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In order to purify proteinase fromLactobacillus delbrueckiisubsp.bulgaricus, chromatography methods including ion-exchange and hydrophobic interaction were combined. Chromatographic conditions were structured and optimized. The final sample volume, flow rate, and length of gradient for anion exchange chromatography were 20 mL, 5 mL/min and 10 column volume length of gradient, in that order. Besides, the flow rate and length of gradient for hydrophobic interaction chromatography were 1 mL/min and 10 column volume. Proteinase was purified up to 43-fold with a specific activity of 54.4 U/mg protein, and the recovery of 46.6%. The molecular weight of the purified proteinase was about 40 kDa. [ABSTRACT FROM PUBLISHER]

The survival of bifidobacteria in simulated conditions of the gastrointestinal (GI) tract was studied based on the D- and z-value concept. Some Bifidobacterium spp. are probiotics that improve microbial balance in the human GI tract. Because they are sensitive to low pH and bile salt concentrations, their viability in the GI tract is limited. The D- and z-value approach was therefore adopted as a result of observing constant log-cell reduction (90%) when Bifidobacterium spp. were exposed to these 2 different stressing factors. Survivals of one strain each or 4 species of Bifidobacterium was studied at pH between 3.0 and 4.5 and in ox-bile between 0.15% and 0.60% for times up to 41 h. From the Dacid- and Dbile-values, the order of resistance to acid and bile was B. bifidum > B. infantis > B. longum > B. adolescentis. While the former 3 strains retained high cell viability at pH 3.5 (>5.5 log CFU/mL after 5 h) and at elevated bile salt concentration of 0.6% (>4.5 log CFU/mL after 3 h), B. adolescentis was less resistant (<3.4 log CFU/mL). The zacid- and zbile-values calculated from the Dacid- and Dbile-values ranged from 1.11 to 1.55 pH units and 0.40% to 0.49%, respectively. The results suggest that the Dacid-, Dbile-, zacid-, and zbile-value approach could be more appropriate than the screening and selection method in evaluating survival of probiotic bacteria, and in measuring their tolerance or resistance to gastric acidity and the associated bile salt concentration in the small intestine. Practical Application: The evaluation of the tolerance of bifidobacteria to bile salts and low pH has been made possible by use of D- and z-value concept. The calculated zacid- and zbile-values were all fairly similar for the strains used and suggest the effect of increasing the bile salt concentration or decreasing the pH on the Dacid- and Dbile-values. This approach would be useful for predicting the suitability of bifidobacteria and other lactic acid bacteria (LAB) as probiotics for use in real-life situations. [ABSTRACT FROM AUTHOR]

Abstract: Actual textile wastewater and synthesized wastewater containing various textile dyes were photocatalytic degraded by the UVH2O2FS-TiO2 process in an annular-flow photocatalytic reactor. In this process, a photon kinetic-measure was adopted to obtain constant rates of dyes decomposition. It was theorized that, by illumination at different UV frequencies, the electrons within the semiconductor were excited from the valence band to the conduction band, yielding the formation of electron-hole pairs which are the pre-requisites for photocatalysis. CPT (critical photonic time) exposure required to cause 90% of vibrations between the double and single bonds along the molecular chain of the dyes to be oxidized, was taken to measure the photocatalytic activities. The CPTs varied with the frequencies of the UV spectral areas. The derivatization of CPT from the first-order kinetic law was presented. [Copyright &y& Elsevier]

Unlabelled: The survival of bifidobacteria in simulated conditions of the gastrointestinal (GI) tract was studied based on the D- and z-value concept. Some Bifidobacterium spp. are probiotics that improve microbial balance in the human GI tract. Because they are sensitive to low pH and bile salt concentrations, their viability in the GI tract is limited. The D- and z-value approach was therefore adopted as a result of observing constant log-cell reduction (90%) when Bifidobacterium spp. were exposed to these 2 different stressing factors. Survivals of one strain each or 4 species of Bifidobacterium was studied at pH between 3.0 and 4.5 and in ox-bile between 0.15% and 0.60% for times up to 41 h. From the D(acid)- and D(bile)-values, the order of resistance to acid and bile was B. bifidum > B. infantis > B. longum > B. adolescentis. While the former 3 strains retained high cell viability at pH 3.5 (>5.5 log CFU/mL after 5 h) and at elevated bile salt concentration of 0.6% (>4.5 log CFU/mL after 3 h), B. adolescentis was less resistant (<3.4 log CFU/mL). The z(acid)- and z(bile)-values calculated from the D(acid)- and D(bile)-values ranged from 1.11 to 1.55 pH units and 0.40% to 0.49%, respectively. The results suggest that the D(acid)-, D(bile)-, z(acid)-, and z(bile)-value approach could be more appropriate than the screening and selection method in evaluating survival of probiotic bacteria, and in measuring their tolerance or resistance to gastric acidity and the associated bile salt concentration in the small intestine., Practical Application: The evaluation of the tolerance of bifidobacteria to bile salts and low pH has been made possible by use of D- and z-value concept. The calculated z(acid)- and z(bile)-values were all fairly similar for the strains used and suggest the effect of increasing the bile salt concentration or decreasing the pH on the D(acid)- and D(bile)-values. This approach would be useful for predicting the suitability of bifidobacteria and other lactic acid bacteria (LAB) as probiotics for use in real-life situations.