Editing of the Proteolytic System of Lactococcus lactis Increases Its Bioactive Potential

Area of Science:

• Microbiology and Biotechnology
• Proteomics and Bioinformatics
• Food Science and Nutrition

Background:

• Intracellular peptidomics for bioactive peptide discovery is challenging due to extraction and identification difficulties.
• Lactic acid bacteria (LAB) are crucial in food production and represent a potential source of bioactive peptides.
• The intracellular peptidomes of LAB are largely unexplored reservoirs for novel bioactive peptides.

Purpose of the Study:

• To establish a comprehensive analytical pipeline for large-scale intracellular peptidomics in Lactococcus lactis.
• To identify and characterize bioactive peptides derived from β-casein digestion by L. lactis.
• To investigate the impact of genetic modification of proteolytic systems on bioactive peptide production.

Main Methods:

• Developed an optimized sample preparation and intracellular peptide extraction protocol for L. lactis.
• Created an optimized database of bioactive peptides from bovine β-casein.
• Employed mass spectrometry-based peptidomics to analyze L. lactis MG1363 and its peptidase mutants.

Main Results:

• Observed strain-dependent accumulation of various bioactive peptides, including ACE-inhibitory, DPP-IV-inhibitory, and immunoregulatory peptides.
• Demonstrated that editing the proteolytic system of L. lactis can increase the diversity and quantity of bioactive peptides.
• The developed pipeline successfully identified numerous intracellular peptides with significant bioactivities.

Conclusions:

• The comprehensive peptidomics pipeline facilitates the discovery of intracellular bioactive peptides in L. lactis.
• Targeted genetic engineering of LAB proteolytic pathways can enhance the production of specific bioactive peptides.
• This approach provides a model for exploring bioactive peptide potential in other bacteria and protein sources.