Development of Selenized Lactic Acid Bacteria and their Selenium Bioaccummulation Capacity

Abstract

Selenized lactic acid bacteria (LAB) represent potentially safe and effective sources of selenium (Se), essential for human health, as lactic acid fermentation improves Se bioavailability and reduces its toxicity. LAB are generally recognized as safe (GRAS) and widely used in fermented dairy products. To facilitate selenized LAB implementation as a functional food, we developed and characterized new Se-enriched strains based on the food industry commercial strains Streptococcus thermophilus CCDM 144 and Enterococcus faecium CCDM 922A as representatives of two LAB genera. We evaluated Se bioaccumulation capacity, Se biotransformation and growth ability in the presence of different sodium selenite concentrations (0–50 mg/L), and antioxidant properties (2, 2-diphenyl-1-picrylhydrazyl (DPPH) method) and cell surface hydrophobicity between Se-enriched and parental strains in vitro. Sodium selenite addition did not negatively influence growth of either strain; thus, 50 mg/L was chosen as the optimal concentration based on strain accumulation capacity. Selenization improved the antioxidant properties of both strains and significantly increased their cell surface hydrophobicity (p < 0.05). To our knowledge, this represents the first report of Se-enriched strain hydrophobicity as well as the first on Se speciation in families Enterococcaceae and Streptococcaceae. Moreover, both tested strains demonstrated good potential for Se-enrichment, providing a foundation for further in vitro and in vivo studies to confirm the suitability of these Se-enriched strains for industrial applications.

Designated functional microcapsules loaded with green synthesis selenium nanorods and probiotics for enhancing stirred yogurt

“…Which, two genes SelA and SelD are located in the probiotic strains genome and involved in Se metabolism 62 , 63 . So, the helpful effect of nanoparticles delivered to the gut microbiota, aiming to reduce the pathogens, by eliminated the growth of harmful microbes and improved beneficial bacteria as probiotics 64 , 65 .…”

In Vivo Bioavailability of Selenium in Selenium-Enriched Streptococcus thermophilus and Enterococcus faecium in CD IGS Rats

“…In our previous study [ 22 ], we highlighted the abilities of S. thermophilus CCDM 144 and E. faecium CCDM 922A to accumulate up to 7.3 mg/g Se and 6.5 mg/g Se, respectively. Therefore, these strains were used for selenium enrichment of the SeST (group D) and SeEF (group F) diets in this study.…”

“…The selenium species were identified using ion-pair liquid chromatography (HPLC) coupled with ICP-MS, as described previously [ 22 ]. Briefly, reversed-phase column (Purospher ® STAR RP-8 endcapped, 250 × 4.6 mm, 5 µm, Merck, Germany) and the mobile phase consisting of 1.0-g/L sodium butane-1-sulfonate, 0.22-g/L tetramethylammonium hydroxide pentahydrate, 0.42-g/L malonic acid, and 0.05% ( v / v ) methanol (Sigma Aldrich, Steinheim, Germany) were used for Se species separation.…”

“…In our previous study [ 22 ], an in vitro assessment of the properties of the selenized LAB strains Streptococcus thermophilus CCDM 144 and Enterococcus faecium CCDM 922A revealed that both strains could tolerate sodium selenite and accumulate, as well as biotransform Se into its organic form. These strains were further studied for their beneficial properties and potential to improve the host health.…”

Microbial Resources, Fermentation and Reduction of Negative Externalities in Food Systems: Patterns toward Sustainability and Resilience

“…Another group of bio-based innovations oriented at 'label cleaning', conceive alternatives to chemical preservatives [52][53][54] and to fortification via the addition of exogenous nutrients [55][56][57]. Some studies proposed pathways towards enhanced nutrient bioavailability [10,[58][59][60] and improved human health/well-being [61][62][63][64] (including microbiome therapies [63][64][65][66]), advances of interest to contrast the adverse effects of some negative externalities. Furthermore, the design of several works looking at reducing resource dissipation, saving energy [52,69], valorising foods by-products [52,70,71], foods wastes [72][73][74], and wastewater [75][76][77].…”