G. Savoy de Giori

B-group vitamin production by lactic acid bacteria--current knowledge and potential applications.

Although most vitamins are present in a variety of foods, human vitamin deficiencies still occur in many countries, mainly because of malnutrition not only as a result of insufficient food intake but also because of unbalanced diets. Even though most lactic acid bacteria (LAB) are auxotrophic for several vitamins, it is now known that certain strains have the capability to synthesize water‐soluble vitamins such as those included in the B‐group (folates, riboflavin and vitamin B12 amongst others). This review article will show the current knowledge of vitamin biosynthesis by LAB and show how the proper selection of starter cultures and probiotic strains could be useful in preventing clinical and subclinical vitamin deficiencies. Here, several examples will be presented where vitamin‐producing LAB led to the elaboration of novel fermented foods with increased and bioavailable vitamins. In addition, the use of genetic engineering strategies to increase vitamin production or to create novel vitamin‐producing strains will also be discussed. This review will show that the use of vitamin‐producing LAB could be a cost‐effective alternative to current vitamin fortification programmes and be useful in the elaboration of novel vitamin‐enriched products.

Effect of galactose and glucose on the exopolysaccharide production and the activities of biosynthetic enzymes in Lactobacillus casei CRL 87.

Aims: The objective of this work was to study the influence of the sugar source on exopolysaccharide (EPS) production and the activities of the enzymes involved in the synthesis of sugar nucleotides in Lactobacillus casei CRL 87. The relationship between these enzymes and EPS formation was determined.

β-Casein hydrolysate generated by the cell envelope-associated proteinase of Lactobacillus delbrueckii ssp. lactis CRL 581 protects against trinitrobenzene sulfonic acid-induced colitis in mice

Lactobacillus delbrueckii ssp. lactis CRL 581, a thermophilic lactic acid bacterium used as a starter culture for the manufacture of several fermented dairy products, possesses an efficient proteolytic system that is able to release a series of potentially bioactive peptides (i.e., antihypertensive and phosphopeptides) from α- and β-caseins. Considering the potential beneficial health effects of the peptides released by L. delbrueckii ssp. lactis CRL 581 from milk proteins, the aim of this work was to analyze the anti-mutagenic and anti-inflammatory properties of the casein hydrolysates generated by the cell envelope-associated proteinase of this bacterium. The ability of α- and β-casein hydrolysates to suppress the mutagenesis of a direct-acting mutagen 4-nitroquinoline-N-oxide on Salmonella typhimurium TA 98 and TA 100 increased concomitantly with the time of casein hydrolysis. The anti-inflammatory effect of the β-casein hydrolysate was evaluated using a trinitrobenzene sulfonic acid (TNBS)-induced Crohns disease murine model. The hydrolysate was administered to mice 10 d before the intrarectal inoculation of TNBS. The mice that received β-casein hydrolysate previously to TNBS showed decreased mortality rates, faster recovery of initial body weight loss, less microbial translocation to the liver, decreased β-glucuronidase and myeloperoxidase activities in the gut, and decreased colonic macroscopic and microscopic damage compared with the animals that did not receive this hydrolysate. In addition, β-casein hydrolysate exerted a beneficial effect on acute intestinal inflammation by increased interleukin 10 and decreased IFN-γ production in the gut. Our findings are consistent with the health-promoting attributes of the milk products fermented by L. delbrueckii ssp. lactis CRL 581 and open up new opportunities for developing novel functional foods.

A Thermostable α-Galactosidase from Lactobacillus fermentum CRL722: Genetic Characterization and Main Properties

Abstractα-Galactosidase (α-Gal) enzyme, which is encoded by the melA gene hydrolyzes α-1,6 galactoside linkages found in sugars, such as raffinose and stachyose. These α-galacto-oligosaccharides (α-GOS), which are found in large quantities in vegetables, such as soy, can cause gastrointestinal disorders in sensitive individuals because monogastric animals (including humans) do not posses α-Gal in the gut. The use of microbial α-Gal is a promising alternative to eliminate α-GOS in soy-derived products. Using degenerate primers, the melA gene from Lactobacillus (L.) fermentum CRL722 was identified. The complete genomic sequence of melA (2223 bp), and of the genes flanking melA, were obtained using a combination of polymerase chain reaction–based techniques, and showed strong similarities with the α-Gal gene of thermophilic microorganisms. The α-Gal gene from L. fermentum CRL722 was cloned and the protein purified from cell-free extracts of the native and recombinant strains using various techniques (ion exchange chromatography, salt precipitation, sodium dodecyl sulfate–polyacrylamide gel electrophoresis, and ultra-filtration); Its main biochemical properties were determined. The enzyme was active at moderately high temperatures (55°C) and stable at wide ranges of temperatures and pH. The thermostable α-Gal from L. fermentum CRL722 could thus be used for technological applications, such as the removal of α-GOS found in soy products. The complete melA gene could also be inserted in other micro-organisms, that can survive in the harsh conditions of the gut to degrade α-GOS in situ. Both strategies would improve the overall acceptability of soy-derived products by improving their nutritional value.

Reduction of α‐galactooligosaccharides in soyamilk by Lactobacillus fermentum CRL 722: in vitro and in vivo evaluation of fermented soyamilk

Aims:  Consumption of soya‐derived products has been hampered by the presence of α‐galactooligosaccharides (α‐GOS) because mammals lack pancreatic α‐galactosidase (α‐Gal) which is necessary for their hydrolysis. These sugars thus reach the large intestine causing gastrointestinal disorders in sensitive individuals. The use of lactic acid bacteria (LAB) expressing α‐Gal is a promising solution for the degradation of α‐GOS in soyamilk.

Evaluation of the effect of soymilk fermented by a riboflavin-producing Lactobacillus plantarum strain in a murine model of colitis

Inflammatory bowel diseases (IBD) are idiopathic diseases of the gastrointestinal tract characterised by recurrent inflammation that require lifelong treatments. It has been shown that certain strains of lactic acid bacteria (LAB) can produce specific health-promoting compounds in foods or in the gastrointestinal tract that can in turn prevent and/or treat IBD. This study was designed to evaluate the possible therapeutic potential of soymilk fermented by the riboflavin-producing strain Lactobacillus plantarum CRL 2130 in a trinitrobenzene sulfonic induced colitis mouse model. Mice that received soymilk fermented by L. plantarum CRL 2130 showed a decrease in weight loss, lower damage scores in their large intestines, lower microbial translocation to liver and decreased cytokines levels in their intestinal fluids compared to animals that received unfermented soymilk or soymilk fermented by a non-riboflavin-producing L. plantarum strain. This is the first report that demonstrates that a riboflavin-producing LAB was able to prevent experimental colitis in a murine model.

Folate-producing lactic acid bacteria reduce inflammation in mice with induced intestinal mucositis

To evaluate two folate‐producing strains, Streptococcus (Strep.) thermophilus CRL 808 and Strep. thermophilus CRL 415, against chemically induced mucositis in mice.

Draft Genome Sequence of Lactobacillus rhamnosus CRL1505, an Immunobiotic Strain Used in Social Food Programs in Argentina

ABSTRACT We report the draft genome sequence of the probiotic Lactobacillus rhamnosus strain CRL1505. This new probiotic strain has been included into official Nutritional Programs in Argentina. The draft genome sequence is composed of 3,417,633 bp with 3,327 coding sequences.