Search

We have isolated three lactic acid bacteria (Lactobacillus suebicus CUPV221, Pediococcus parvulus CUPV1 and P. parvulus CUPV22) that produced high levels of 2-substituted (1,3)-beta-D-glucans which increased the viscosity of the growth media. The (1,3)-beta-D-glucan consisted of two main molecular species, with masses of approximately 10(7) and 10(4) Da, whose proportions varied among the strains. The three strains survived exposure to saliva and simulated gastric conditions at pH 5, with P. parvulus CUPV22 surviving at pH 3.1, and L. suebicus CUPV221 surviving at pH 1.8. All strains were resistant to pancreatin and bile salts. P. parvulus CUPV22 exhibited the highest adhesion (10.5%) to Caco-2 cells, which decreased to 1.2% after washing the cells. Finally, P. parvulus CUPV22 and L. suebicus CUPV221 induced the production of inflammation-related cytokines by polarized macrophages, and interestingly, L. suebicus stimulated the production of cytokine IL-10. These results indicate that the three strains have potential utility for the production of functional foods., (2010 Elsevier Ltd. All rights reserved.)

The ability to produce a 2-branched (1,3)-beta-D-glucan was screened in 147 lactic acid bacteria strains recovered from cider. Among them, 32 identified as Pediococcus parvulus exhibited a ropy character and were PCR positive for the presence of the gtf gene, related to the synthesis of the beta-glucan. Half of the strains produced more than 100 mg L(-1) of exopolysaccharide (EPS). (1)H NMR spectra of the crude EPSs were identical to that previously described for P. parvulus 2.6, indicating that all are 2-branched (1,3)-beta-D-glucans. The EPSs from two of the isolates were subjected to acid hydrolysis and methylation analysis, confirming the NMR results. Size exclusion chromatography (SEC) showed in all crude EPSs the presence of two different molecular mass fractions of about 10(7) Da and 10(4) Da, whose relative proportions varied among strains. EPS amounts and concentrations of high molecular fraction are linearly correlated. Intraspecific diversity of isolates was determined by RAPD profiles. Based on genotypic and phenotypic characteristics, two strains were selected to be further studied as probiotics.