US 9,034,619 to DEINOVE titled Recombinant bacteria and the uses thereof for producing ethanol
A recombinant Deinococcus bacterium comprising a recombinant nucleic acid construct encoding a pyruvate decarboxylase (PDC) from Zymomonas and an alcohol dehydrogenase (ADH) from Zymomonas, wherein the PDC and ADH coding sequences are placed in an operon in the recombinant nucleic acid construct, and wherein said recombinant nucleic acid construct is integrated into the genome of the bacterium.
The introduction states:
Bacteria having the capacity to reassemble their genome when disrupted by a stress have been reported in the literature, such as Deinococcus bacteria. Deinococcus is a gram positive bacterium that was isolated in 1956 by Anderson and collaborators. This extremophile organism is resistant to DNA damage by UV and ionizing radiations or by cross-linking agent (mitomycin C) and is tolerant to desiccation.
WO01/023526 shows the unusual resistance of Deinococcus to radiation and further proposes their engineering and use in bioremediation. Patent application no WO2009/063079, unpublished at the priority date of the present application, shows that Deinococcus bacteria can resist to solvents and transform biomass to generate ethanol.
Other stress-resistant bacteria are disclosed in patent application no EP09 305041.7, presently unpublished, as well as methods for their isolation and/or selection, and their ability to produce metabolites such as antibiotics.
Genetically altered gram-positive or Geobacillus strains have been mentioned in WO95/27064 and WO2006/131734. From the industrial perspective, no satisfactory metabolite production has been disclosed for these strains. Furthermore, Geobacillus strains produce spores, which is a substantial drawback for industrial use.
The present invention now shows that the genome of stress-resistant bacteria, particularly Deinococcus bacteria, can be modified to improve their capacity to produce ethanol. More specifically, the present invention shows that it is possible to modify metabolic pathways within stress-resistant bacteria, particularly Deinococcus bacteria in order to increase their performance in the production of ethanol.
Separately, note US 9,029,124 to Joule Unlimited.