The objectives of this study were: (i) to characterize the sustainability of various design alternatives for microbial oil production at a sugarcane biorefinery; (ii) to determine the financial viability and carbon intensity of integrated processing of plant and microbial oils and elucidate the most salient features driving sustainability; and, critically, (iii) to establish targets for oilcane and microbial oil market competitiveness. To this end, we developed and evaluated biorefinery models in BioSTEAM -an open-source platform for the design, simulation, and evaluation of biorefineries-for processing sugarcane and oilcane to biodiesel through fermentation-derived oils with and without cellulosic biomass processing (a total of four biofuel pathways). Model calibration was supported by laboratory experiments to characterize oil recovery from copretreatment of plant and microbial cells. Each biorefinery was evaluated across a landscape of potential technological performance and market conditions to establish research and development targets for sustainable plant and microbial oil production. In particular, the minimum oilcane biomass yield for market competitiveness (as compared to traditional sugarcane) was elucidated across potential oil contents. Cradle-to-grave greenhouse gas emissions were quantified by leveraging BioSTEAM simulation results coupled with inventory data from the Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation (GREET) and ecoinvent 3.7 . Three different allocation methods (displacement, economic, and energy) were employed to compare the carbon intensity (reported as 100-year global warming potential, GWP100) among the multi-product biorefinery configurations. The minimum biodiesel selling price (MBSP) was used as the main profitability indicator. The sensitivity of the MBSP and carbon intensity to feedstock oil content, product prices, and other techno-economic parameters were evaluated using Spearman's rank-order correlation coefficients, facilitated by Monte Carlo uncertainty analysis.