This report provides for the first time rapid novel environment friendly cell surface based synthesis of stable gold nanoprisms at room temperature using Penicillium citrinum MTCC9999 biomass. The UV-Visible spectral scan of dispersed gold nanoparticles (GNPs) solution showed absorption maxima at 540 nm due to surface plasma resonance (SPR) of gold nanoparticles. Typical Transmission Electron Microscopic (TEM) images showed that most of them were prism (55%) shaped with a diameter ranging from 20 - 40 nm. These results obtained from TEM correlated well with the data obtained from Dynamic Light Scattering (DLS) experiment. Average zeta potential of GNPs was -20 mV suggesting some biomolecules capped the nanoparticles imparting a net negative charge over it. FTIR analysis also showed that protein molecules were involved in stabilization.