The present disclosure is related to genetically engineered microbial strains and related bioprocesses for the production of products from acetyl-CoA. Specifically, the use of dynamically controlled synthetic metabolic valves to reduce the activity of certain enzymes, leads to increased product production in a two-stage process.

The present invention relates to recombinant microorganisms for producing biological hydrogen. In addition, the invention relates to nucleic acid constructs and processes for modifying microorganisms for enabling the production of hydrogen therefrom.

The present invention concerns a new mutant strain of Clostridium acetobutylicum comprising attenuated glycerol kinase activity. In addition, the present invention concerns a consortium of Clostridium comprising at least said mutant strain and at least one other species of Clostridium chosen among C. sporogenes and C. sphenoides. As this modified strain may be adapted for growth and for the production of 1,3-propanediol in an appropriate culture medium with high glycerol content, the invention also relates to a method for the production of 1,3-propanediolandbutyric acid, by culturing at least this mutant strain in an appropriate culture medium.

The present invention concerns a new mutant strain of Clostridium acetobutylicum comprising attenuated glycerol kinase activity. In addition, the present invention concerns a consortium of Clostridium comprising at least said mutant strain and at least one other species of Clostridium chosen among C. sporogenes and C. sphenoides. As this modified strain may be adapted for growth and for the production of 1,3-propanediol in an appropriate culture medium with high glycerol content, the invention also relates to a method for the production of 1,3-propanediol and butyric acid, by culturing at least this mutant strain in an appropriate culture medium.

Methods and compositions are provided for engineering microorganisms, which permit enhanced H.sub.2 production. The methods and compositions provided include novel chimeric gene constructs encoding H.sub.2-forming H.sub.2ase and maturation proteins, allowing for generation of H.sub.2 continuously in large quantities. In one illustrated embodiment, novel engineered algae are provided with increased levels of H.sub.2 production.

Disclosed are methods for engineering bacteria, for example, Thermoanaerobacterium saccharolyticum, that convert biomass to ethanol at high yield by deleting a single gene. Deletion of subunit A or subunit B of the hfs hydrogenase, but not deletion of subunit C or subunit D, results in an increase in ethanol yield.

Provided herein, in some embodiments, are engineered cells and use of the same for increased hydrogen production. In particular, provided herein are genetically engineered cells comprising a polynucleotide encoding a fusion protein comprising a photosystem I (PSI) protein and a bacterial hydrogenase, as well as methods for producing such genetically engineered cells. Also provided herein are methods for increasing hydrogen (H.sub.2) production in cells.

The invention provides genetically engineered microorganisms with modified hydrogenase activity and methods related thereto. Typically, the microorganisms are C1-fixing microorganisms with one or more disruptive mutations in a hydrogenase enzyme or a hydrogenase accessory enzyme. The microorganisms may have improved tolerance to toxins, such as acetylene, isocyanide, ammonium, or nitric oxide, improved production of products, such as ethanol, 2,3-butanediol, and isopropanol, and/or improved fixation of carbon, such as carbon derived from CO or CO.sub.2.

Compositions and methods are provided for an O.sub.2 tolerant FeFe hydrogenase. The hydrogenases of the invention comprise specific amino acid substitutions relative to the native, or wild-type enzymes.

Disclosed are methods for engineering bacteria, for example, Thermoanaerobacterium saccharolyticum, that convert biomass to ethanol at high yield by deleting a single gene. Deletion of subunit A or subunit B of the hfs hydrogenase, but not deletion of subunit C or subunit D, results in an increase in ethanol yield.