Biosynthesis of propionic acid using whey and calcium carbonate by mixed culture of Propionibacterium freundenreichii ATCC 6207 and Lactobacillus paracasei

Abstract

The microbial production of valuable chemical feedstocks from renewable carbon sources has received increased attention by science and industry. The objective of this work was to study the biosynthesis of propionic acid (PA) by a mixed culture of Propionibacterium freundenreichii ATCC 6207 and Lactobacillus paracasei subsp. paracasei from whey cheese. The effects of L. paracasei inoculum, lactose and calcium carbonate (CaCO3) concentrations on propionic acid (PA) production by P. freundenreichii were investigated following a central composite rotational design with 18 treatments, using whey as source of carbon and nitrogen. Fermentation assays were carried out in Erlenmeyer flasks incubated at 30 °C without shaking during 120 h and for each treatment a kinetic study was done. A production of 23 g L−1 of propionic acid was obtained. Concentrations of lactose below 40 g L−1 and above 30 g L−1 of CaCO3 promoted higher PA production, productivity and yield and acetic acid production. This mixed culture can efficiently use whey for PA biosynthesis, reducing environmental damage from traditional synthesis.