Isolation of lactobaciulus
- Principles of the Procedure Oxbile is used as a selective agent for the isolation of Gram-negative microorganisms, inhibiting Gram-positive bacteria.
The major composition of Oxbile is taurocholic and glycocholic acids.
Bromocresol purple (BCP) or 5',5"-dibromo-o-cresolsulfophthalein, is a pH indicator. In its sultone form, it has a pKa value of 6.3, and is usually prepared as a 0.04% aqueous solution. Bromocresol purple (pH indicator) below pH 5.2 above pH 6.8 5.2 ⇌ 6.8 Uses
Besides its primary function as an indicator, bromocresol purple is used in medical laboratories to measure albumin, and as an addition to acid stop baths used in photographic processing as an indicator that the bath has reached neutral pH and needs to be replaced.
The swabs were inoculated onto MRS agar plates (Difco) and incubated at 37°C with partial CO2 tension for 48 h. Growth on MRS was observed for 21 of the 105 analysed samples, and one or more colonies were selected and picked for each of the 21 samples. All colonies were examined by Gram staining and catalase and oxidase tests. A total of 31 strains that were phenotypically consistent with the Lactobacillus genus were chosen and preserved in 25% MRS glycerol at −70°C until DNA extraction.