Biodiesel is one of the most promising alternative biofuels because it is more environmentally friendly and can be directly used in existing diesel engines. Biodiesel is mainly produced from plant oils, and this may have an impact on food supply. Hence, alternative lipid sources, such as oleaginous fungi, needs to be developed. Studies have shown that the dimorphic organism Mucor circinelloides is capable of producing reasonable amount of ethanol during their aerobic growth. It is also known that these filamentous fungi is also forming high content of lipid bodies in their cells, rich in unsaturated fatty acids. This study was about finding a way of reacting the microbial oils generated by Mucor with its own ethanol, in order to direclty produce Fatty acid ethyl esters, also known as biodiesel. The experiments were designed to handle the presence of water in the reaction, therefore, different catalysts were used in the reactions, including the lipase from Mucor miehei, as described in previous studies. The main purpose is funding the best efficiency, leading to a product that fulfills the specifications established by the American standards specifications, and resulting in the minimum environmental impact.