 from pseudo-vitamin B12. De Novo total biosynthesis of vitamin B12 in the bacteria should include DMBI biosynthesis through riboflavin pathway. Propionibacterium freudenreichii can produce vitamin B12 through anaerobic biosynthesis pathway. As vitamin B12 production by P. freudenreichii is the growth-associated phenomena, the effect of different carbon sources (rice bran oil, argan oil), nutrients (DMBI) and amino acids (L-Serin, L-Tryptophan, l -cysteine, l -Methionine) on the growth of Propionibacterium freudenreichii PTCC1674 (pfre) were investigated. Through the statistical analysis of vitamin B12 production, rice bran oil (RBO) was selected as the sole carbon source. By applying Plackett-Burman method, significant parameters of vitamin B12 production were extracted and optimized based on Box-Behnken design of experiments. RBO, DMBI and CaCl2.2H2O concentrations and temperature were the four main effective parameters of vitamin B12 production. Via implemented response to surface methodology (RSM), the response was optimized to 2.94 mg/L, while 14% increase of vitamin B12 (cyanocobalamin) production was obtained at RBO concentration of 8.648% V/V, temperature of 38.3 (°C), DMBI concentration of 55.758 (mg/L) and elemental solution concentration of 2 (mg/L). It was concluded that pfre can grow on rice bran oil as a new carbon source while the changing of culture media composition alters the growth profile. Box-Behnken design effectively optimized parameters achieved from Plackett-Burman screening method.