Dual Utilization of Medicinal and Aromatic Crops as Bioenergy Feedstocks

Authors: ZHELJAZKOV, VALTCHO - Oregon State University; STEWART JR., NEAL - University Of Tennessee; JOYCE, BLAKE - University Of Tennessee; BAXTER, HOLLY - University Of Tennessee; Cantrell, Charles; ASTATKIE, TESS - Dalhousie University

Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/20/2018
Publication Date: 7/20/2018
Citation: Zheljazkov, V.D., Stewart Jr., N., Joyce, B., Baxter, H., Cantrell, C.L., Astatkie, T. 2018. Dual Utilization of Medicinal and Aromatic Crops as Bioenergy Feedstocks. Journal of Agricultural and Food Chemistry. https://doi.org/10.1021/acs.jafc.7b04594.
DOI: https://doi.org/10.1021/acs.jafc.7b04594

Interpretive Summary: Ethanol production in the USA is currently limited to using starch and sugars from corn, and the cost of ethanol is high. Further reduction in the production cost of ethanol from corn and other starch materials is unlikely because this has been thoroughly investigated and technologies are well established. Evaluating species for double utilization is a new approach to add value to lignocellulosic feedstock production. In this study, we evaluated selected essential oil crops peppermint, ‘Scotch’ spearmint, Japanese cornmint, sweet sagewort, and compared them to switchgrass as lignocellulosic feedstock for ethanol production and for production of high-value natural products. Estimated ethanol production from the alternative crops were similar to the one from switchgrass. Additional incomes from the essential oil sells would be $1,055 - 5,132 ha-1 from peppermint, $1,309 - 5,580 ha-1 from spearmint, $510 - 2,460 ha-1 from Japanese cornmint, and $3,613 ha-1 from sweet sagewort. The tested species could be used as supplemental crops for biofuel feedstock in irrigated areas. The advantage of the proposed crops over other lignocellulosic species is the production of high-value natural products, which may offset production costs, foster the development of new value-added products, and be more attractive to growers.

Technical Abstract: Evaluating species for double utilization is a new approach to add value to lignocellulosic feedstock production. In this study, we evaluated selected essential oil crops peppermint (Mentha x piperita L.), ‘Scotch’ spearmint (M. x gracilis Sole), Japanese cornmint (M. canadensis L.), sweet sagewort (Artemisia annua L.), and compared them to switchgrass (Panicum virgatum L.) as lignocellulosic feedstock for ethanol production and for production of high-value natural products. For each crop, the field experiment had a Split-plot Experimental Design nested in year, with 3 blocks, 2 levels of irrigation, and 4 N application rates (0, 60, 120, and 180 kg ha-1. The biomass yields range (in kg ha-1) were 9,500 - 43,430 in Japanese cornmint, 9,300 - 33,870 in peppermint, 7,190 - 33,830 in ‘Scotch’ spearmint, and 11,867 in sweet sagewort, oil content was 0.31 - 0.4% in Japanese cornmint, 0.23 - 0.26% in peppermint, 0.38 to 0.5% in spearmint, and 0,34% in sweet sagewort, and oil yields were (in kg ha-1) 34- 165 in Japanese cornmint, 25 - 108 in peppermint, 29.3 - 126 in spearmint, and 39.7 in sweet sagewort. Treatments affected the concentration of essential oil constituents, however, the oil composition remained within the normal range for the respective species. Estimated ethanol production from the alternative crops were similar to the one from switchgrass. Additional incomes from the essential oil sells would be $1,055 - 5,132 ha-1 from peppermint, $1,309 - 5,580 ha-1 from spearmint, $510 - 2,460 ha-1 from Japanese cornmint, and $3,613 ha-1 from sweet sagewort. The tested species could be used as supplemental crops for biofuel feedstock in irrigated areas. The advantage of the proposed crops over other lignocellulosic species is the production of high-value natural products, which may offset production costs, foster the development of new value-added products, and be more attractive to growers.