Process for the production of fermentation broth with increased vitamin

Abstract

The invention relates to a process for the production of a fermentation broth with increased vitamin B.sub.12 content by a fermentation process carried out with a methane-producing mixed bacterium population under anaerobic septic conditions in the presence of known nutrient components and precursors. According to the invention, methanol, preferably in an amount of 0.5 v/v %, is added for some days, preferably for 3 days to the fermentation broth containing vitamin B.sub.12 used as the starting substance. Thereafter a minor part, preferably 10% of the fermentation broth, is removed and an equal volume of a nutrient broth containing the usual components in tenfold concentrations is added periodically in every 5th to 12th day, then the removal of fermentation broth is interrupted for 0 to 2 days, preferably for 1 day, and only 0.4 to 1.5 v/v% of methanol are added to the fermentation broth, and subsequently a minor part, preferably 10% of the fermentation broth, is removed daily and an equal volume of a nutrient broth containing the usual components in the usual concentrations is added together with 0.4 to 1.5 v/v % of methanol, depending on the biogas production of the fermentation broth. This series of operations is repeated periodically during the complete fermentation procedure taking into consideration the pH of the fermentation broth.