The gastrointestinal transit tolerance of Lactobacillus plantarum strain No. 14 depended on the carbon source.

This study aimed to assess variations in the human gastrointestinal transit tolerance of Lactobacillus plantarum strain No. 14 after culture with glucose and with fructose. Transit tolerance was determined at 37 degrees C against simulated gastric juices at pH values of 2.5, 3.0, and 3.5, and against simulated small intestinal juices containing 0%, 0.2%, or 0.4% oxgall. The simulated gastrointestinal transit tolerance of Lactobacillus plantarum strain No. 14 varied with the carbon source. Hence we compared the amounts of exopolysaccharide from Lactobacillus plantarum strain No. 14 cultured in various carbon sources. The exopolysaccharide levels were 146.5+/-8.1 mg/l (culture) with glucose, and 20.1+/-17.0 mg/l (culture) with fructose. When exopolysaccharide was removed by centrifugation, the simulated gastric tolerance of Lactobacillus plantarum strain No. 14 cultured with glucose decreased markedly, but that with fructose did not decrease. These results suggest that the gastrointestinal transit tolerance of Lactobacillus plantarum strain No. 14 is related to exopolysaccharide contents.

Effects of minerals on resistance of Bacillus subtilis spores to heat and hydrostatic pressure.

Among Bacillus subtilis IFO13722 spores sporulated at 30, 37, and 44 degrees C, those sporulated at 30 degrees C had the highest resistance to treatments with high hydrostatic pressure (100 to 300 MPa, 55 degrees C, 30 min). Pressure resistance increased after demineralization of the spores and decreased after remineralization of the spores with Ca(2+) or Mg(2+), whereas the resistance did not change when spores were remineralized with Mn(2+) or K(+), suggesting that former two divalent ions were involved in the activation of cortex-lytic enzymes during germination.