The Experts below are selected from a list of 297 Experts worldwide ranked by ideXlab platform
Simon Dusseaux - One of the best experts on this subject based on the ideXlab platform.
-
metabolic engineering of clostridium acetobutylicum atcc 824 for the high yield production of a biofuel composed of an Isopropanol butanol ethanol mixture
Metabolic Engineering, 2013Co-Authors: Simon Dusseaux, Christian Croux, Philippe Soucaille, Isabelle MeynialsallesAbstract:Clostridium acetobutylicum was metabolically engineered to produce a biofuel consisting of an Isopropanol/butanol/ethanol mixture. For this purpose, different synthetic Isopropanol operons were constructed and introduced on plasmids in a butyrate minus mutant strain (C. acetobutylicum ATCC 824 Δcac15ΔuppΔbuk). The best strain expressing the Isopropanol operon from the thl promoter was selected from batch experiments at pH 5. By further optimizing the pH of the culture, a biofuel mixture with almost no by-products was produced at a titer, a yield and productivity never reached before, opening the opportunities to develop an industrial process for alternative biofuels with Clostridial species. Furthermore, by performing in vivo and in vitro flux analysis of the synthetic Isopropanol pathway, this flux was identified to be limited by the [acetate]int and the high Km of CoA-transferase for acetate. Decreasing the Km of this enzyme using a protein engineering approach would be a good target for improving Isopropanol production and avoiding acetate accumulation in the culture medium.
-
Metabolic engineering of Clostridium acetobutylicum ATCC 824 for the high-yield production of a biofuel composed of an Isopropanol/butanol/ethanol mixture
Metabolic Engineering, 2013Co-Authors: Simon Dusseaux, Christian Croux, Philippe Soucaille, Isabelle Meynial SallesAbstract:Clostridium acetobutylicum was metabolically engineered to produce a biofuel consisting of an Isopropanol/butanol/ethanol mixture. For this purpose, different synthetic Isopropanol operons were constructed and introduced on plasmids in a butyrate minus mutant strain (C acetobutylicum ATCC 824 Delta cac15 Delta upp Delta buk). The best strain expressing the Isopropanol operon from the thl promoter was selected from batch experiments at pH 5. By further optimizing the pH of the culture, a biofuel mixture with almost no by-products was produced at a titer, a yield and productivity never reached before, opening the opportunities to develop an industrial process for alternative biofuels with Clostridia! species. Furthermore, by performing in vivo and in vitro flux analysis of the synthetic Isopropanol pathway, this flux was identified to be limited by the [acetate](int) and the high Km of CoA-transferase for acetate. Decreasing the Km of this enzyme using a protein engineering approach would be a good target for improving Isopropanol production and avoiding acetate accumulation in the culture medium. (C) 2013 Elsevier Inc. All rights reserved.
Christian Croux - One of the best experts on this subject based on the ideXlab platform.
-
metabolic engineering of clostridium acetobutylicum atcc 824 for the high yield production of a biofuel composed of an Isopropanol butanol ethanol mixture
Metabolic Engineering, 2013Co-Authors: Simon Dusseaux, Christian Croux, Philippe Soucaille, Isabelle MeynialsallesAbstract:Clostridium acetobutylicum was metabolically engineered to produce a biofuel consisting of an Isopropanol/butanol/ethanol mixture. For this purpose, different synthetic Isopropanol operons were constructed and introduced on plasmids in a butyrate minus mutant strain (C. acetobutylicum ATCC 824 Δcac15ΔuppΔbuk). The best strain expressing the Isopropanol operon from the thl promoter was selected from batch experiments at pH 5. By further optimizing the pH of the culture, a biofuel mixture with almost no by-products was produced at a titer, a yield and productivity never reached before, opening the opportunities to develop an industrial process for alternative biofuels with Clostridial species. Furthermore, by performing in vivo and in vitro flux analysis of the synthetic Isopropanol pathway, this flux was identified to be limited by the [acetate]int and the high Km of CoA-transferase for acetate. Decreasing the Km of this enzyme using a protein engineering approach would be a good target for improving Isopropanol production and avoiding acetate accumulation in the culture medium.
-
Metabolic engineering of Clostridium acetobutylicum ATCC 824 for the high-yield production of a biofuel composed of an Isopropanol/butanol/ethanol mixture
Metabolic Engineering, 2013Co-Authors: Simon Dusseaux, Christian Croux, Philippe Soucaille, Isabelle Meynial SallesAbstract:Clostridium acetobutylicum was metabolically engineered to produce a biofuel consisting of an Isopropanol/butanol/ethanol mixture. For this purpose, different synthetic Isopropanol operons were constructed and introduced on plasmids in a butyrate minus mutant strain (C acetobutylicum ATCC 824 Delta cac15 Delta upp Delta buk). The best strain expressing the Isopropanol operon from the thl promoter was selected from batch experiments at pH 5. By further optimizing the pH of the culture, a biofuel mixture with almost no by-products was produced at a titer, a yield and productivity never reached before, opening the opportunities to develop an industrial process for alternative biofuels with Clostridia! species. Furthermore, by performing in vivo and in vitro flux analysis of the synthetic Isopropanol pathway, this flux was identified to be limited by the [acetate](int) and the high Km of CoA-transferase for acetate. Decreasing the Km of this enzyme using a protein engineering approach would be a good target for improving Isopropanol production and avoiding acetate accumulation in the culture medium. (C) 2013 Elsevier Inc. All rights reserved.
Philippe Soucaille - One of the best experts on this subject based on the ideXlab platform.
-
metabolic engineering of clostridium acetobutylicum atcc 824 for the high yield production of a biofuel composed of an Isopropanol butanol ethanol mixture
Metabolic Engineering, 2013Co-Authors: Simon Dusseaux, Christian Croux, Philippe Soucaille, Isabelle MeynialsallesAbstract:Clostridium acetobutylicum was metabolically engineered to produce a biofuel consisting of an Isopropanol/butanol/ethanol mixture. For this purpose, different synthetic Isopropanol operons were constructed and introduced on plasmids in a butyrate minus mutant strain (C. acetobutylicum ATCC 824 Δcac15ΔuppΔbuk). The best strain expressing the Isopropanol operon from the thl promoter was selected from batch experiments at pH 5. By further optimizing the pH of the culture, a biofuel mixture with almost no by-products was produced at a titer, a yield and productivity never reached before, opening the opportunities to develop an industrial process for alternative biofuels with Clostridial species. Furthermore, by performing in vivo and in vitro flux analysis of the synthetic Isopropanol pathway, this flux was identified to be limited by the [acetate]int and the high Km of CoA-transferase for acetate. Decreasing the Km of this enzyme using a protein engineering approach would be a good target for improving Isopropanol production and avoiding acetate accumulation in the culture medium.
-
Metabolic engineering of Clostridium acetobutylicum ATCC 824 for the high-yield production of a biofuel composed of an Isopropanol/butanol/ethanol mixture
Metabolic Engineering, 2013Co-Authors: Simon Dusseaux, Christian Croux, Philippe Soucaille, Isabelle Meynial SallesAbstract:Clostridium acetobutylicum was metabolically engineered to produce a biofuel consisting of an Isopropanol/butanol/ethanol mixture. For this purpose, different synthetic Isopropanol operons were constructed and introduced on plasmids in a butyrate minus mutant strain (C acetobutylicum ATCC 824 Delta cac15 Delta upp Delta buk). The best strain expressing the Isopropanol operon from the thl promoter was selected from batch experiments at pH 5. By further optimizing the pH of the culture, a biofuel mixture with almost no by-products was produced at a titer, a yield and productivity never reached before, opening the opportunities to develop an industrial process for alternative biofuels with Clostridia! species. Furthermore, by performing in vivo and in vitro flux analysis of the synthetic Isopropanol pathway, this flux was identified to be limited by the [acetate](int) and the high Km of CoA-transferase for acetate. Decreasing the Km of this enzyme using a protein engineering approach would be a good target for improving Isopropanol production and avoiding acetate accumulation in the culture medium. (C) 2013 Elsevier Inc. All rights reserved.
Anthony J Sinskey - One of the best experts on this subject based on the ideXlab platform.
-
over expression of groesl in cupriavidus necator for heterotrophic and autotrophic Isopropanol production
Metabolic Engineering, 2017Co-Authors: Jillian Marc, Estelle Grousseau, Nathalie Gorret, Anthony J Sinskey, Eric Lombard, Stephane GuillouetAbstract:Abstract We previously reported a metabolic engineering strategy to develop an Isopropanol producing strain of Cupriavidus necator leading to production of 3.4 g L−1 Isopropanol. In order to reach higher titers, Isopropanol toxicity to the cells has to be considered. A toxic effect of Isopropanol on the growth of C. necator has been indeed observed above a critical value of 15 g L−1. GroESL chaperones were first searched and identified in the genome of C. necator. Native groEL and groES genes from C. necator were over-expressed in a strain deleted for PHA synthesis. We demonstrated that over-expressing groESL genes led to a better tolerance of the strain towards exogenous Isopropanol. GroESL genes were then over-expressed within the best engineered Isopropanol producing strain. A final Isopropanol concentration of 9.8 g L−1 was achieved in fed-batch culture on fructose as the sole carbon source (equivalent to 16 g L−1 after taking into account evaporation). Cell viability was slightly improved by the chaperone over-expression, particularly at the end of the fermentation when the Isopropanol concentration was the highest. Moreover, the strain over-expressing the chaperones showed higher enzyme activity levels of the 2 heterologous enzymes (acetoacetate carboxylase and alcohol dehydrogenase) of the Isopropanol synthetic operon, translating to a higher specific production rate of Isopropanol at the expense of the specific production rate of acetone. Over-expressing the native chaperones led to a 9–18% increase in the Isopropanol yield on fructose.
-
Isopropanol production with engineered cupriavidus necator as bioproduction platform
Applied Microbiology and Biotechnology, 2014Co-Authors: Estelle Grousseau, Nathalie Gorret, Stephane Guillouet, Jingnan Lu, Anthony J SinskeyAbstract:Alleviating our society’s dependence on petroleum-based chemicals has been highly emphasized due to fossil fuel shortages and increasing greenhouse gas emissions. Isopropanol is a molecule of high potential to replace some petroleum-based chemicals, which can be produced through biological platforms from renewable waste carbon streams such as carbohydrates, fatty acids, or CO2. In this study, for the first time, the heterologous expression of engineered Isopropanol pathways were evaluated in a Cupriavidus necator strain Re2133, which was incapable of producing poly-3-hydroxybutyrate [P(3HB)]. These synthetic production pathways were rationally designed through codon optimization, gene placement, and gene dosage in order to efficiently divert carbon flow from P(3HB) precursors toward Isopropanol. Among the constructed pathways, Re2133/pEG7c overexpressing native C. necator genes encoding a β-ketothiolase, a CoA-transferase, and codon-optimized Clostridium genes encoding an acetoacetate decarboxylase and an alcohol dehydrogenase produced up to 3.44 g l-1 Isopropanol in batch culture, from fructose as a sole carbon source, with only 0.82 g l-1 of biomass. The intrinsic performance of this strain (maximum specific production rate 0.093 g g-1 h-1, yield 0.32 Cmole Cmole-1) corresponded to more than 60 % of the respective theoretical performance. Moreover, the overall Isopropanol production yield (0.24 Cmole Cmole-1) and the overall specific productivity (0.044 g g-1 h-1) were higher than the values reported in the literature to date for heterologously engineered Isopropanol production strains in batch culture. Strain Re2133/pEG7c presents good potential for scale-up production of Isopropanol from various substrates in high cell density cultures.
-
Isopropanol production with engineered Cupriavidus necator as bioproduction platform
Applied Microbiology and Biotechnology, 2014Co-Authors: Estelle Grousseau, Nathalie Gorret, Stephane Guillouet, Anthony J SinskeyAbstract:Alleviating our society's dependence on petroleum-based chemicals has been highly emphasized due to fossil fuel shortages and increasing greenhouse gas emissions. Isopropanol is a molecule of high potential to replace some petroleum-based chemicals, which can be produced through biological platforms from renewable waste carbon streams such as carbohydrates, fatty acids, or CO2. In this study, for the first time, the heterologous expression of engineered Isopropanol pathways were evaluated in a Cupriavidus necator strain Re2133, which was incapable of producing poly-3-hydroxybutyrate [P(3HB)]. These synthetic production pathways were rationally designed through codon optimization, gene placement, and gene dosage in order to efficiently divert carbon flow from P(3HB) precursors toward Isopropanol. Among the constructed pathways, Re2133/pEG7c overexpressing native C. necator genes encoding a beta-ketothiolase, a CoA-transferase, and codon-optimized Clostridium genes encoding an acetoacetate decarboxylase and an alcohol dehydrogenase produced up to 3.44 g l(-1) Isopropanol in batch culture, from fructose as a sole carbon source, with only 0.82 g l(-1) of biomass. The intrinsic performance of this strain (maximum specific production rate 0.093 g g(-1) h(-1), yield 0.32 Cmole Cmole(-1)) corresponded to more than 60 % of the respective theoretical performance. Moreover, the overall Isopropanol production yield (0.24 Cmole Cmole(-1)) and the overall specific productivity (0.044 g g(-1) h(-1)) were higher than the values reported in the literature to date for heterologously engineered Isopropanol production strains in batch culture. Strain Re2133/pEG7c presents good potential for scale-up production of Isopropanol from various substrates in high cell density cultures.
Estelle Grousseau - One of the best experts on this subject based on the ideXlab platform.
-
over expression of groesl in cupriavidus necator for heterotrophic and autotrophic Isopropanol production
Metabolic Engineering, 2017Co-Authors: Jillian Marc, Estelle Grousseau, Nathalie Gorret, Anthony J Sinskey, Eric Lombard, Stephane GuillouetAbstract:Abstract We previously reported a metabolic engineering strategy to develop an Isopropanol producing strain of Cupriavidus necator leading to production of 3.4 g L−1 Isopropanol. In order to reach higher titers, Isopropanol toxicity to the cells has to be considered. A toxic effect of Isopropanol on the growth of C. necator has been indeed observed above a critical value of 15 g L−1. GroESL chaperones were first searched and identified in the genome of C. necator. Native groEL and groES genes from C. necator were over-expressed in a strain deleted for PHA synthesis. We demonstrated that over-expressing groESL genes led to a better tolerance of the strain towards exogenous Isopropanol. GroESL genes were then over-expressed within the best engineered Isopropanol producing strain. A final Isopropanol concentration of 9.8 g L−1 was achieved in fed-batch culture on fructose as the sole carbon source (equivalent to 16 g L−1 after taking into account evaporation). Cell viability was slightly improved by the chaperone over-expression, particularly at the end of the fermentation when the Isopropanol concentration was the highest. Moreover, the strain over-expressing the chaperones showed higher enzyme activity levels of the 2 heterologous enzymes (acetoacetate carboxylase and alcohol dehydrogenase) of the Isopropanol synthetic operon, translating to a higher specific production rate of Isopropanol at the expense of the specific production rate of acetone. Over-expressing the native chaperones led to a 9–18% increase in the Isopropanol yield on fructose.
-
Isopropanol production with engineered cupriavidus necator as bioproduction platform
Applied Microbiology and Biotechnology, 2014Co-Authors: Estelle Grousseau, Nathalie Gorret, Stephane Guillouet, Jingnan Lu, Anthony J SinskeyAbstract:Alleviating our society’s dependence on petroleum-based chemicals has been highly emphasized due to fossil fuel shortages and increasing greenhouse gas emissions. Isopropanol is a molecule of high potential to replace some petroleum-based chemicals, which can be produced through biological platforms from renewable waste carbon streams such as carbohydrates, fatty acids, or CO2. In this study, for the first time, the heterologous expression of engineered Isopropanol pathways were evaluated in a Cupriavidus necator strain Re2133, which was incapable of producing poly-3-hydroxybutyrate [P(3HB)]. These synthetic production pathways were rationally designed through codon optimization, gene placement, and gene dosage in order to efficiently divert carbon flow from P(3HB) precursors toward Isopropanol. Among the constructed pathways, Re2133/pEG7c overexpressing native C. necator genes encoding a β-ketothiolase, a CoA-transferase, and codon-optimized Clostridium genes encoding an acetoacetate decarboxylase and an alcohol dehydrogenase produced up to 3.44 g l-1 Isopropanol in batch culture, from fructose as a sole carbon source, with only 0.82 g l-1 of biomass. The intrinsic performance of this strain (maximum specific production rate 0.093 g g-1 h-1, yield 0.32 Cmole Cmole-1) corresponded to more than 60 % of the respective theoretical performance. Moreover, the overall Isopropanol production yield (0.24 Cmole Cmole-1) and the overall specific productivity (0.044 g g-1 h-1) were higher than the values reported in the literature to date for heterologously engineered Isopropanol production strains in batch culture. Strain Re2133/pEG7c presents good potential for scale-up production of Isopropanol from various substrates in high cell density cultures.
-
Isopropanol production with engineered Cupriavidus necator as bioproduction platform
Applied Microbiology and Biotechnology, 2014Co-Authors: Estelle Grousseau, Nathalie Gorret, Stephane Guillouet, Anthony J SinskeyAbstract:Alleviating our society's dependence on petroleum-based chemicals has been highly emphasized due to fossil fuel shortages and increasing greenhouse gas emissions. Isopropanol is a molecule of high potential to replace some petroleum-based chemicals, which can be produced through biological platforms from renewable waste carbon streams such as carbohydrates, fatty acids, or CO2. In this study, for the first time, the heterologous expression of engineered Isopropanol pathways were evaluated in a Cupriavidus necator strain Re2133, which was incapable of producing poly-3-hydroxybutyrate [P(3HB)]. These synthetic production pathways were rationally designed through codon optimization, gene placement, and gene dosage in order to efficiently divert carbon flow from P(3HB) precursors toward Isopropanol. Among the constructed pathways, Re2133/pEG7c overexpressing native C. necator genes encoding a beta-ketothiolase, a CoA-transferase, and codon-optimized Clostridium genes encoding an acetoacetate decarboxylase and an alcohol dehydrogenase produced up to 3.44 g l(-1) Isopropanol in batch culture, from fructose as a sole carbon source, with only 0.82 g l(-1) of biomass. The intrinsic performance of this strain (maximum specific production rate 0.093 g g(-1) h(-1), yield 0.32 Cmole Cmole(-1)) corresponded to more than 60 % of the respective theoretical performance. Moreover, the overall Isopropanol production yield (0.24 Cmole Cmole(-1)) and the overall specific productivity (0.044 g g(-1) h(-1)) were higher than the values reported in the literature to date for heterologously engineered Isopropanol production strains in batch culture. Strain Re2133/pEG7c presents good potential for scale-up production of Isopropanol from various substrates in high cell density cultures.
