Increasing lactose concentration is a strategy to improve the proliferation of Lactobacillus helveticus in milk.

The aim of the research was to explore the effect of carbon sources on the proliferation of Lactobacillus helveticus. In this study, lactose was added to skim milk medium and the effects of carbon sources on the growth and proliferation of Lactobacillus helveticus in low- and high-sugar media were compared from the aspects of metabolism-related enzyme activity, proteomics, and transcriptomics. The results showed that under high-sugar conditions, the rate of substance transport to cells and the Embden-Meyerhof-Parnas (EMP) pathway were significantly accelerated. The synthesis and metabolism of cells were significantly enhanced, which was beneficial to the rapid proliferation of cells. By increasing the lactose concentration in the medium and optimizing the culture method, the cell density of Lactobacillus helveticus reached 3.98 × 109 CFU/ml; a good proliferation effect was obtained.