Life cycle sustainability assessment of microbial oil from organic waste

Microbial oils (MOs) are lipids produced by oleaginous microorganisms, which constitute an alternative to vegetable and fossil-derived oils. They can be produced from organic waste by coupling acidogenic fermentation (AF) with oleaginous fermentation (OF). This study addresses a life cycle sustainability assessment (LCSA) of MO produced from the organic fraction of municipal solid waste. First, a system was modelled using simulation tools. This model combines AF for the production of volatile fatty acids from organic waste, OF for the production of lipid-rich yeasts, and MO extraction. LCSA results indicate the need for improvements in the disruption of yeasts and the overall efficiency of the system. Particularly, slightly acidified thermolysis turned out to involve excessively high steam requirements. An enhanced sustainability performance could be achieved by exploring alternative disruption methods or alternative sources of energy for the production of steam such as biogas from the valorisation of the sludges produced in the system.