Affiliation: Technische Universität München, Chair of Chemistry of Biogenic Resources, Schulgasse 16, D- 94315 Straubing, Germany.
The effects of selected yeast extract (YE) compounds on 2,3-butanediol production by Paenibacillus polymyxa DSM 365 were studied. The intention was to substitute complex sources of nutrients by defined compounds thus reducing the high demand of YE as well as lowering the costs of fermentation media. For this purpose the depletion of different inorganic compounds during cultivations was analyzed. Then, their impact on product synthesis (acetoin and 2,3- butanediol) was investigated in shake flasks by systematic replenishing with inorganic compounds to a basal medium containing 5 g L-1 YE. Calcium was found to be a key element to enhance product synthesis. In a similar way, studies on mixtures of 8 vitamins and of 12 amino acids, resp., were done. The best results were established for the combination of inorganics (calcium, zinc and permanganate salts) and vitamins. With the enriched medium the product formation could be enhanced by 67% after 48h compared to the product formation using basal medium. Furthermore, a synthetic medium for 2,3-butanediol production was developed as a basis for further studies.