The role of Nisin in the metabolic pathway of lactic acid bacteria

Nisin exhibits multiple synergistic mechanisms with the metabolic pathways of lactic acid bacteria, which are specifically as follows:

Enhancement of Cell Membrane Permeability

Lactic acid bacteria produce acidic substances such as lactic acid during metabolism, reducing the environmental pH. Nisin shows increased solubility, improved stability, and enhanced antibacterial activity under acidic conditions. Meanwhile, substances like lactic acid may alter the structure and properties of the cell membrane, increasing its permeability and allowing nisin to more easily enter the cell interior. This enables nisin to better exert its role in inhibiting bacterial growth. For example, it can bind to specific receptors on the cell membrane, form pores, cause the leakage of intracellular substances, and suppress cell growth.

Regulation of Metabolite Production

The synthesis of nisin is closely related to the metabolism of lactic acid bacteria. During the metabolic process of lactic acid bacteria, some metabolic intermediates can serve as precursor substances for nisin synthesis and participate in its formation. For instance, certain amino acids, peptide segments, etc., may be utilized by lactic acid bacteria to synthesize Nisin. Additionally, the production of nisin can also affect the generation of metabolic products by lactic acid bacteria themselves, potentially prompting lactic acid bacteria to produce more metabolic products with antibacterial or other beneficial properties, thereby enhancing the competitiveness of lactic acid bacteria in the ecological environment.

Inhibition of Heterotrophic Bacteria Growth

Lactic acid bacteria produce various metabolic products during fermentation, such as lactic acid, acetic acid, hydrogen peroxide, etc., which themselves have certain antibacterial effects. Nisin acts synergistically with these metabolic products to more effectively inhibit the growth of heterotrophic bacteria. For example, it can synergize with lactic acid to exert a stronger inhibitory effect on Gram-positive bacteria, reduce the competition of heterotrophic bacteria for nutrients, create a more favorable environment for the growth and metabolism of lactic acid bacteria, enable lactic acid bacteria to better exert their fermentation function, and produce more beneficial metabolic products.

Regulation of Gene Expression

Nisin may affect the expression of genes related to the metabolic pathways of lactic acid bacteria by interacting with certain regulatory factors within lactic acid bacteria cells. On the one hand, it can activate genes related to its own synthesis and promote nisin production; on the other hand, it may also regulate the expression of genes related to other metabolic functions of lactic acid bacteria, adjusting the metabolic pathways of lactic acid bacteria in a direction conducive to their own growth and the production of beneficial metabolic products, thereby improving the fermentation efficiency and product quality of lactic acid bacteria.