NOVELTY - A cell-free method for large-scale conversion of methane to isobutanol/methane to pyruvate/methane to a biofuel or other chemical compound, involves: combining, in a bioreactor at elevated pressure, methane, oxygen, and cell lysates containing methane monooxygenase, methanol dehydrogenase, and enzymes that catalyze the conversion of formaldehyde to isobutanol, to form a cell-free reaction mixture; and incubating under suitable conditions the cell-free reaction.    USE - As cell-free method for large-scale conversion of methane to isobutanol/methane to pyruvate/methane to a biofuel or other chemical compound (claimed).    ADVANTAGE - The process combines cell-free lysates from methanotrophs with those from other recombinant bacteria in a reactor typically operated at high pressure (e.g. at least 1 bar, or at least 5 bar). The cell-free processes, systems, reactions mixtures, compositions, recombinant organisms, and nucleic acid constructs are considered parts of a platform technology enabling the efficient production of many different biofuels or other chemical compounds from methane or natural gas. The use of a cell-free biosynthetic system does not require the maintenance of cell viability, enables direct monitoring and adjustment of reaction parameters (e.g. substrate feed rates, temperature, pH, pressure, dissolved oxygen), provides a flexible reaction environment, and enables control of carbon and energy flux. The cell-free process addresses mass transfer challenges associated with methane and oxygen solubility by operating under high pressure, providing an organic phase in which methane has greater solubility, and increasing methane bubble and air bubble surface area by injecting gases at high pressure.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following:    (1) a cell-free system for large-scale conversion of methane to isobutanol/methane to pyruvate, comprising a bioreactor that comprises: a gas phase comprising methane and oxygen; and an aqueous phase comprising a cell lysate containing methane monooxygenase, methanol dehydrogenase, and enzymes that catalyze the conversion of formaldehyde to isobutanol; and    (2) new cell lysate of the method.