Submitted to: Chemical Engineering Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/14/2024
Publication Date: 3/15/2024
Citation: Deshavath, N.N., Woodruff, W., Eller, F.J., Susanto, V., Yang, C., Rao, C.V., Singh, V. 2024. Scale-up of bioethanol and lipid production from oilcane. Chemical Engineering Journal. https://doi.org/10.1016/j.biortech.2024.130594.
DOI: https://doi.org/10.1016/j.biortech.2024.130594

Interpretive Summary: This research describes the processing of oilcane stems into juice and lignocellulosic hydrolysate using a pilot-scale hydrothermal reactor and their subsequent value-added conversion to ethanol and microbial oils using Ethanol Red Saccharomyces cerevisiae and engineered Rhodosporidium toruloides strains, respectively. Rising carbon dioxide emissions and the associated environmental impacts of continued petroleum extraction and refining necessitate the development of alternative and sustainable sources of fuels and chemicals such as bioethanol and microbial oils. Over 100 g/L bioethanol was obtained from Ethanol Red yeast grown on oilcane juice and a lipid titer of over 8 g/L was obtained from R. toruloides grown on oilcane hydrolysate in fermenters. These results demonstrate the feasibility of pilot-scale production of both ethanol and lipids from oilcane biomass hydrolysate as part of an integrated bioconversion strategy.

Technical Abstract: Microbial oils and biofuels are sustainable substitutes for petroleum-derived compounds and may be produced in an integrated biorefinery from biomass sources. Oilcane, an engineered sugarcane variety with superior characteristics as a feedstock for biodiesel production, is a promising candidate for conversion to value-added products. This study describes the processing of oilcane stems into juice and lignocellulosic hydrolysate using a pilot-scale hydrothermal reactor and their subsequent valorization to ethanol and microbial oils using Ethanol Red Saccharomyces cerevisiae and engineered Rhodosporidium toruloides strains, respectively. A bioethanol titer of 106 g/L was obtained from Ethanol Red yeast grown on oilcane juice in a 3-L fermenter for 30 hours, and a lipid titer of 8.8 g/L was obtained from R. toruloides grown on oilcane hydrolysate in a 75-L fermenter for 144 hours. Intracellular oil was subsequently extracted from the R. toruloides cell pellet using supercritical CO2 for downstream characterization, and the observed fatty acid profile was consistent with previous studies on this strain. These results demonstrate the feasibility of pilot-scale lipid production from oilcane biomass hydrolysate as part of an integrated bioconversion strategy.