BioChem - DOS

Hydrogen and lactic acid synthesis by the wild-type and a laboratory strain of the hyperthermophilic bacterium Thermotoga neapolitana DSMZ 4359T under capnophilic lactic fermentation conditions

International journal of hydrogen energy

Pradhan, Nirakar; Dipasquale, Laura; d'Ippolito, Giuliana; Panico, Antonio; Lens, Piet N.L.; Esposito, Giovanni; Fontana, Angelo

<P><B>Abstract</B></P> <P> <I>Thermotoga neapolitana</I> is a hyperthermophilic eubacterium that produces hydrogen by sugar fermentation. A lab strain of <I>T. neapolitana</I> DSMZ 4359<SUP>T</SUP> maintained in a CO<SUB>2</SUB>-enriched atmosphere showed a stable increase of lactic acid production under capnophilic lactic fermentation (CLF) conditions. The genotypic comparison between the putative mutant (TN-CMut) and the original strain DSMZ 4359<SUP>T</SUP> (WT4359) revealed 88.1 (&plusmn;2.4)% DNA homology. RiboPrint<SUP>&reg;</SUP> and MALDI-TOF mass analyses support a genetic differentiation beyond subspecies level. The phenotypic characterization indicated a high correlation between the two strains, except for the lactic acid production. Under identical operating conditions, the lab mutant produced significantly more lactic acid than the parent strain without impairing the hydrogen yield. The highest divergence between TN-CMut and WT4359 was observed for fermentation of glucose or lactose at 80 &deg;C. Based on these results, we propose that the lab strain is a new subspecies of the genus <I>Thermotoga</I> that is named <I>T. neapolitana</I> subsp. <I>capnolactica</I> with regards to its improved feature to produce lactic acid under capnophilic conditions.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A <I>Thermotoga neapolitana</I> adapted lab strain showed increased lactic acid production. </LI> <LI> DNA&ndash;DNA hybridization showed homology of 88.1% between mutant and wild-type strain. </LI> <LI> Genotyping differences were suggested at subspecies level. </LI> <LI> Phenotypic tests showed comparable H<SUB>2</SUB> yields, but statistically different lactic acid production. </LI> <LI> The lab strain is proposed as a new subspecies named <I>T. neapolitana</I> subsp. <I>capnolactica</I>. </LI> </UL> </P>

2017

Elsevier

0360-3199

1879-3487

42

25

pp.16023-16030

10.1016/j.ijhydene.2017.05.052

http://click.ndsl.kr/servlet/OpenAPIDetailView?keyValue=05787966&target=NART&cn=NART78050968

Thermotoga neapolitana; Hydrogen; Lactic acid; Capnophilic lactic fermentation; Genotype; Phenotype