In vitro and in vivo survival and colonic adhesion of Pediococcus acidilactici MTCC5101 in human gut.

The present study aims to investigate the probiotic nature of Pediococcus acidilactici MTCC5101 by an in vitro assay of bacterial adherence to intestinal epithelial cells of human gastrointestinal (GI) tract using Caco-2 cell line. Further to assess the in vivo survival in the GI tract, oral feeding was carried out with the help of 10 healthy volunteers. The effect on wellness was assessed by studying blood biochemical parameters of the volunteers. The survival of the bacteria was assessed using PCR-based detection of P. acidilactici MTCC5101 in fecal samples. The probiotic nature of P. acidilactici MTCC 5101 was strengthened by its adherence to the intestinal epithelial Caco-2 cell line in the in vitro SEM observations. Oral feeding study for assessing the survival of bacteria in GI tract of volunteers showed the strain to be established in the GI tract which survived for about 2 weeks after feeding.

Naturally occurring 2-substituted (1,3)-beta-D-glucan producing Lactobacillus suebicus and Pediococcus parvulus strains with potential utility in the production of functional foods.

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.

Reclassification of Pediococcus urinaeequi (ex Mees 1934) Garvie 1988 as Aerococcus urinaeequi comb. nov.

The taxonomic status of Pediococcus urinaeequi is described, and the transfer of the species to the genus Aerococcus with the name Aerococcus urinaeequi comb. nov. is proposed, on the basis of the analysis of 16S rRNA gene sequence and DNA-DNA hybridization data.

Selective antimicrobial activity of chitosan on beer spoilage bacteria and brewing yeasts.

Chitosan (0.1 g l(-1)), assayed in a simple medium, reduced the viability of four lactic acid bacteria isolated during the beer production process by 5 logarithmic cycles, whereas activity against seven commercial brewing yeasts required up to 1 g chitosan l(-1). Antimicrobial activity was inversely affected by the pH of the assay medium. In brewery wort, chitosan (0.1 g l(-1)) selectively inhibited bacterial growth without altering yeast viability or fermenting performance.

Optimization of the culture medium for growth and the kinetics of lactate fermentation by Pediococcus sp. ISK-1.

The growth of a newly isolated strain of Pediococcus sp., designated ISK-1, was very slow and the concentration of cells in the medium remained low. Fermentation with an initial 30 g/liter glucose required about 60 h. To stimulate fermentation, we attempted to optimize the medium by flask culture and jar fermentation tests. Mevalonic acid and mieki (soy bean hydrolyzate) stimulated fermentation and increased the rate of formation of DL-lactate. Kinetic analysis of the fermentation showed that mevalonic acid markedly increased the specific glucose consumption rate and the specific lactate production rate. Mieki and mevalonic acid had a synergistic effect, but the effect of mevalonic acid was different from that of mieki.