Biomasses have significant impact on the development of new solid phase extraction methods for metal analysis. Adsorbent, prepared by incorporating dried biomass (Aspergillus oryzae) immobilized on activated silica, was presently developed for Au(III) enrichment. The main factors affecting the adsorption-desorption process like pH, sample volume, eluent and eluent flow rate were optimized. Under the optimum conditions, good recovery was obtained at about 99.4 ± 0.1 %, performed by Flame Atomic Absorption Spectrometry. At optimized pH 2.0, Au(III) was quantitatively sorbed and recovered with 1:1 mixture of 0.2 M HCl mixed with 0.2 M thiourea. The enrichment factor was found as 125, and the limit of detection is 0.88 μg L-1 whereas limit of quantification is 2.93 μg L-1. The proposed method was successfully applied in the analysis of tap water, pharmaceutical formulated product and synthetically prepared dummy sample. Equilibrium data also were fitted by linear regression methods through Langmuir, Freundlich, Temkin, Dubinin and Radushkevich (D–R) and Harkin –Jura isotherm models.