The increasing demand for propionic acid (PA) production and its wide applications in several industries,
especially the food industry (as a preservative and satiety inducer), have led to studies on the low-cost
biosynthesis of this acid. This paper gives an overview of the biotechnological aspects of PA production and
introduces
Propionibacterium
as the most popular organism for PA production. Moreover, all process variables
influencing the production yield, different simple and complex carbon sources, the metabolic pathway of
production, engineered mutants with increased productivity, and modified tolerance against high
concentrations of acid have been described. Furthermore, possible methods of extraction and analysis of this
organic acid, several applied bioreactors, and different culture systems and substrates are introduced. It can be
concluded that maximum biomass and PA production may be achieved using metabolically engineered
microorganisms and analyzing the most significant factors influencing yield. To date, the maximum reported
yield for PA production is 0.973 g·g
-1, obtained from
Propionibacterium acidipropionici
in a three-electrode
amperometric culture system in medium containing 0.4 mM cobalt sepulchrate. In addition, the best
promising substrate for PA bioproduction may be achieved using glycerol as a carbon source in an extractive
continuous fermentation. Simultaneous production of PA and vitamin B
12 is suggested, and finally, the
limitations of and strategies for competitive microbial production with respect to chemical process from an
economical point of view are proposed and presented. Finally, some future trends for bioproduction of PA are
suggested.
