Genomic and metabolic insights into solvent production by Thermoanaerobacterium thermosaccharolyticum GSU5

Document Type: Research Paper

Authors

Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, IQUIBICEN-CONICET, Buenos Aires, Argentina.

Abstract

Thermoanaerobacterium thermosaccharolyticum GSU5 was isolated from animal dung collected in a pasture plain in Buenos Aires, Argentina. This thermophilic and anaerobic microorganism was able to produce butanol and ethanol, but not acetone, using sugars such as xylose, arabinose, glucose, galactose, fructose, sucrose, and cellobiose. Key metabolic enzymes leading to solvent production were identified in its genome. A detailed analysis of the solvent and organic acid biosynthetic pathway genes of sequenced strains revealed new insights into the unique metabolic features of this species. Genes required for the synthesis of acetone are absent in the genomes of all sequenced Thermoanaerobacterium, suggesting that it is a general trait of the genus. Strains able to produce butanol synthesize butyrate through the one step pathway catalyzed by the butyryl-CoA:acetate-CoA transferase (But). The large range of fermentable substrates and the ability to produce both ethanol and butanol without acetone makes this species an interesting candidate for second generation biofuel production.

Graphical Abstract

Genomic and metabolic insights into solvent production by Thermoanaerobacterium thermosaccharolyticum GSU5

Highlights

  • Comparative genome analysis of Thermoanaerobacterium thermosaccharolyticum GSU5 was performed.
  • Ethanol and butanol production from different carbon sources without acetone was achieved.
  • Solventogenic and acidogenic pathways in Thermoanaerobacterium were elucidated.

Keywords