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Production of bioactive peptides (BAPs) by Lactobacillus species is a cost-effective approach compared to the use of purified enzymes. In this study, proteolytic Lactobacillus helveticus strains were used for milk fermentation to produce BAPs capable of inhibiting angiotensin converting enzyme (ACE). Fermented milks were produced in bioreactors using batch mode, and the resulting products showed significant ACE-inhibitory activities. However, the benefits of fermentation in terms of peptide composition and ACE-inhibitory activity were noticeably reduced when the samples (fermented milks and non-fermented controls) were subject to simulated gastrointestinal digestion (GID). Introducing an ultrafiltration step after fermentation allowed to prevent this effect of GID and restored the effect of fermentation. Furthermore, an integrated continuous process for peptide production was developed which led to a 3 fold increased peptide productivity compared to batch production. Using a membrane bioreactor allowed to generate and purify in a single step, an active ingredient for ACE inhibition.

International audience; To compensate for their amino acid auxotrophy, lactobacilli have developed the ability to hydrolyze proteins present in their environment. This proteolytic activity not only generates the free amino acids needed by the bacteria, but also a large variety of peptides, some of which are endowed with biological activities. These so-called "bioactive peptides" (BAPs) are interesting from a nutrition and healthcare perspective. The use of lactic acid bacteria (LAB) such as lactobacilli is an effective strategy for production and valorization of new BAPs. The proteolytic activity of lactobacilli is exerted in a strain-and species-dependent manner: each species exhibits different proteinase content, leading to a large variety of proteolytic activities. This underlines the high potential of Lactobacillus strains to produce novel hydrolysates and BAPs of major interest. This review aims at discussing the potential of different Lactobacillus species to release BAPs from fermentation media and processes. Strategies used for peptide production are presented. Additionally, we propose a methodology to select the most promising Lactobacillus strains as sources of BAPs. This methodology combines conventional approaches and in silico analyses.

Today, plant production is increasing, but most industrial processes generate a lot of waste and by-products for which, in the current context, it is a priority to recycle or valorize them. One of the cheapest valorization routes is fermentation, in particular lactic fermentation by Lactobacillus species, which produces lactic acid and other molecules of industrial interest such as bioactive compounds such as anthocyanin, organic acid, peptides, or phenol, which are widely found in the plant matrix, mainly in cereals, grass, fruits, and vegetables. Bioactive compounds may exert beneficial health effects, such as antioxidant, anti-inflammatory, antimicrobial, or prebiotic activities. In addition, lactic acid fermentation can improve existing products and lead to new applications in food, livestock feeding and biotechnology, such as the production of lactic acid, protein, or silage. This chapter reviews the use of Lactobacillus strains in the fermentation process of many plant bioresources or by-products through their different bioactivities, active molecules, and applications.