An in silico re-design of the metabolism in Thermotoga maritima for increased biohydrogen production

Nogales, Juan; Guđmundsson, Steinn; Thiele, Ines

doi:10.1016/j.ijhydene.2012.06.032

Cited by 33 publications

(18 citation statements)

References 71 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…G3P is subsequently converted to pyruvate and acetate, and F6P is used for further processing of new glucose molecule. In theory, 8 mol of H 2 per glucose will be produced when the PPP is involved (31,43). Since the PPP generates NAD(P)H, a relevant hydrogenase such as Nfn (47, 48) could yield additional reductants for H 2 synthesis and exceed the 4 mol of H 2 /mol of Glc.…”

Section: Discussionmentioning

confidence: 99%

“…Production of H 2 at levels greater than 4 mol/mol of glucose (Glc) is possible if carbon is redirected through the pentose phosphate pathway (PPP). In this case the H 2 yield could be up to 8 mol of H 2 /mol of Glc (31,43). The involvement of the PPP along with the glycolytic pathway offer an explanation for the apparent stoichiometry of metabolites formed from Tma100 and Tma200 (Fig.…”

Section: Isolation Of H 2 -Resistant and H 2 -Overproducing Cell Linementioning

confidence: 92%

See 1 more Smart Citation

Uncoupling Fermentative Synthesis of Molecular Hydrogen from Biomass Formation in Thermotoga maritima

Singh

White

Demi̇rel

et al. 2018

Appl Environ Microbiol

View full text Add to dashboard Cite

When carbohydrates are fermented by the hyperthermophilic anaerobeThermotoga maritima, molecular hydrogen (H2) is formed in strict proportion to substrate availability. Excretion of the organic acids acetate and lactate provide an additional sink for removal of excess reductant. However, mechanisms controlling energy management of these metabolic pathways are largely unexplored. To investigate this topic, transient gene inactivation was used to block lactate production as a strategy to produce spontaneous mutant cell lines that overproduced H2through mutation of unpredicted genetic targets. Single-crossover homologous chromosomal recombination was used to disrupt lactate dehydrogenase (encoded byldh) with a truncatedldhfused to a kanamycin resistance cassette expressed from a native PgroESLpromoter. Passage of the unstable recombinant resulted in loss of the genetic marker and recovery of evolved cell lines, including strain Tma200. Relative to the wild type, and considering the mass balance of fermentation substrate and products, Tma200 grew more slowly, produced H2at levels above the physiologic limit, and simultaneously consumed less maltose while oxidizing it more efficiently. Whole-genome resequencing indicated that the ABC maltose transporter subunit, encoded bymalK3, had undergone repeated mutation, and high-temperature anaerobic [14C]maltose transport assays demonstrated that the rate of maltose transport was reduced. Transfer of themalK3mutation into a clean genetic background also conferred increased H2production, confirming that the mutant allele was sufficient for increased H2synthesis. These data indicate that a reduced rate of maltose uptake was accompanied by an increase in H2production, changing fermentation efficiency and shifting energy management.IMPORTANCEBiorenewable energy sources are of growing interest to mitigate climate change, but like other commodities with nominal value, require innovation to maximize yields. Energetic considerations constrain production of many biofuels, such as molecular hydrogen (H2) because of the competing needs for cell mass synthesis and metabolite formation. Here we describe cell lines of the extremophileThermotoga maritimathat exceed the physiologic limits for H2formation arising from genetic changes in fermentative metabolism. These cell lines were produced using a novel method called transient gene inactivation combined with adaptive laboratory evolution. Genome resequencing revealed unexpected changes in a maltose transport protein. Reduced rates of sugar uptake were accompanied by lower rates of growth and enhanced productivity of H2.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Isolation Of H 2 -Resistant and H 2 -Overproducing Cell Linementioning

confidence: 92%

Uncoupling Fermentative Synthesis of Molecular Hydrogen from Biomass Formation in Thermotoga maritima

Singh

White

Demi̇rel

et al. 2018

Appl Environ Microbiol

View full text Add to dashboard Cite

show abstract

“…For example, most Thermotogae produce hydrogen that may be harvested (e.g., Nguyen et al (2008) and Maru et al (2012)). The hydrogen production of T. maritima can be boosted via metabolic engineering, as was demonstrated by an in silico redesign of its metabolism (Nogales et al 2012). Additionally, while the degradation of sugars by many Thermotogae results in the production of CO 2 and acetate, T. neapolitana has been shown to convert these byproducts to lactic acid when grown in a CO 2 atmosphere, a process suggested to have potential in carbon capture (D'Ippolito et al 2014).…”

Section: The Thermotogaementioning

confidence: 99%

Insights into thermoadaptation and the evolution of mesophily from the bacterial phylum Thermotogae

2015

View full text Add to dashboard Cite

Thermophiles are extremophiles that grow optimally at temperatures >45°C. To survive and maintain function of their biological molecules, they have a suite of characteristics not found in organisms that grow at moderate temperature (mesophiles). At the cellular level, thermophiles have mechanisms for maintaining their membranes, nucleic acids, and other cellular structures. At the protein level, each of their proteins remains stable and retains activity at temperatures that would denature their mesophilic homologs. Conversely, cellular structures and proteins from thermophiles may not function optimally at moderate temperatures. These differences between thermophiles and mesophiles presumably present a barrier for evolutionary transitioning between the 2 lifestyles. Therefore, studying closely related thermophiles and mesophiles can help us determine how such lifestyle transitions may happen. The bacterial phylum Thermotogae contains hyperthermophiles, thermophiles, mesophiles, and organisms with temperature ranges wide enough to span both thermophilic and mesophilic temperatures. Genomic, proteomic, and physiological differences noted between other bacterial thermophiles and mesophiles are evident within the Thermotogae. We argue that the Thermotogae is an ideal group of organisms for understanding of the response to fluctuating temperature and of long-term evolutionary adaptation to a different growth temperature range.Key words: lateral gene transfer, Kosmotoga, Mesotoga, thermostability, stress response. Résumé :Les thermophiles sont des extrémophiles dont la température optimale de croissance se situe au-delà de 45°C. Pour survivre et permettre à leurs biomolécules de bien fonctionner, ils doivent se doter de caractéristiques qu'on ne retrouve pas chez des organismes se développant à des températures intermédiaires (mésophiles). Sur le plan cellulaire, les thermophiles ont des mécanismes permettant de préserver leurs membranes, acides nucléiques et autres structures cellulaires. Au chapitre des protéines, chacune d'entre elles demeure stable et active à des températures qui dénatureraient leurs homologues mésophiles. En revanche, les structures et protéines cellulaires des thermophiles pourraient ne pas fonctionner de manière optimale à des températures intermédiaires. De telles différences entre les thermophiles et les mésophiles auraient tendance à se dresser en travers d'une transition évolutive entre ces deux modes de vie. Par conséquent, l'étude de thermophiles et de mésophiles fortement apparentés pourrait nous permettre d'établir comment surviendraient de telles transitions du mode de vie. Le phylum bactérien Thermotogae regroupe des hyperthermophiles, des thermophiles, des mésophiles et des organismes dont l'intervalle de températures chevauche les plages thermophiles et mésophiles. On observe parmi les Thermotogae des différences sur le plan génomique, protéomique, et physiologique qu'on relève également entre d'autres thermophiles et méso-philes bactériens. Nous soutenons que les Thermot...

show abstract

“…Other applications include biofuels, such as bioethanol (156) or biohydrogen (157), and drug target discovery (158,159). Recent reviews discussing the various applications of GSMMs are available (20,48,(160)(161)(162).…”

Section: Applications and Discussionmentioning

confidence: 99%

In SilicoConstraint-Based Strain Optimization Methods: the Quest for Optimal Cell Factories

Maia

Rocha

2016

Microbiol Mol Biol Rev

116

107

View full text Add to dashboard Cite

SUMMARYShifting from chemical to biotechnological processes is one of the cornerstones of 21st century industry. The production of a great range of chemicals via biotechnological means is a key challenge on the way toward a bio-based economy. However, this shift is occurring at a pace slower than initially expected. The development of efficient cell factories that allow for competitive production yields is of paramount importance for this leap to happen. Constraint-based models of metabolism, together within silicostrain design algorithms, promise to reveal insights into the best genetic design strategies, a step further toward achieving that goal. In this work, a thorough analysis of the mainin silicoconstraint-based strain design strategies and algorithms is presented, their application in real-world case studies is analyzed, and a path for the future is discussed.

show abstract

An in silico re-design of the metabolism in Thermotoga maritima for increased biohydrogen production

Cited by 33 publications

References 71 publications

Uncoupling Fermentative Synthesis of Molecular Hydrogen from Biomass Formation in Thermotoga maritima

Uncoupling Fermentative Synthesis of Molecular Hydrogen from Biomass Formation in Thermotoga maritima

Insights into thermoadaptation and the evolution of mesophily from the bacterial phylum Thermotogae

In SilicoConstraint-Based Strain Optimization Methods: the Quest for Optimal Cell Factories

Contact Info

Product

Resources

About