Figure 2

Effect of pH on the synthesis of (a) silver and (b) gold nanoparticles by L-DOPA induced-melanin derived from Y. lipolytica NCIM 3590. [Reaction mixtures (2 ml) contained 10 μg of melanin at different pH, 1 mM metal salt incubated at 100°C for 10 min. Tubes and lines 1–4 depict pH of 6.0, 8.0, 10.0 and 12.0, respectively]. Effect of salt concentration on the synthesis of (c) silver and (d) gold nanoparticles [Reaction mixtures (2 ml) contained 10 μg of melanin at pH 12.0 and different concentrations of metal salts incubated at 100°C for 10 min. Tubes and lines 1–8 depict salt concentrations of 0.25, 0.5, 0.75, 1.0, 1.25, 1.5, 1.75 and 2.0 mM, respectively; tube and line C depicts a control without melanin].