Given that vegetative oil is 1.9 times as carbon-dense as glucose per unit mass, we can expect that producing biodiesel directly from an oil crop can afford reductions in biomass yield compared to a process producing biodiesel from a sugar crop via fermentation. To better inform research and development on critical targets for biomass yield as a function of oil content, we determined the competitive biomass yield under uncertainty across potential feedstock oil contents (Figure ). Under assumptions for the best theoretical performance of microbial oil production (i.e., 100% of glucose carbon converted to microbial oil, minimal fermentation costs, and a microbial oil recovery as high as plant oil recovery), a 1% increase in oilcane oil content can be accompanied by (on average) a 1.21 % reduction in biomass yield (relative to the baseline yield of sugarcane) to achieve equivalent profitability. In reality, due to the need for cell growth and respiration (not all carbon is converted to oil) and the significant costs of aerated bioreactor conditions in microbial oil production, the actual affordable loss in oilcane biomass yield can be much greater. While the biomass yield for oilcane 1566 (17.7 DMT•ha -1 •y -1 ) is 31 % lower than the sugarcane wildtype, this biomass yield is just 0.56 % lower than the 5 th percentile of the competitive biomass yield (21.6 [17.8, 22.6] DMT•ha -1 •y -1 in the ICF configuration; Figure ).