One aspect of the invention relates to a genetically modified thermophilic or mesophilic microorganism, wherein a first native gene is partially, substantially, or completely deleted, silenced, inactivated, or down-regulated, which first native gene encodes a first native enzyme involved in the metabolic production of an organic acid or a salt thereof, thereby increasing the native ability of said thermophilic or mesophilic microorganism to produce lactate or acetate as a fermentation product. In certain embodiments, the aforementioned microorganism further comprises a first non-native gene, which first non-native gene encodes a first non-native enzyme involved in the metabolic production of lactate or acetate. Another aspect of the invention relates to a process for converting lignocellulosic biomass to lactate or acetate, comprising contacting lignocellulosic biomass with a genetically modified thermophilic or mesophilic microorganism.

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 are genetically engineered microbes that include at least a portion of a carbon fixation pathway, and in one embodiment, use molecular hydrogen to drive carbon dioxide fixation. In one embodiment, the genetically engineered microbe is modified to convert acetyl CoA, molecular hydrogen, and carbon dioxide to 3-hydroxypropionate, 4-hydroxybutyrate, acetyl CoA, or the combination thereof at levels greater than a control microbe. Other products may also be produced. Also provided herein are cell free compositions that convert acetyl CoA, molecular hydrogen, and carbon dioxide to 3-hydroxypropionate, 4-hydroxybutyrate, acetyl CoA, or the combination thereof. Also provided herein are methods of using the genetically engineered microbes and the cell free compositions.

Disclosed are methods for efficient fermentation broth recycle, methods for improving bottoms recycle, and methods for converting CO, CO.sub.2, and optionally H.sub.2 to ethanol and other oxygenated products, the methods comprising providing to a bioreactor a gaseous substrate comprising CO, CO.sub.2, and optionally H.sub.2, at least one acetogenic carboxydotrophic bacterium, and a liquid nutrient medium, and providing conditions within the bioreactor for the at least one acetogenic carboxydotrophic bacterium to convert CO, CO.sub.2, and optionally H.sub.2 to at least one oxygenated product. Also disclosed are methods for preparing animal feed and for preparing fertilizer.

The present disclosure provides guided microbial remodeling (GMR) methods for the rational improvement of plant-associated microbes to perform plant-beneficial functions. The GMR methods described herein allow for non-intergeneric genetic optimization of key regulatory networks within the microbes, which improve plant-beneficial functions over wild-type microbes but don't have the risks associated with transgenic approaches (e.g., unpredictable gene function, public and regulatory concerns, etc.). The present disclosure also provides remodeled microbes and compositions thereof. The utilization of remodeled microbes and compositions thereof will enable farmers to realize more productive and predictable crop yields without the nutrient degradation, leaching, or toxic runoff associated with traditional synthetically derived fertilizers.

A genetically modified phototrophic cell for in-vivo production of hydrogen. The phototrophic cell has been genetically modified to the effect that a) at least one of the native photosystem I components has been deleted, b) the native hydrogenase has been deleted, and c) at least one fusion protein is expressed, comprising i. a hydrogenase or hydrogenase component and ii. at least one PSI component, with the proviso that the PSI is complemented by expression of the at least one fusion protein, and the hydrogenase component itself, or together with at least one further hydrogenase component expressibly introduced into the cell, has hydrogenase activity.

The present invention provides a method for efficiently producing L-homophenylalanine and a strain producing L-homophenylalanine. In the present invention, a new route for the synthesis of L-homophenylalanine by a cascade enzymatic method using cheap benzaldehyde and pyruvic acid as raw materials is designed. By constructing the pathway-related enzymes into the same E. coli strain, a recombinant E. coli is obtained, with which L-homophenylalanine is catalytically produced through reaction in a 5 L reactor, with a yield of 100.9 g/L, a conversion rate of 94%, and ee>99%. Compared with the existing main methods for producing L-HPA, the production cost of L-homophenylalanine is greatly reduced. Thus, the present invention has good application prospects.

The present invention relates to a monomeric polypeptide including a single subunit comprising the active site of a [NiFe]-hydrogenase-like protein, said monomeric polypeptide having hydrogenase activity.