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.

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.

A method of producing chemicals includes providing fermentative cells; co-feeding any of galacturonate and galacturonate polymers with carbohydrates to the fermentative cells; and producing a chemical from the fermentative cells. The fermentative cells may include any of Clostridium acetobutylicum and Clostridium saccharoperbutylacetonicum. The carbohydrates may include any of glucose, mannose, galactose, fructose, arabinose, xylose, sucrose, lactose, maltose, cellobiose, and starch. The method may include providing a substantially equal proportion of the any of galacturonate and galacturonate polymers and the carbohydrates for co-feeding to the fermentative cells. The method may include altering a proportion of the any of galacturonate and galacturonate polymers to the carbohydrates. The method may include modulating a production of the chemical by altering the proportion of the any of galacturonate and galacturonate polymers to the carbohydrates. The chemical may include any of acetate and butyrate.

A method of producing chemicals includes providing fermentative cells; co-feeding any of galacturonate and galacturonate polymers with carbohydrates to the fermentative cells; and producing a chemical from the fermentative cells. The fermentative cells may include any of Clostridium acetobutylicum and Clostridium saccharoperbutylacetonicum. The carbohydrates may include any of glucose, mannose, galactose, fructose, arabinose, xylose, sucrose, lactose, maltose, cellobiose, and starch. The method may include providing a substantially equal proportion of the any of galacturonate and galacturonate polymers and the carbohydrates for co-feeding to the fermentative cells. The method may include altering a proportion of the any of galacturonate and galacturonate polymers to the carbohydrates. The method may include modulating a production of the chemical by altering the proportion of the any of galacturonate and galacturonate polymers to the carbohydrates. The chemical may include any of acetate and butyrate.

A process includes providing a gaseous substrate comprising CO.sub.2 to a bioreactor; providing acetogenic bacteria and medium to the bioreactor to provide a fermentation broth; providing sodium ions to the bioreactor through one or more sodium ion sources; fermenting the gaseous substrate with the acetogenic bacteria in the fermentation broth to produce one or more organic acids; and controlling a butyric acid to an acetic acid ratio by controlling the pH of the fermentation broth. In one aspect, butyric acid to acetic acid ratio increases when the pH of the fermentation broth decreases, and the ratio of butyric acid to acetic acid concentration decreases when the pH of the fermentation broth increases. The acetogenic bacteria includes a sodium translocating ATPase that is active during fermentation in the bioreactor. The sodium ions are provided so that Na.sup.+ is maintained between 1000 to 11000 ppm (g/g) in culture broth.

A process includes providing a gaseous substrate comprising CO.sub.2 to a bioreactor; providing acetogenic bacteria and medium to the bioreactor to provide a fermentation broth; providing sodium ions to the bioreactor through one or more sodium ion sources; fermenting the gaseous substrate with the acetogenic bacteria in the fermentation broth to produce one or more organic acids; and controlling a butyric acid to an acetic acid ratio by controlling the pH of the fermentation broth. In one aspect, butyric acid to acetic acid ratio increases when the pH of the fermentation broth decreases, and the ratio of butyric acid to acetic acid concentration decreases when the pH of the fermentation broth increases. The acetogenic bacteria includes a sodium translocating ATPase that is active during fermentation in the bioreactor. The sodium ions are provided so that Na.sup.+ is maintained between 1000 to 11000 ppm (g/g) in culture broth.

Provided herein are methods of producing carbon-based compounds from the fermentation of cellulosic feedstocks. In certain embodiments, the cellulosic feedstock and/or source of the cellulosic feedstock is grass, guar gum, leaves, cattails, and/or phragmites.

Yeast cells having a reductive TCA pathway from pyruvate or phosphoenolpyruvate to succinate, and which include at least one exogenous gene overexpressing an enzyme in that pathway, further contain an exogenous transhydrogenase gene.

Yeast cells having a reductive TCA pathway from pyruvate or phosphoenolpyruvate to succinate, and which include at least one exogenous gene overexpressing an enzyme in that pathway, further contain an exogenous transhydrogenase gene.

Genetically engineered bacteria, pharmaceutical compositions thereof, and methods of modulating and treating disorders associated with hyperammonemia are disclosed.