Extreme Thermophiles as Metabolic Engineering Platforms: Strategies and Current Perspective

Loder, Andrew J.; Zeldes, Benjamin M.; Conway, Jonathan M.; Counts, James A.; Straub, Christopher T.; Khatibi, Piyum A.; Lee, Laura L.; Vitko, Nicholas P.; Keller, Matthew W.; Rhaesa, Amanda M.; Rubinstein, Gabe M.; Scott, Israel M.; Lipscomb, Gina L.; Adams, Michael W. W.; Kelly, Robert M.

doi:10.1002/9783527807796.ch14

Cited by 5 publications

(2 citation statements)

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“…Using a host that is an efficient natural acetate producer and tolerates relatively high concentrations of acetate may facilitate acetone production. Fortunately, there are a number of fermentative extreme thermophiles that produce acetate as a major fermentation product and for which genetic tools are available (Loder et al, ; Zeldes et al, ).…”

Section: Discussionmentioning

confidence: 99%

A synthetic enzymatic pathway for extremely thermophilic acetone production based on the unexpectedly thermostable acetoacetate decarboxylase from Clostridium acetobutylicum

Zeldes

Straub

Otten

et al. 2018

Biotech & Bioengineering

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One potential advantage of an extremely thermophilic metabolic engineering host (T ≥ 70°C) is facilitated recovery of volatile chemicals from the vapor phase of an active fermenting culture. This process would reduce purification costs and concomitantly alleviate toxicity to the cells by continuously removing solvent fermentation products such as acetone or ethanol, a process we are calling "bio-reactive distillation." Although extremely thermophilic heterologous metabolic pathways can be inspired by existing mesophilic versions, they require thermostable homologs of the constituent enzymes if they are to be utilized in extremely thermophilic bacteria or archaea. Production of acetone from acetyl-CoA and acetate in the mesophilic bacterium Clostridium acetobutylicum utilizes three enzymes: thiolase, acetoacetyl-CoA: acetate CoA transferase (CtfAB), and acetoacetate decarboxylase (Adc). Previously reported biocatalytic pathways for acetone production were demonstrated only as high as 55°C. Here, we demonstrate a synthetic enzymatic pathway for acetone production that functions up to at least 70°C in vitro, made possible by the unusual thermostability of Adc from the mesophile C. acetobutylicum, and heteromultimeric acetoacetyl-CoA:acetate CoA-transferase (CtfAB) complexes from Thermosipho melanesiensis and Caldanaerobacter subterraneus, composed of a highly thermostable α-subunit and a thermally labile β-subunit. The three enzymes produce acetone in vitro at temperatures of at least 70°C, paving the way for bio-reactive distillation of acetone using a metabolically engineered extreme thermophile as a production host.

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Section: Discussionmentioning

confidence: 99%

A synthetic enzymatic pathway for extremely thermophilic acetone production based on the unexpectedly thermostable acetoacetate decarboxylase from Clostridium acetobutylicum

Zeldes

Straub

Otten

et al. 2018

Biotech & Bioengineering

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“…In view of this, certain fermentative anaerobes that are cellulolytic have been considered for bioprocesses that would require less intensive pretreatment, while at the same time leveraging microbial metabolism through molecular genetic tools to directly produce fuels and chemicals. However, while there has been progress, nonmodel microorganisms are not as easily genetically manipulated as E. coli and S. cerevisiae , although this gap is closing . Faced with the choice between metabolic engineering platforms that are natively incapable of lignocellulose deconstruction but have facile genetic systems and the converse, the tide is shifting as genetic tools for natively lignocellulolytic microorganisms improve.…”

Section: Introductionmentioning

confidence: 99%

Novel multidomain, multifunctional glycoside hydrolases from highly lignocellulolytic Caldicellulosiruptor species

et al. 2018

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Biological hydrolysis of microcrystalline cellulose is an uncommon feature in the microbial world, especially among bacteria and archaea growing optimally above 70°C (the so‐called extreme thermophiles). In fact, among this group only certain species in the genus Caldicellulosiruptor are capable of rapid and extensive cellulose degradation. Four novel multidomain glycoside hydrolases (GHs) from Caldicellulosiruptor morganii and Caldicellulosiruptor danielii were produced recombinantly in Caldicellulosiruptor bescii and characterized. These GHs are structurally organized with two or three catalytic domains flanking carbohydrate binding modules from Family 3. Collectively, these enzymes represent GH families 5, 9, 10, 12, 44, 48, and 74, and hydrolyze crystalline cellulose, glucan, xylan, and mannan, the primary carbohydrates in plant biomass. Degradation of microcrystalline cellulose by cocktails of GHs from three Caldicellulosiruptor species demonstrated that synergistic interactions enable mixtures of multiple enzymes to outperform single enzymes, suggesting a community mode of action for lignocellulose utilization in thermal environments. © 2018 American Institute of Chemical Engineers AIChE J, 64: 4218–4228, 2018

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Thermophilic and Halophilic Microorganisms Isolated from Extreme Environments of Turkey, with Potential Biotechnological Applications

Güven

Bekler

Güven

2018

Extremophiles in Eurasian Ecosystems: Ecology, Diversity, and Applications

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Extreme Thermophiles as Metabolic Engineering Platforms: Strategies and Current Perspective

Cited by 5 publications

References 301 publications

A synthetic enzymatic pathway for extremely thermophilic acetone production based on the unexpectedly thermostable acetoacetate decarboxylase from Clostridium acetobutylicum

A synthetic enzymatic pathway for extremely thermophilic acetone production based on the unexpectedly thermostable acetoacetate decarboxylase from Clostridium acetobutylicum

Novel multidomain, multifunctional glycoside hydrolases from highly lignocellulolytic Caldicellulosiruptor species

Thermophilic and Halophilic Microorganisms Isolated from Extreme Environments of Turkey, with Potential Biotechnological Applications

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