Colonies obtained on MRS agar were extracted and
transferred to 10 mL of broth culture for the enrichment
step. After 24 h of incubation (37°C), screening for isolates
was performed through a primary morphological test
with the use of a fluorescent microscope (BX61; Olympus)
(Olympus, Tokyo, Japan) and biochemical tests,
such as Gram staining and catalase tests. The isolates were
stored in 30% (w/v) glycerol and 10% (w/v) skim milk at
70°C (Mirzaei and Barzgari 2012).
Amplification of 16S rRNA
The amplification of 16S rRNA of Lactobacillus strains
was performed by using one primer pair (16F27 50
-
AGAGTTTGATCMTGGCTCAG-30 and 16R 50
-TACCTTG
TTAGGACTTCACC-30
), as previously reported by Mirzaei
and Barzgari (2012). These primers are genus-specific
and can directly amplify the 16S rRNA (1500 bp) of Lactobacillus
strains. The amplification was performed with a
25 lL final volume containing 0.4 lmol/L primer, 40 ng
of chromosomal DNA, and master mix (Ampliqon, Herlev,
Denmark). The PCR program cycles were set up as
follows: denaturation at 95°C for 4 min, 32 cycles of
94°C for 1 min, 58°C for 1 min, 72°C for 95 sec, and a
final extension at 72°C for 5 min.