Bio-Succinic Acid from Glucose (Direct Crystallization & S. cerevisiae)

The process under analysis comprises two major sections: (1) Fermentation; and (2) Purification.

Fermentation. The culture media used in the pre-fermentation and in the fed-batch fermentation are prepared by diluting the glucose syrup and nutrients in water. The applied recombinant microorganism is propagated in an aerobic pre-fermentation step to obtain the proper inoculum concentration. When there is a sufficient mass of bacteria colony, the microorganism inoculum from the pre-fermentation step is fed into the fermentors. Fed-batch medium is continuously supplied to the fermentors, and the main fermentation is carried out under anaerobic process conditions. CO2 is sparged in the fermentors to provide anaerobic conditions that trigger the bioconversion of the glucose syrup to Succinic Acid, also working as an additional source of carbon. The pH control is made by addition of a solution of ammonia, so as to keep the pH of the fermentation broth around 3.

Purification. After fermentation, biomass is separated from the broth. The clarified broth is then submitted to an ultrafiltration step, used to remove the remaining contaminants. The resulting Succinic Acid solution then passes through distillation, and two successive crystallization and filtration steps for concentration and purification. The final product obtained is 99.9 wt% Succinic Acid.