The invention features solutions of water-soluble, oxygen-resistant redox-active species circulated in flow cells to electrochemically capture CO.sub.2 from air or flue gas and release pure CO.sub.2. The method is safe, scalable, and potentially inexpensive, as it utilizes non-volatile and potentially low-cost redox organic and inexpensive inorganic species and can operate at ambient temperature and pressure and can operate at high current densities.

In various exemplary embodiments, the present disclosure provides novel water-absorbent textile-based gas-liquid-solid contactors for carbon dioxide (CO.sub.2) gas separation, as well as novel methods for producing and using these materials. The water-absorbent textile-based contactors of the present invention allow aqueous liquids to penetrate and travel intimately throughout the water-absorbent textile structure. The textile structure comprises many fibers with small diameters which creates a very high surface area. When exposed to a gas, the gas will be in contact with liquid spread throughout the solid wetted textile structure, all three phases gas-liquid-solid are in intimate contact. The textile contactor itself has superior performance compared to conventional packing materials, and, when combined with biocatalysts, the performance improves even more dramatically. By incorporating a biocatalyst, the invention enables use of benign solvents that have otherwise been overlooked in conventional systems due to poor kinetics.

A method for stripping CO.sub.2 from a biocatalyst-containing CO.sub.2-rich absorption solution to produce a biocatalyst-containing CO.sub.2-lean absorption solution and a CO.sub.2-rich gas is provided. The method includes generating a stripping gas from a portion of the biocatalyst-containing CO.sub.2-lean absorption solution in a stripping gas generation unit, and contacting the biocatalyst-containing CO.sub.2-rich absorption solution with the stripping gas in a gas-liquid contactor to produce the CO.sub.2-lean absorption solution and the CO.sub.2-rich gas.

A recombinant microorganism including a genetic modification that increases activity of nitric oxide reductase in the recombinant microorganism, a composition for reducing a concentration of nitric oxide in a sample, the composition including the recombinant microorganism, and a method of reducing a concentration of nitric oxide in a sample, are disclosed.