In this paper, filamentous fungi have been used as biotemplates to integrate gold nanoparticles (Au-NPs) into the cell wall. A new chemical mechanism has been proposed to elucidate the assimilation of Au-NPs by fungi, considering the ionic current that arises in the function of fungal metabolism. After biological components were eliminated, mycelium-like gold microtubes have been obtained using different fungal species as precursors. Mycelium-like gold microtubes replicate the biological shape of fungi, presenting inherent multifunctionality. This work presents two promising applications for this material: high surface area electrodes for electrochemical experiments and substrates for SERS detection of organic molecules such as Rhodamine 6G.