Towards Valorization of Bovine Blood Plasma: Optimal Design of a Culture Medium Based on Bovine Blood Plasma with Enzymatically Hydrolyzed Proteins for the Growth of a Probiotic Bacterium by Submerged Fermentation

Bovine blood plasma (BBP), a waste stream from some slaughterhouses, represents an alternative feedstock to be used as a nitrogen source for microbial cultivation. The objective of this research was to evaluate the feasibility of producing Lactobacillus plantarum by submerged fermentation on a laboratory scale in different culture media based on protein BBP hydrolyzates. Six protein hydrolyzates from BBP were obtained using commercial alkaline protease to prepare liquid media with different contents of assimilable nitrogen in a 3-L glass reactor with a water recirculation jacket. L. plantarum ATCC 8014 was cultivated in those media with contents of assimilable nitrogen from 582 to 1097 mg/L, and sucrose from 20 to 80 g/L up to a time of 60 h. The response volume methodology and a numerical optimization method were used to find the optimal values of these variables. Optimal treatment maximizing the viable cell concentration of L. plantarum is associated with a sucrose concentration of 80 g/L, an amino nitrogen content of 825 mg/L, and a culture time of approximately 34 h. The obtained results are relevant for the future design of a biotechnological process for BBP valorization to obtain starter cultures for the meat industry.