Landfill leachate, a byproduct of waste decomposition, poses significant environmental challenges owing to its complex organic composition, which facilitates microbial growth. Although classified as wastewater, landfill leachate contains organic compounds that promote microbial proliferation, rendering it a promising source for identifying yeasts with valuable metabolic capabilities. This study focused on isolating and analysing yeasts from leachate collected from the Blang Bintang landfill in Aceh Besar, Indonesia, specifically targeting their dual potential for biofuel production and wastewater treatment. Rhodotorula mucilaginosa was identified as the principal yeast strain using morphological and molecular techniques, including polymerase chain reaction and electrophoresis. When cultured in a nutrient-rich medium (yeast extract, peptone, glucose, and agar), R. mucilaginosa exhibited notable metabolic capabilities, a fat content of 21.6%, indicating its potential as a biofuel feedstock. Furthermore, trials employing synthetic wastewater demonstrated its capacity to significantly reduce pollutants, achieving reductions of 73.22% for phosphates, 43.17% for ammonia, 77.17% for nitrates, 18.75% for nitrites, and an impressive 96.36% for chemical oxygen demand. These findings underscore the dual functionality of R. mucilaginosa as a viable biofuel feedstock and an effective agent for wastewater treatment. This study suggests opportunities for developing integrated systems combining biofuel production and wastewater treatment, enhancing resource efficiency, and promoting environmental sustainability. This approach addresses energy needs while mitigating ecological pollution arising from leachate, presenting a comprehensive solution to two significant environmental challenges.