Effect of antioxidant addition on stability and emission aspects of novel biodiesel generated from the yeast Yarrowia lipolytica cultivated on dairy effluent

The continuous utilization of fossil fuel reserves and augmented pollution level leads to inevitable transition toward renewable fuel in transportation sector. Biodiesel is one of the most renowned biofuels across the energy sector in recent decade. Even though biodiesel has many advantages, the stability is a key concern on downside of biodiesel. The presence of oxygenated compounds in biodiesel leads to faster rancidation during prolonged storage period. This research focuses on producing biodiesel from diary waste and assesses the influence of synthetic antioxidant on its stability. The addition of antioxidant showed a significant increase in the induction period (IP) of biodiesel. Tert-butyl hydroquinone (TBHQ) showed superior Induction Period (IP) of 15.28 h at 110 °C, which is due to its radical suppression behavior during ageing. The thermal ageing results also confirmed the potential of the TBHQ blend with the least ageing rate of 0.08 cSt/h. The biodiesel samples showed signs of dehydration and polymerization after ageing, which is detected by FTIR spectra. Finally, the engine testing showed that antioxidant reduces dangerous NOx emission with minor sacrifice toward performance aspects. From the results, it can be seen that the biodiesel from yeast grown dairy wastewater can be a suitable competitor in the alternate fuel market.