An economical biorefinery process for propionic acid production from glycerol and potato juice using high cell density fermentation

► Glycerol and potato juice as raw materials for propionic acid production. ► Sequential batch fermentation with cell recycle gives high propionate productivity. ► Highest glycerol concentration of 120 g L−1 consumed to give 78 mol% propionic acid. ► Cost analysis of raw materials shows economical feasibility of the process.