Production and evaluation of biodiesel from sweet orange (Citrus sinensis) lipids extracted from waste seeds from the commercial orange juicing process

Authors: Moser, Bryan; Dorado, Christina; Bantchev, Grigor; Moser, Jill; Doll, Kenneth - Ken

Submitted to: Fuel
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/5/2023
Publication Date: 2/18/2023
Citation: Moser, B.R., Dorado, C., Bantchev, G.B., Winkler-Moser, J.K., Doll, K.M. 2023. Production and evaluation of biodiesel from sweet orange (Citrus sinensis) lipids extracted from waste seeds from the commercial orange juicing process. Fuel. 342. Article 127727. https://doi.org/10.1016/j.fuel.2023.127727.
DOI: https://doi.org/10.1016/j.fuel.2023.127727

Interpretive Summary: The citrus industry generates a significant amount of excess biomass when producing juices, such as orange juice, for human consumption. This underutilized biomass causes environmental issues when discarded, so finding uses for this material reduces food industry waste while potentially generating new revenue streams. The waste is a mixture of peels, pulp, and inedible seeds. The seeds contain vegetable oil that had not yet been explored as a feedstock for production of biodiesel. Thus, the objective of the current study was to evaluate the suitability of this oil as a source of biodiesel. Such a result indicated that the fuel was suitable for use as an alternative diesel fuel. Thus, the new biodiesel has good potential to augment the supply of domestic renewable fuels by utilizing excess biomass generated by the citrus industry. These results will be important to the citrus industry, biodiesel producers, distributors, and end-users (customers) because a new biodiesel fuel was described that exhibits favorable fuel properties. This research may ultimately improve market penetration, availability, and public perception of renewable agricultural fuels such as biodiesel, thus affording greater national independence from imported petroleum-based fuels.

Technical Abstract: The citrus industry generates a significant amount of excess biomass when producing juices for human consumption. This underutilized biomass causes environmental issues when discarded, so finding uses for this material reduces waste while potentially generating new revenue streams. Oil (37 wt%) extracted from inedible sweet orange (Citrus sinensis) seeds obtained as waste from the commercial orange juicing process was investigated as a feedstock for production of biodiesel. Fatty acid methyl esters were prepared by sodium methoxide-catalyzed transesterification of sweet orange seed oil. The principal fatty acids identified in the oil were linoleic (33.9%), palmitic (27.8%), and oleic (27.1%) acids. Fuel properties of the resulting biodiesel were compared to ASTM D6751 and EN 14214. The cloud and pour points were 8.7 and 7.9 °C, respectively, and the oxidative stability (110 °C) was 0.7 h. Overall, the methyl esters were within the specifications of the biodiesel standards, except for oxidative stability.