The first step was to identify a suitable medium for the cultivation of G. oxydans. The amount of yeast extract and glucose used in the cultivation medium can be reduced. A growth rate of 0.099 h-1 and a doubling time of 7.0 h were determined. To develop the media, the cultivation in minimal medium was also improved. Furthermore, the influence of different yeast extracts on the growth of G. oxydans was investigated. Three equivalent yeast extracts could be identified. Afterwards, various substances were tested to replace CaCO3 in medium. Regarding the cultivation and production with G. oxydans on a large scale, the pH regulation by NaOH could be determined as replacement of CaCO3. For experiments in shaking flasks, the use of CaCO3 turned to be the best performing agent to control pH.
This work was focused on the xylonic acid production in shaking flask with G. oxydans by using pure xylose. In a first experiment, a xylonic acid concentration of 98 g/L could be achieved with a yield of 84 % and 0.82 g/(Lh) volumetric productivity for a cultivation time of 120 h.
Adding xylose during fermentation, resulted in an increased xylonic acid concentration of 347 g/L. With a yield of 77 %, the volumetric productivity was improved to 4.82 g/(Lh).
Studiengang / zentr. Einrichtung:
Biotechnologie / Biopharmazeutische Technologie Bachelor