Biomedical Engineering Reference
In-Depth Information
Table 5.3
(continued)
Obligately
heterofermentative
b
Facultatively
heterofermentative
Obligately
homofermentative
W. hellenica
W . kandleri
W. paramesenteroides
W. viridescens
E. Enterococcus, Lb
.
Lactobacillus
,
Lc
.
Lactococcus
,
Le
.
Leuconostoc
,
P
.
Pediococcus
,
S
.
Streptococcus
,
W
.
Weissella
a
Data compiled from [
57,
58,
68,
70
]
b
Classification in glucose fermentation types according to Felis and Dellaglio [
59
]
sanfrancisco
” [
75
] (now
Lactobacillus sanfranciscensis
) and “
Lactobacillus rossii
”
[
76
] (now
Lb. rossiae
), and the synonymization of species, such as the recognition
of
Lactobacillus suntoryeus
as a synonym of
Lactobacillus helveticus
[
77
] , can take
a while to be introduced in subsequent taxonomic literature.
Triggered by the introduction of molecular DNA-based taxonomic methods in
sourdough microbiology and the growing number of 16S rRNA gene sequences in
public databases, in recent years many new
Lactobacillus
species have been
described which were first isolated from a sourdough environment. Since 2000, 13
new
Lactobacillus
species originally isolated from sourdoughs have been proposed,
i.e.,
Lactobacillus frumenti
[
78
] ,
Lactobacillus mindensis
[
79
] ,
Lactobacillus spich-
eri
[
80
]
, Lactobacillus acidifarinae
[
81
] ,
Lactobacillus zymae
[
81
] ,
Lactobacillus
hammesii
[
82
] ,
Lb. rossiae
[
76
] ,
Lactobacillus siliginis
[
83
] ,
Lactobacillus nanten-
sis
[
84
] ,
Lactobacillus secaliphilus
[
85
] ,
Lactobacillus crustorum
[
86
] ,
Lactobacillus
namurensis
[
87
] , and
Lactobacillus nodensis
[
88
] (Table
5.3
). However, many of
these species have only been reported once or are rarely isolated from this type of
fermented food, and are represented by only a few strains. Therefore, it is not clear
which of these species are really typical for sourdough environments and if so, what
their geographical distribution is. In fact, only a few
Lactobacillus
species such as
the obligately heterofermentative
Lb. sanfranciscensis
and the facultatively hetero-
fermentative
Lb. paralimentarius
seem to be optimally adapted to this specific envi-
ronment and are rarely isolated from other sources. Other heterofermentative species
such as
Lactobacillus brevis
and the facultatively heterofermentative
Lb. plantarum
are also frequently isolated from fermented sourdoughs, but have also been found
in many other food and nonfood environments [
69
] .
Although the LAB microbiota of sourdoughs is clearly dominated by lactoba-
cilli, other less predominant or subdominant LAB species may also be found,
including members of the genera
Weissella
,
Pediococcus
,
Leuconostoc
,
Lactococcus
,
Enterococcus
and
Streptococcus
(Table
5.3
). Of these, specific species of
Weissella
,
Pediococcus,
and
Leuconostoc
are particularly well adapted to survive and grow in
plant-derived materials [
57,
89
]. The taxonomy of the latter three genera is much
less complex than in
Lactobacillus
, and their presence in sourdoughs is restricted to
only a few species. Weissellas are obligately heterofermentative LAB of which a
