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Chapter II Review of Literature
aldolase and phosphoketolase and therefore, not only ferment hexose but also pentoses (and
often gluconate).
Group C: Obligatory heterofermentavie lactobacilli: the phospogluconate pathway
ferments hexoses, yielding lactate, acetic acid (ethanol) and CO2 in equimolar amounts.
Pentose enters in this pathway and may be fermented.
Within these three groups the species are arranged according to their phylogenetic
relationship. Thus, the combination of the letter “Aa” defines a species belonging to the
obligatory homofermentative lactobacilli affiliated in the L. delbrueckii group, whereas “Cb”
means that the species is obligatory heterofermentative phylogenetically belonging to the L.
casei-Pediococcus group.
L. casei species belonging to the group facultatively heterofermentative organism
comes under group B. Two species, L. acetotolerans and L. hamsteri constitute group “Ba”,
means that phylogenetically these organisms fall into the L. delbrueckii group. The presence
of the Lys-Dasp type peptidoglycan is consistent with this grouping.
Group “Bb" contains 15 species, 12 of which contain Lys-Dasp and three DAP in
their peptidoglycan. In contrast to Kandler and Weiss (1986), Hammes and Vogel (1995)
have included into group Bb L. bifermentans since, in agreement with the group definition;
this organism possesses key enzymes, aldolase and phosphoketolase. L. bifermentans is
characterized by fermenting glucose homofermentatively. However, dependent on the pH,
lactate can be metabolized to ethanol, acetic acid and CO2 and H2. The utilization of lactate
(and/or pyruvate) is rather common for group Bb-organisms.
2.2.3 Description of the species
All cells are Gram-positive and non-spore-forming, usually catalase-negative, non-
motile, and facultatively anaerobic unless otherwise stated. The grouping of the species
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