Mesoporous cellular siliceous foams (MCF) and hierarchical porous carbons are prepared and functionalized to tailor the interactions between glucose-6-phosphate dehydrogenase (G6PDH) from Leuconostoc mesenteroides and the surface of the porous supports. The electrostatic properties of the surfaces were investigated with zeta potential titrations and the porosity was determined by gas adsorption and mercury porosimetry. The hydrophobicity of the porous carbons even after oxidation resulted in low uptake, high leaching, and low activities. In contrast, high loading densities of up to 110 mg g−1 support were observed with aminopropyl-modified MCF as a result of strong electrostatic interactions. G6PDH was used here to produce the cofactor NADPH under conversion of Glucose-6-phosphate to 6-phosphogluconate (Scheme 2). The activity of the protein in this reaction was almost retained and high thermal and storage stabilities have been observed compared to the free enzyme. These results show that an effective conversion of the substrate Glucose-6-phosphate coupled to a production of the cofactor NADPH from NADP+ was achieved by successful immobilization of G6PDH on MCF.