skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Analysis of Metabolic Pathways and Fluxes in a Newly Discovered Thermophilic and Ethanol-Tolerant Geobacillus Strain

Abstract

A recently discovered thermophilic bacterium, Geobacillus thermoglucosidasius M10EXG, ferments a range of C5 (e.g., xylose) and C6 sugars (e.g., glucose) and istolerant to high ethanol concentrations (10percent, v/v). We have investigated the central metabolism of this bacterium using both in vitro enzyme assays and 13C-based flux analysis to provide insights into the physiological properties of this extremophile and explore its metabolism for bio-ethanol or other bioprocess applications. Our findings show that glucose metabolism in G. thermoglucosidasius M10EXG proceeds via glycolysis, the pentose phosphate pathway, and the TCA cycle; the Entner?Doudoroff pathway and transhydrogenase activity were not detected. Anaplerotic reactions (including the glyoxylate shunt, pyruvate carboxylase, and phosphoenolpyruvate carboxykinase) were active, but fluxes through those pathways could not be accuratelydetermined using amino acid labeling. When growth conditions were switched from aerobic to micro-aerobic conditions, fluxes (based on a normalized glucose uptake rate of 100 units (g DCW)-1 h-1) through the TCA cycle and oxidative pentose phosphate pathway were reduced from 64+-3 to 25+-2 and from 30+-2 to 19+-2, respectively. The carbon flux under micro-aerobic growth was directed formate. Under fully anerobic conditions, G. thermoglucosidasius M10EXG used a mixed acid fermentation process and exhibited a maximum ethanol yield of 0.38+-0.07 mol mol-1more » glucose. In silico flux balance modeling demonstrates that lactate and acetate production from G. thermoglucosidasius M10EXG reduces the maximum ethanol yieldby approximately threefold, thus indicating that both pathways should be modified to maximize ethanol production.« less

Authors:
; ; ; ; ; ; ;
Publication Date:
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org.:
Physical Biosciences Division
OSTI Identifier:
948038
Report Number(s):
LBNL-1442E
Journal ID: ISSN 0006-3592; BIBIAU; TRN: US200905%%137
DOE Contract Number:  
DE-AC02-05CH11231
Resource Type:
Journal Article
Journal Name:
Biotechnology and Bioengineering
Additional Journal Information:
Journal Name: Biotechnology and Bioengineering; Journal ID: ISSN 0006-3592
Country of Publication:
United States
Language:
English
Subject:
60; ACETATES; AMINO ACIDS; ANAEROBIC CONDITIONS; BIOLOGICAL PATHWAYS; CARBON; CARBOXYLASE; ENZYMES; ETHANOL; FERMENTATION; GLUCOSE; GLYCOLYSIS; IN VITRO; LACTATES; METABOLISM; PENTOSES; PHOSPHATES; PHOSPHOENOLPYRUVATE; SACCHARIDES; SILICA; STRAINS; XYLOSE; C5 sugar; micro-aerobic; TCA cycle; anaplerotic pathway; flux balance model

Citation Formats

Tang, Yinjie J, Sapra, Rajat, Joyner, Dominique, Hazen, Terry C, Myers, Samuel, Reichmuth, David, Blanch, Harvey, and Keasling, Jay D. Analysis of Metabolic Pathways and Fluxes in a Newly Discovered Thermophilic and Ethanol-Tolerant Geobacillus Strain. United States: N. p., 2009. Web.
Tang, Yinjie J, Sapra, Rajat, Joyner, Dominique, Hazen, Terry C, Myers, Samuel, Reichmuth, David, Blanch, Harvey, & Keasling, Jay D. Analysis of Metabolic Pathways and Fluxes in a Newly Discovered Thermophilic and Ethanol-Tolerant Geobacillus Strain. United States.
Tang, Yinjie J, Sapra, Rajat, Joyner, Dominique, Hazen, Terry C, Myers, Samuel, Reichmuth, David, Blanch, Harvey, and Keasling, Jay D. 2009. "Analysis of Metabolic Pathways and Fluxes in a Newly Discovered Thermophilic and Ethanol-Tolerant Geobacillus Strain". United States. https://www.osti.gov/servlets/purl/948038.
@article{osti_948038,
title = {Analysis of Metabolic Pathways and Fluxes in a Newly Discovered Thermophilic and Ethanol-Tolerant Geobacillus Strain},
author = {Tang, Yinjie J and Sapra, Rajat and Joyner, Dominique and Hazen, Terry C and Myers, Samuel and Reichmuth, David and Blanch, Harvey and Keasling, Jay D},
abstractNote = {A recently discovered thermophilic bacterium, Geobacillus thermoglucosidasius M10EXG, ferments a range of C5 (e.g., xylose) and C6 sugars (e.g., glucose) and istolerant to high ethanol concentrations (10percent, v/v). We have investigated the central metabolism of this bacterium using both in vitro enzyme assays and 13C-based flux analysis to provide insights into the physiological properties of this extremophile and explore its metabolism for bio-ethanol or other bioprocess applications. Our findings show that glucose metabolism in G. thermoglucosidasius M10EXG proceeds via glycolysis, the pentose phosphate pathway, and the TCA cycle; the Entner?Doudoroff pathway and transhydrogenase activity were not detected. Anaplerotic reactions (including the glyoxylate shunt, pyruvate carboxylase, and phosphoenolpyruvate carboxykinase) were active, but fluxes through those pathways could not be accuratelydetermined using amino acid labeling. When growth conditions were switched from aerobic to micro-aerobic conditions, fluxes (based on a normalized glucose uptake rate of 100 units (g DCW)-1 h-1) through the TCA cycle and oxidative pentose phosphate pathway were reduced from 64+-3 to 25+-2 and from 30+-2 to 19+-2, respectively. The carbon flux under micro-aerobic growth was directed formate. Under fully anerobic conditions, G. thermoglucosidasius M10EXG used a mixed acid fermentation process and exhibited a maximum ethanol yield of 0.38+-0.07 mol mol-1 glucose. In silico flux balance modeling demonstrates that lactate and acetate production from G. thermoglucosidasius M10EXG reduces the maximum ethanol yieldby approximately threefold, thus indicating that both pathways should be modified to maximize ethanol production.},
doi = {},
url = {https://www.osti.gov/biblio/948038}, journal = {Biotechnology and Bioengineering},
issn = {0006-3592},
number = ,
volume = ,
place = {United States},
year = {2009},
month = {1}
}