CERELA   05438
CENTRO DE REFERENCIA PARA LACTOBACILOS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Study of folate production by wild-type strains of lactic acid bacteria for elaboration of novel bio-enriched foods
Autor/es:
LAIÑO, JONATHAN; LEBLANC, JEAN GUY; SAVOY, GRACIELA
Lugar:
San Miguel de Tucumán
Reunión:
Congreso; VII Congreso Argentino de Microbiología General SAMIGE del Bicentenario; 2011
Institución organizadora:
Sociedad Argentina de Microbiología General SAMIGE
Resumen:
Folate, an essential B-group vitamin, is involved in many metabolic pathways such as energy usage and DNA and RNA biosynthesis. Human beings cannot synthesize folate so an exogenous supply of this vitamin is necessary to prevent nutritional deficiency. Extensive researches have shown that many health benefits are associated with increased folic acid intakes. However, numerous studies have put into evidence that high intakes of this synthetic form of folate can cause adverse effects in some individuals such as the masking of the hematological alterations of vitamin B12 deficiency. This does not occur with natural folates present in foods or produced by microorganisms. Currently, many researchers are evaluating novel strategies to increase concentrations of naturally occurring folate in foods. The proper selection and use of folate producing lactic acid bacteria (LAB) is an interesting alternative to increase “natural” folate levels in foods. Aim: To find and select wild-type LAB able to produce folate and study its production. Screening of 43 strains of Lactobacillus (Lb.) bulgaricus and 52 Streptococcus (St.) thermophilus was performed and different parameters were evaluated such as: a) growth in absence and presence of folate vitamin in a deficient medium; b) total concentration of folate; c) concentration of secreted and intracellular folate d) pH of the folate-free medium, e) absorbance at 580 nm and f) UFC/ml of the selected folate producing strains. Folate concentrations were performed using a Lb. rhamnosus NCIMB 10463 microbiological assay. Results: from the 95 analyzed LAB only 37 strains (5 Lb. bulgaricus and 32 St. thermophilus) grew in absence of folates producing varying amounts of folates (between 19.27±0.12 to 144.36±0.10 µg/l). In these 37 strains, only 2 Lb. bulgaricus secreted significant amounts of folates (>80.0±0.1µg/l) and 11 St. thermophilus showed the highest intracellular vitamin concentration (>15.0±0.1µg/l). From these results, four LAB (2 Lb. bulgaricus and 2 St. thermophilus) were selected for future studies. Conclusion: native strains of LAB were able to produce significant amounts of folate and it was shown that the vitamin production was not directly associated to microbial growth. The selected strains could be used in the elaboration of novel bio-enriched fermented products.