Germanium is a strategic metalloid the security of supply of which is regarded as critical. Typically, it is recovered from by-products of zinc smelting. An inherently new approach pursues germanium recovery from plant biomass (phytomining). By integrating germanium recovery into a biogas production process, there is entire utilisation of biomass. After acid leaching the biomass is used for biogas production, while the leachate subsequently is subjected to germanium extraction. By-metal content is reduced by >= 95 %, and GeO2 is yielded by distillation of GeCl4.