TECHNOLOGY FOCUS - POLYMERS - Preferred Matrix Materials: Polymers, preferably thermoplastics, elastomers or thermoplastic elastomers, especially thermoplastics based on halogenated and/or sulfonated polyalkenes (preferably halogenated and/or sulfonated polyethylene), elastomers based on non-polar rubbers (preferably natural rubber, butadiene rubber or ethylene-propylene-diene copolymer), elastomers based on polar rubbers (preferably halogenated rubber, especially fluoro-rubber, chloroprene rubber, chlorobutyl rubber or more especially bromobutyl rubber, and nitrile rubber or acrylate rubber) and thermoplastic rubbers with the above thermoplastic and elastomer components (in which the amount of thermoplastic component is preferably at least as much as the amount of elastomer). The matrix may also contain a support material. The membrane (2) has a thickness of 0.05-1 (preferably 0.1-0.2) mm.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Support Materials: Molecular sieves, preferably with a high content of water of crystallisation, especially metal-aluminum silicates of formula Men((AlO2)x.(SiO2)y).mH2O in whichMe = a Main Group 1 or 2 metal, preferably sodium;n = 86;x = 86;y = 106;m = at least 100, preferably at least 200, most preferably 276preferably sodium aluminum silicate corresponding to the above formula with m = 276. This support material is loaded with the protein so as to form a molecular sieve/protein adduct, preferably with partial dehydration of the molecular sieve.    TECHNOLOGY FOCUS - BIOLOGY - Preferred Proteins: Proteins with temperature resistance up to 100 (preferably up to 130) degreesC, especially gramicidin, ATP-ase, thioredoxin and micro-organisms of the groups Halobacterium halobium (especially Bacteriorhodopsin), Micrococcus, Actinomyces bacterium, Streptomyces bacterium and yeasts. These microorganisms are killed after growth and incorporation into the membrane. The channel-forming protein comprises a water-filled pore.    TECHNOLOGY FOCUS - ELECTRICAL POWER AND ENERGY - Preferred Application: As a low-temperature fuel cell.