The present invention relates to a new strain of Clostridium acetobutylicum modified to be unable to produce hydrogen and its use for the continuous production of bulk chemicals such as lactate, 1,3-propanediol, ethanol, butanol, isobutanol, 1,3-butanediol, acetate, acetone, isopropanol, 3-hydroxy-3-methylbutyrate and isobutene at high yield.

The invention relates to a plastic compound comprising at least one polyolefin and a biological entity that degrades said polyolefin. The invention further relates to a process for preparing a plastic article wherein at least one polyolefin and one biological entity that degrades said polyolefin are mixed at a temperature at which the polyolefin is in a partially or totally molten state.

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.

Provided herein are composition and process for using a device for the reduction of the oxidized state of phosphorylated or non-phosphorylated nicotinamide adenine dinucleotide to the reduced state, using a catalyst to enable the reduction of the oxidized form of the phosphorylated or non-phosphorylated nicotinamide adenine dinucleotide by hydrogen, and methods for providing the hydrogen.

The invention provides non-naturally occurring microbial organisms containing butadiene or 2,4-pentadienoate pathways comprising at least one exogenous nucleic acid encoding a butadiene or 2,4-pentadienoate pathway enzyme expressed in a sufficient amount to produce butadiene or 2,4-pentadienoate. The organism can further contain a hydrogen synthesis pathway. The invention additionally provides methods of using such microbial organisms to produce butadiene or 2,4-pentadienoate by culturing a non-naturally occurring microbial organism containing butadiene or 2,4-pentadienoate pathways as described herein under conditions and for a sufficient period of time to produce butadiene or 2,4-pentadienoate. Hydrogen can be produced together with the production of butadiene or 2,4-pentadienoate.

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.

In a process for producing formate, a mixed enzyme by mixing hydrogenase (H.sub.2ase) with oxygen tolerance and formate dehydrogenase (FDH) with oxygen tolerance is prepared, and the mixed enzyme and a gas including H.sub.2, CO.sub.2 and NAD.sup.+ are mixed such that formate may be produced even in the presence of oxygen, and thereby utilizing hydrogen sources including oxygen, such as coke oven gas.

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.

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 an algal 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.