Influence of culture temperature on the growth dynamics of Lactobacillus sakei in nutrient media with various protein substrates

Currently, much attention is being paid to the study of natural antimicrobial agents that safely and effectively protect food products from the development of microbiological spoilage. The study of the antimicrobial properties of new, little-studied bacteriocins is an important task and is relevant, in this regard, in recent years attention has been drawn to sakacin, a bacteriocin synthesized by Lactobacillus sakei bacteria. A lyophilized culture of Lactobacillus sakei DSM-20498 was used as the object of the study, as well as a protein substrate of dry enzymatic meat peptone and dry chicken protein extract. The influence of the temperature factor on the growth dynamics and accumulation of Lactobacillus sakei DSM-20498 biomass during deep cultivation on nutrient media with various protein substrates: meat peptone and chicken protein extract. Cultivation was carried out in a laboratory bioreactor with control of key physico-chemical parameters (pH, temperature, mixing rate). It was found that the culture of Lactobacillus sakei DSM-20498 demonstrates high sensitivity to changes in cultivation parameters, including temperature conditions and the composition of the protein substrate. The highest specific growth rate of Lactobacillus sakei DSM-20498 was achieved at a temperature of (32 ± 1) °C. The maximum value of µ (0.63 h-1) and the largest increase in crop biomass (9.0 log CFU/cm3) were observed on nutrient media with meat peptone, characterized by a low molecular weight composition of protein substances. Thus, the temperature (32 ± 1) °C and the use of peptone as a protein source in nutrient media are preferable for the cultivation of Lactobacillus sakei DSM-20498 in order to maximize biomass accumulation.