Extractive fermentation for enhanced propionic acid production from lactose by Propionibacterium acidipropionici.
An extractive fermentation process using an amine extractant and a hollow-fiber membrane extractor to selectively remove propionic acid from the fermentation broth was developed to produce propionate from lactose. Compared to the conventional batch fermentation, the extractive fermentation had a much higher productivity ( approximately 1 g/(L.h) or 5-fold increase), higher propionate yield (up to 0.66 g/g or more than 20% increase), higher final product concentration (75 g/L or higher), and higher product purity ( approximately 90%). Meanwhile, acetate and succinate productions in the extractive fermentation were significantly reduced. The improved fermentation performance can be attributed to the reduced product inhibition and a possible metabolic pathway shift to favor more propionic but less acetic and succinic acid production. The process was stable and gave consistent long-term performance over the 1. 5-month period studied. The effects of propionate concentration, pH, and amine content in the solvent on the extractive fermentation were also studied and are discussed in this paper.
Jin
Z
Z
Department of Chemical Engineering, The Ohio State University, Columbus, Ohio 43210, USA.
Yang
S T
ST
D005285:Fermentation; D006863:Hydrogen-Ion Concentration; D007785:Lactose / Q000378:metabolism*; D011422:Propionates / Q000378:metabolism*; D011424:Propionibacterium / Q000378:metabolism*
D011422:Propionates; D007785:Lactose; C029658:propionic acid