The development of a composite fixed-bed continuous-flow immobilized alcohol oxidase bioreactor is described for use in the production of drinking water from humidity condensates collected aboard manned spacecraft. The principal organic contaminants of this wastewater stream are low molecular weight alcohols and organic acids. Alcohol oxidase catalyzes the oxidation of short chain primary alcohols to aldehydes at ambient temperatures. The resulting aldehydes are subjected to a second oxidation via the action of a heterogeneous noble metal catalyst to form carboxylic acids which are removed by sorption onto ion exchange resins. Inactivation of the enzyme by hydrogen peroxide has been significantly reduced by coimmobilization of metallic platinum onto the support. The results of ground-based testing using model contaminant solutions and true humidity condensates are reported.