CONICET | Buscador de Institutos y Recursos Humanos

Feruloyl esterases (FE) are enzymes that hydrolyze hydroxycinnamate esters naturally present in vegetable foods, releasing hydroxycinnamic acids (HA) that can be absorbed at the gut. HA, such as ferulic acid (FA), have antioxidant properties in vitro and in vivo. Thus, the use of lactic acid bacteria with FE activity represents an innovative proposal in the field of functional foods and dietary supplements. Our aim was to evaluate the effect of different carbon sources on growth and FE activity of probiotic lactobacilli strains. Three FE producing-strains of food and intestinal origin were used: Lactobacillus fermentum (Lf) CRL1446, L. johnsonii (Lj) CRL1231 and L. acidophilus (La) CRL1014. Cell growth (O.D. 560 nm) in a minimal culture medium supplemented with different carbon sources (0.5% w/v glucose, xylose, arabinose, fructose, ethyl ferulate, chlorogenic acid) was evaluated. Minimal medium without supplementation was used as control. FE activity was determined by incubation of cell suspensions (obtained from 6 h cultures) in PBS pH 7 containing 1 mM methyl ferulate as substrate. Released FA was quantified by HPLC. All strains grew in the different media assayed, remaining in exponential phase until 6 h. In general, the highest growth rates were observed in media containing glucose and fructose. Compared to control, no differences were detected in presence of hydroxycinnamates (ethyl ferulate or chlorogenic acid). FE activity of Lf and Lj was induced by ethyl ferulate (10% and 80%, respectively), whereas in La it was stimulated by chlorogenic acid (37%). Regarding the effect of monosaccharides on FE activity, induction by glucose in Lf and by xylose in La was observed (19% and 15%, respectively). Results show that FE activity is mainly induced by hydroxycinnamates, indicating that the evaluated strains could be used in functional foods naturally rich in these compounds, contributing to an increased bioavailability of HA.

enviar mensaje