<p>Modern industry, reliant on petroleum-derived synthetic emulsifiers, faces an urgent need for more sustainable and environmentally friendly solutions. In this context, bioemulsifiers emerge as a powerful alternative, demonstrating superior emulsifying and stabilizing properties that can lead to cleaner and safer industrial processes. This study investigated the bioemulsifier production of eighteen filamentous fungal isolates, including strains of <i>Aspergillus</i>, <i>Paecilomyces</i>, and <i>Trichoderma</i>, sourced from a petroleum waste landfill. All isolates effectively emulsified motor oil (E₂₄ &gt; 90%) and produced stable emulsions lasting up to three months. Bioemulsifiers from <i>Aspergillus flavus</i> 85b and <i>Trichoderma koningii</i> 96b were extracted using ethanol precipitation and characterized for emulsifying activity. While the bioemulsifier extract from <i>A</i>. <i>flavus</i> A85b emulsified crude, motor, and diesel oils, <i>T</i>. <i>koningii</i> A96b’s extract emulsified crude and motor, but not diesel oil. These bioemulsifiers formed stable emulsions even at concentrations of 50&#xa0;µg.mL^− 1 and under challenging conditions, including high salinity (up to 30% NaCl) and elevated temperature (121&#xa0;°C). Their anionic nature was confirmed through double diffusion on agar, and Fourier-transform infrared spectroscopy suggested a composition of carbohydrates, amino acids, and lipids. Ultimately, these findings highlight fungi from contaminated environments as a sustainable source of stable bioemulsifiers for various industrial and bioremediation applications. </p>