RESULTS AND DISCUSSION
Morphological, biochemical and genotypic identification
Both phenotypic and genotypic identifications are part
of the first step in the selection of potential probiotic
bacteria [4]. Table 1 summarizes the morphological
and biochemical tests of LAB 18 and 48. Both strains
tested Gram positive and catalase and oxidase negative.
However, LAB 18 showed a coccal morphology, whereas
LAB 48 showed a rod-shaped morphology. Genotypic
systems are becoming valuable tools for use in a wide
range of microorganisms [2, 4]. Genotypic 16S rRNA
identification of microorganisms from probiotic cultures
may be more consistent than the current standard
microbial techniques [2]. On the other hand, this method
has been shown to have issues and limitations. Speciation
relies on the closest match with previously identified
species in the database because the identification is
based on specific sequence homology compared with
a known database generated from previously identified
organisms through conventional methodologies [2, 4].
Because databases have been constantly changing and
increasing, the same sequence may match other taxons
with greater homology. Therefore, at this moment, it is
nearly impossible to confidently know the speciation of
LAB except with very highly characterized isolates [2].
Thus, while 16s RNA sequencing can positively identify
one LAB isolate as unique among several, true accuracy
of homology comparisons is somewhat subjective.