Journal
JOURNAL OF BIOTECHNOLOGY
Volume 374, Issue -, Pages 90-100Publisher
ELSEVIER
DOI: 10.1016/j.jbiotec.2023.08.001
Keywords
Lactic acid bacteria; Lactobacillus bulgaricus; Kinetic model; Cytosolic pH; Intracellular pH; Lactose metabolism
Categories
Ask authors/readers for more resources
The fermentation process of milk to yoghurt using Lactobacillus delbrueckii subsp. bulgaricus in co-culture with Streptococcus thermophilus is characterized by lactose breakdown and acidification, which impairs metabolic activities and microbial growth. A proton-dependent computational model was developed to understand the metabolic impact of acidification, and simulation results showed a decrease in metabolic flux with acidification of the cytosol.
The fermentation process of milk to yoghurt using Lactobacillus delbrueckii subsp. bulgaricus in co-culture with Streptococcus thermophilus is hallmarked by the breakdown of lactose to organic acids such as lactate. This leads to a substantial decrease in pH - both in the medium, as well as cytosolic. The latter impairs metabolic activities due to the pH-dependence of enzymes, which compromises microbial growth. To quantitatively elucidate the impact of the acidification on metabolism of L. bulgaricus in an integrated way, we have developed a protondependent computational model of lactose metabolism and casein degradation based on experimental data. The model accounts for the influence of pH on enzyme activities as well as cellular growth and proliferation of the bacterial population. We used a machine learning approach to quantify the cell volume throughout fermentation. Simulation results show a decrease in metabolic flux with acidification of the cytosol. Additionally, the validated model predicts a similar metabolic behaviour within a wide range of non-limiting substrate concentrations. This computational model provides a deeper understanding of the intricate relationships between metabolic activity and acidification and paves the way for further optimization of yoghurt production under industrial settings.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available