High Cell Density Culture of Dairy Propionibacterium sp. and Acidipropionibacterium sp.: A Review for Food Industry Applications

Abstract

The dairy bacteria Propionibacterium sp. and Acidipropionibacterium sp. are versatile and potentially probiotic microorganisms showing outstanding functionalities for the food industry, such as the production of propionic acid and vitamin B₁₂ biosynthesis. They are the only food grade microorganisms able to produce vitamin B₁₂. However, the fermentation batch process using these bacteria present some bioprocess limitations due to strong end-product inhibition, cells slow-growing rates, low product titer, yields and productivities, which reduces the bioprocess prospects for industrial applications. The high cell density culture (HCDC) bioprocess system is known as an efficient approach to overcome most of those problems. The main techniques applied to achieve HCDC of dairy Propionibacterium are the fed-batch cultivation, cell recycling, perfusion, extractive fermentation, and immobilization. In this review, the techniques available and reported to achieve HCDC of Propionibacterium sp. and Acidipropionibacterium sp. are discussed, and the advantages and drawbacks of this system of cultivation in relation to biomass formation, vitamin B₁₂ biosynthesis, and propionic acid production are evaluated.

Keywords: Bioprocess technology; Dairy propionic acid bacteria; High cell density culture; Probiotics; Propionic acid; Vitamin B12.

Fig. 1

Metabolism of Propionibacterium sp. using different carbon sources via the Wood-Werkman cycle. Enzymes involved in the propionate pathway: (1) methylmalonyl-CoA:oxaloacetate carboxyltransferase; (2) pyruvate carboxylase; (3) malate dehydrogenase; (4) fumarate hydratase; (5) succinate dehydrogenase; (6) propionyl-CoA:succinate CoA transferase; (7) methylmalonyl-CoA mutase; and (8) methylmalonyl-CoA epimerase. Enzymes involved in the acetate and CO₂ pathway: (9) pyruvate dehydrogenase; (10) phosphate acetyltransferase; (11) acetate kinase. PEP phosphoenolpyruvate (Piveteau, ; Wang & Yang, ; Zhang et al., 2015)

Fig. 2

Bioprocess techniques to obtain high cell density cultures of dairy PAB: (1) cell recycling; (2) fed-batch; (3) perfusion culture; (4) extractive fermentation; (5); (6); and (7) cell immobilization (fixed, expanded, and fibrous bed bioreactors, respectively)