BACKGROUND : The overreliance on dwindling fossil fuel reserves and the negative climatic effects of using such fuels
are driving the development of new clean energy sources. One such alternative source is hydrogen (
H2), which can be
generated from renewable sources. Parageobacillus thermoglucosidasius is a facultative anaerobic thermophilic bacterium
which is frequently isolated from high temperature environments including hot springs and compost.
RESULTS : Comparative genomics performed in the present study showed that P. thermoglucosidasius encodes two
evolutionary distinct H2-
uptake [Ni-Fe]-hydrogenases and one H2-
evolving hydrogenases. In addition, genes encoding
an anaerobic CO dehydrogenase (CODH) are co-localized with genes encoding a putative H2-
The co-localized of CODH and uptake hydrogenase form an enzyme complex that might potentially be involved
in catalyzing the water-gas shift reaction (CO + H2O
in P. thermoglucosidasius. Cultivation of P. thermoglucosidasius
with an initial gas atmosphere of 50% CO and 50% air showed it to be capable of growth at
elevated CO concentrations (50%). Furthermore, GC analyses showed that it was capable of producing hydrogen at an
equimolar conversion with a final yield of 1.08 H2/
CONCLUSIONS : This study highlights the potential of the facultative anaerobic P. thermoglucosidasius DSM 2542T
developing new strategies for the biohydrogen production.
Additional file 1. Calculation of the gas composition. Description of the
calculation of the gas composition by using the ideal gas law.
Additional file 2. Annotations of the CODH and [Ni-Fe] hydrogenase loci
of P. thermoglucosidasius DSM 2542T.
The locus tags, sizes, protein names
as well as the functions of the proteins in the three [Ni-Fe] hydrogenase
loci and the anaerobic CODH locus of P. thermoglucosidasius DSM 2542T.
BlastP data (locus tag, average amino acid identity, bitscore and e-value)
for the closest non-Parageobacillus orthologue and the top conserved
domain for each P. thermoglucosidasius DSM 2542T
protein are shown.
Additional file 3. Orthologous [Ni-Fe] hydrogenase and anaerobic CODH
loci in Parageobacillus and other taxa. The locus size, G+C content, G+C
deviation of the orthologous [Ni-Fe] hydrogenase and anaerobic CODH
loci of other P. thermoglucosidasius strains and distinct taxa as used in
Figs. 2, 3 and 4. The number of protein orthologous and average amino
acid identity of these proteins to those encoded on the P. thermoglucosidasius
loci are indicated.