Abstract: Electrodes and configurations for electrochemical bioreactor systems that can use electrical energy as a source of reducing power in fermentation or enzymatic reactions and that can use electron mediators and a biocatalyst, such as cells or enzymes, to produce electricity are disclosed. Example electrodes in the system may comprise: (1) neutral red covalently bound to graphite felt; (2) a carboxylated cellulose bound to the graphite felt, neutral red bound to the carboxylated cellulose, NAD+ bound to the graphite felt, and an oxidoreductase (e.g., fumarate reductase) bound to the graphite felt; or (3) a metal ion electron mediator bound to graphite. Various biocatalysts, such as an oxidoreductase, cells of Actinobacillus succinogenes, cells of Escherichia coli, and sewage sludge, are suitable for use in the electrochemical bioreactor system.

Abstract: A bioreactor includes a fluid containment vessel and a rotating mixing element including radial inflow elements configured to direction fluid radially inwardly of the mixing element and axial out flow elements configured to redirect the radial inward flow in an axial direction. Both the vessel and the mixing element are made from plastic and the vessel comprises a flexible bag supported by a rigid housing. In one embodiment, the mixing element is pneumatically driven by the buoyancy of gas introduced into the vessel and trapped within gas entrapment cups formed on the periphery of the mixing element. As the volumetric capacity of the bioreactor increases, the ratio of the diameter of the mixing element to the width of the vessel decreases, and a gap defined between the bottom of the mixing element and the bottom of the vessel increase.

Abstract: Disclosed are methods using neutral red to mediate the interconversion of chemical and electrical energy. Electrically reduced neutral red has been found to promote cell growth and formation of reduced products by reversibly increasing the ratio of the reduced:oxidized forms of NAD(H) or NADP(H). Electrically reduced neutral red is able to serve as the sole source of reducing power for microbial cell growth. Neutral red is also able to promote conversion of chemical energy to electrical energy by facilitating the transfer of electrons from microbial reducing power to a fuel cell cathode.

Abstract: Electrodes and configurations for electrochemical bioreactor systems that can use electrical energy as a source of reducing power in fermentation or enzymatic reactions and that can use electron mediators and a biocatalyst, such as cells or enzymes, to produce electricity are disclosed. Example electrodes in the system may comprise: (1) neutral red covalently bound to graphite felt (FIG. 1); (2) a carboxylated cellulose bound to the graphite fell, neutral red bound to the carboxylated cellulose, NAD+ to the graphite fell, and an oxidoreductase (e.g., fumarate reductase) bound to the graphite fell; or (3) a metal ion electron mediator bound to graphite. Various biocatalysts, such as an oxidoreductase, cells of Actinobacillus succinogenes, cells of Escherichia coli, and sewage sludge, are suitable for use in the electrochemical bioreactor system.

Abstract: Electrodes and configurations for electrochemical bioreactor systems that can use electrical energy as a source of reducing power in fermentation or enzymatic reactions and that can use electron mediators and a biocatalyst, such as cells or enzymes, to produce electricity are disclosed. Example electrodes in the system may comprise: (1) neutral red covalently bound to graphite felt (FIG. 1); (2) a carboxylated cellulose bound to the graphite fell, neutral red bound to the carboxylated cellulose, NAD+ bound to the graphite fell, and an oxidoreductase (e.g., fumarate reductase) bound to the graphite fell; or (3) a metal ion electron mediator bound to graphite. Various biocatalysts, such as an oxidoreductase, cells of Actinobacillus succinogenes, cells of Escherichia coli, and sewage sludge, are suitable for use in the electrochemical bioreactor system.

Abstract: The present invention describes the cloning and expression of a hyperthermostable xylose isomerase gene in an industrial host and the heat facilitated purification of the enzyme. The hyperthermostable enzyme has unique features sought by the fructose syrup industry.