Recent update on lactic acid bacteria producing riboflavin and folates: application for food fortification and treatment of intestinal inflammation.

Lactic acid bacteria (LAB), widely used as starter cultures for the fermentation of a large variety of food, can improve the safety, shelf life, nutritional value and overall quality of the fermented products. In this regard, the selection of strains delivering health-promoting compounds is now the main objective of many researchers. Although most LAB are auxotrophic for several vitamins, it is known that certain strains have the capability to synthesize B-group vitamins. This is an important property since humans cannot synthesize most vitamins, and these could be obtained by consuming LAB fermented foods. This review discusses the use of LAB as an alternative to fortification by the chemical synthesis to increase riboflavin and folate concentrations in food. Moreover, it provides an overview of the recent applications of vitamin-producing LAB with anti-inflammatory/antioxidant activities against gastrointestinal tract inflammation. This review shows the potential uses of riboflavin and folates producing LAB for the biofortification of food, as therapeutics against intestinal pathologies and to complement anti-inflammatory/anti-neoplastic treatments.

Evaluation of vitamin-producing and immunomodulatory lactic acid bacteria as a potential co-adjuvant for cancer therapy in a mouse model.

AIMS: To evaluate a mixture of selected lactic acid bacteria (LAB) (a riboflavin-producer, a folate-producer and an immunomodulatory strain) as co-adjuvant for 5-fluorouracil (5-FU) chemotherapy in cell culture and using a 4T1 cell animal model of breast cancer. METHODS AND RESULTS: The viability of Caco-2 cells exposed to 5-FU and/or LAB was analysed. Mice bearing breast tumour were treated with 5-FU and/or LAB. Tumour growth was measured. Intestinal mucositis (IM) was evaluated in small intestine; haematological parameters and plasma cytokines were determined. The bacterial mixture did not negatively affect the cytotoxic activity of 5-FU on Caco-2 cells. The LAB mixture attenuated the IM and prevented blood cell decreases associated with 5-FU treatment. Mice that received 5-FU and LAB mixture decreased tumour growth and showed modulation of systemic cytokines modified by both tumour growth and 5-FU treatment. The LAB mixture by itself delayed tumour growth. CONCLUSIONS: The mixture of selected LAB was able to reduce the side-effects associated with chemotherapy without affecting its primary anti-tumour activity. SIGNIFICANCE AND IMPACT OF THE STUDY: This bacterial mixture could prevent the interruption of conventional oncologic therapies by reducing undesirable side-effects. In addition, this blend would provide essential nutrients (vitamins) to oncology patients.

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

AIM: To evaluate two folate-producing strains, Streptococcus (Strep.) thermophilus CRL 808 and Strep. thermophilus CRL 415, against chemically induced mucositis in mice. METHODS AND RESULTS: In vitro assays with Caco-2 cells were performed to evaluate the effect of the bacteria in the presence of 5-fluorouracil (5-FU). For in vivo studies, mice were daily injected with 5-FU to induce intestinal mucositis (IM) and orally administered with folate-producing strains during 6 days. Clinical symptoms, histological parameters and cytokine profiles were assessed. The results showed that Strep. thermophilus CRL 808 increased the cytotoxicity of 5-FU against Caco-2 cells. Administration of this strain in mice with chemically induced IM resulted in a reduction in diarrhoea score and restoration of the intestinal architecture. Cytokine analysis showed that the anti-inflammatory effect by the bacterium is not associated with an immune mechanism. Regarding Strep. thermophilus CRL 415, no improvements were observed in any of the parameters evaluated. CONCLUSION: The administration of the folate-producing Strep. thermophilus CRL 808 has the potential to prevent IM induced by 5-FU in mice. SIGNIFICANCE AND IMPACT OF THE STUDY: Folate-producing LAB could be used in chemotherapy patients to reduce the symptoms of IM, improve their nutritional status and increase the effectiveness of 5-FU.

Effect of riboflavin-producing bacteria against chemically induced colitis in mice.

AIM: To assess the anti-inflammatory effect associated with individual probiotic suspensions of riboflavin-producing lactic acid bacteria (LAB) in a colitis murine model. METHODS AND RESULTS: Mice intrarectally inoculated with trinitrobenzene sulfonic acid (TNBS) were orally administered with individual suspensions of riboflavin-producing strains: Lactobacillus (Lact.) plantarum CRL2130, Lact. paracasei CRL76, Lact. bulgaricus CRL871 and Streptococcus thermophilus CRL803; and a nonriboflavin-producing strain or commercial riboflavin. The extent of colonic damage and inflammation and microbial translocation to liver were evaluated. iNOs enzyme was analysed in the intestinal tissues and cytokine concentrations in the intestinal fluids. Animals given either one of the four riboflavin-producing strains showed lower macroscopic and histologic damage scores, lower microbial translocation to liver, significant decreases of iNOs+ cells in their large intestines and decreased proinflammatory cytokines, compared with mice without treatment. The administration of pure riboflavin showed similar benefits. Lact. paracasei CRL76 accompanied its anti-inflammatory effect with increased IL-10 levels demonstrating other beneficial properties in addition to the vitamin production. CONCLUSION: Administration of riboflavin-producing strains prevented the intestinal damage induced by TNBS in mice. SIGNIFICANCE AND IMPACT OF THE STUDY: Riboflavin-producing phenotype in LAB represents a potent tool to select them for preventing/treating IBD.

Soyamilk fermented with riboflavin-producing Lactobacillus plantarum CRL 2130 reverts and prevents ariboflavinosis in murine models.

It has been previously shown that Lactobacillus plantarum CRL 2130 is able to produce riboflavin in soyamilk. The aim of the present study was to evaluate the efficiency of this riboflavin-bio-enriched soyamilk to revert and/or prevent the nutritional deficiency of riboflavin using different animal models. When used to supplement the diets of previously depleted animals, it was shown that the growth, riboflavin status and morphology of the small intestines reverted to normal parameters and were similar to animals supplemented with commercial riboflavin. In the prevention model, the same tendency was observed, where animals that received soyamilk fermented with L. plantarum CRL 2130 did not show signs of riboflavin deficiency. This new bio-fortified soya-based product could be used as part of normal diets to provide a more natural alternative to mandatory fortification with riboflavin for the prevention of its deficiency.

ß-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 ß-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 ß-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 ß-casein hydrolysate was evaluated using a trinitrobenzene sulfonic acid (TNBS)-induced Crohn's disease murine model. The hydrolysate was administered to mice 10 d before the intrarectal inoculation of TNBS. The mice that received ß-casein hydrolysate previously to TNBS showed decreased mortality rates, faster recovery of initial body weight loss, less microbial translocation to the liver, decreased ß-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, ß-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 alpha-galactosidase from Lactobacillus fermentum CRL722: genetic characterization and main properties.

Alpha-galactosidase (alpha-Gal) enzyme, which is encoded by the melA gene hydrolyzes alpha-1,6 galactoside linkages found in sugars, such as raffinose and stachyose. These alpha-galacto-oligosaccharides (alpha-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 alpha-Gal in the gut. The use of microbial alpha-Gal is a promising alternative to eliminate alpha-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 alpha-Gal gene of thermophilic microorganisms. The alpha-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 degrees C) and stable at wide ranges of temperatures and pH. The thermostable alpha-Gal from L. fermentum CRL722 could thus be used for technological applications, such as the removal of alpha-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 alpha-GOS in situ. Both strategies would improve the overall acceptability of soy-derived products by improving their nutritional value.

Ingestion of milk fermented by genetically modified Lactococcus lactis improves the riboflavin status of deficient rats.

Riboflavin deficiency is common in many parts of the world, particularly in developing countries. The use of riboflavin-producing strains in the production of dairy products such as fermented milks, yogurts, and cheeses is feasible and economically attractive because it would decrease the costs involved during conventional vitamin fortification and satisfy consumer demands for healthier foods. The present study was conducted to assess in a rat bioassay the response of administration of milk fermented by modified Lactococcus lactis on the riboflavin status of deficient rats. Rats were fed a riboflavin-deficient diet during 21 d after which this same diet was supplemented with milk fermented by Lactoccus lactis pNZGBAH, a strain that overproduces riboflavin during fermentation. The novel fermented product, with increased levels of riboflavin, was able to eliminate most physiological manifestations of ariboflavinosis, such as stunted growth, elevated erythrocyte glutathione reductase activation coefficient values and hepatomegaly, that were observed using a riboflavin depletion-repletion model, whereas a product fermented with a nonriboflavin-producing strain did not show similar results. A safety assessment of this modified strain was performed by feeding rodents with the modified strain daily for 4 wk. This strain caused no detectable secondary effects. These results pave the way for analyzing the effect of similar riboflavin-overproducing lactic acid bacteria in human trials. The regular consumption of products with increased levels of riboflavin could help prevent deficiencies of this essential vitamin.

Reduction of alpha-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 alpha-galactooligosaccharides (alpha-GOS) because mammals lack pancreatic alpha-galactosidase (alpha-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 alpha-Gal is a promising solution for the degradation of alpha-GOS in soyamilk. METHODS AND RESULTS: The capacity of the LAB Lactobacillus fermentum CRL 722 to properly degrade alpha-GOS was studied in vitro using controlled fermentation conditions and in vivo using a rat model. Lactobacillus fermentum CRL 722 was able to grow on commercial soyamilk and completely eliminated stachyose and raffinose during fermentation because of its high alpha-Gal activity. Rats fed soyamilk fermented by this LAB had smaller caecums compared with rats fed unfermented soyamilk. CONCLUSIONS: Soyamilk fermentation by Lact. fermentum CRL 722 results in the reduction of alpha-GOS concentrations in soyamilk, thus eliminating possible undesirable physiological effects normally associated with its consumption. SIGNIFICANCE AND IMPACT OF THE STUDY: Fermentation with Lact. fermentum CRL 722 could prevent gastrointestinal disorders in sensitive individuals normally associated with the consumption of soya-based products. This LAB could thus be used in the elaboration of novel fermented vegetable products which better suit the digestive capacities of consumers.

Effect of pH on Lactobacillus fermentum growth, raffinose removal, alpha-galactosidase activity and fermentation products.

In this study, the behaviour of Lactobacillus fermentum CRL 722 and CRL 251 were evaluated under different pH conditions (pH 6.0, 5.5, 5.0, 4.5) and without pH control. Growth was similar under all conditions assayed except at pH 4.5. These microorganisms were able to eliminate raffinose, a nondigestible alpha-oligosaccharide (NDO) found in soy products, showing a consumption rate of 0.25 g l(-1) h(-1) (pH 6.0-5.0). The removal of raffinose was due to the high alpha-galactosidase (alpha-gal) activities of these lactic acid bacteria, which was highest at pH 5.5 (5.0 U/ml). The yield of organic acids produced during raffinose consumption was also highest at this pH. The results of this study will allow selection of the optimum growth conditions of L. fermentum with elevated levels of alpha-gal to be used in the reduction of NDO in soy products when used as starter cultures.

UDP-galactose 4-epimerase: a key enzyme in exopolysaccharide formation by Lactobacillus casei CRL 87 in controlled pH batch cultures.

AIMS: To evaluate the relationship between exopolysaccharide (EPS) production and the sugar nucleotide biosynthetic enzymes in Lactobacillus casei CRL 87 under optimum growth conditions for polymer formation: controlled pH on galactose or glucose. Studies with an EPS mutant were carried out to determine the key enzymes in EPS synthesis under the above culture conditions. METHODS AND RESULTS: EPS concentration was estimated by the phenol/sulphuric acid method, while the activities of the biosynthetic enzymes were determined spectrophotometrically by measuring the formation or disappearance of NAD(P)H at 340 nm. An environmental pH of 5.0, using galactose as carbon source, markedly improved not only polymer production and yield but also, cell growth and lactic acid production. Analysis of the activities of the EPS precursor-forming enzymes revealed that polysaccharide synthesis was correlated with uridine-diphosphate (UDP)-glucose pyrophosphorylase and UDP-galactose 4-epimerase under these growth conditions. CONCLUSIONS: EPS synthesis by Lact. casei CRL 87 was considerably improved at a controlled pH of 5.0 with galactose as carbon source, and was correlated with the activity of UDP-glucose pyrophosphorylase and UDP-galactose 4-epimerase. The results obtained with the wild-type and EPS- strains suggest that UDP-galactose 4-epimerase plays an essential role in EPS formation. SIGNIFICANCE AND IMPACT OF THE STUDY: Unravelling the key enzymes involved in EPS biosynthesis under optimum culture conditions for polymer production provides important information for the design of strategies, via genetic engineering, to enhance polysaccharide formation.

Comparative study of the efficiency of some additives in protecting lactic acid bacteria against freeze-drying.

Cultures of 14 lactic acid bacteria species were freeze-dried in 10 or 20% non-fat skim milk and in distilled water containing one of the following additives: bovine albumin, glycogen, dextran, polyethylene glycol (PEG) 1000, PEG 4000, PEG 6000, glycerol, beta-glycerophosphate, sodium glutamate, asparagine, or cysteine. Each of the potential protective agents tested exhibited marked variations in the protection afforded to different species, none of them was effective for the preservation of viability of thermophilic lactobacilli. However, glycerol provided effective protection for L. leichmannii ATCC 4797 (90% survival), while L. bulgaricus ATCC 11842 reached a viability of 78% with 0.04 M cysteine.

Isolation and identification of anaerobic contaminants from a machine for producing processed cheese.

Some bacteria of the genus Clostridium can contaminate milk. These bacteria can cause "the late gas" or "late blowing" defect in the cheese if this is made with milk containing such contaminants. In this study, six samples from a processed cheese contaminated in a manufacturing machine were analysed. Out of 60 strains studied, 30 were classified as Clostridium tyrobutyricum, 20 as Clostridium butyricum, and 10 as Desulfotomaculum ruminis.

Isolation and identification of anaerobic contaminants from a machine for producing processed cheese.

Some bacteria of the genus Clostridium can contaminate milk. These bacteria can cause [quot ]the late gas[quot ] or [quot ]late blowing[quot ] defect in the cheese if this is made with milk containing such contaminants. In this study, six samples from a processed cheese contaminated in a manufacturing machine were analysed. Out of 60 strains studied, 30 were classified as Clostridium tyrobutyricum, 20 as Clostridium butyricum, and 10 as Desulfotomaculum ruminis.

Isolation and identification of anaerobic contaminants from a machine for producing processed cheese.

Sesenta cepas fueron seleccionadas a partir de seis muestras de queso fundido y tres cultivos de material contaminado de la maquina procesadora. Todos los microorganismos aislados fueron bacilos catalasa (-), anaerobicos estrictos y esporulados con esporas subterminales. El 83% de las cepas fueron Gram (+) correspondiendo al Genero III Clostridium. Un estudio posterior permitio clasificarlas como Clostridium butyricum y Clostridium tyrobutyricum. Las veinte cepas restantes fueron Gram (-). Por su capacidad de reducir su fito se las ubico en el Genero IV Desulfotomaculum

Isolation and identification of anaerobic contaminants from a machine for producing processed cheese.

Sesenta cepas fueron seleccionadas a partir de seis muestras de queso fundido y tres cultivos de material contaminado de la maquina procesadora. Todos los microorganismos aislados fueron bacilos catalasa (-), anaerobicos estrictos y esporulados con esporas subterminales. El 83% de las cepas fueron Gram (+) correspondiendo al Genero III Clostridium. Un estudio posterior permitio clasificarlas como Clostridium butyricum y Clostridium tyrobutyricum. Las veinte cepas restantes fueron Gram (-). Por su capacidad de reducir su fito se las ubico en el Genero IV Desulfotomaculum