AUTHOR=Jones Alexander M. , Zhou Yadi , Held Michael A. , Davis Sarah C. 

TITLE=Tissue Composition of Agave americana L. Yields Greater Carbohydrates From Enzymatic Hydrolysis Than Advanced Bioenergy Crops

JOURNAL=Frontiers in Plant Science

VOLUME=11

YEAR=2020

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2020.00654

DOI=10.3389/fpls.2020.00654

ISSN=1664-462X

ABSTRACT=<p><italic>Agave americana</italic> L. is a highly productive, drought-tolerant species being investigated as a feedstock for biofuel production. Some <italic>Agave</italic> spp. yield crop biomass in semi-arid conditions that are comparable to C<sub>3</sub> and C<sub>4</sub> crops grown in areas with high rainfall. This study evaluates the bioethanol yield potential of <italic>A. americana</italic> by (1) examining the relationship between water use efficiency (WUE) and plant carbohydrates, (2) quantifying the carbohydrate and energy content of the plant tissue, and (3) comparing the products of enzymatic hydrolysis to that of other candidate feedstocks (<italic>Miscanthus x giganteus</italic> Greef et Deuter, <italic>Sorghum bicolor</italic> (L.) Moench, and <italic>Panicum virgatum</italic> L.). Results indicate that (1) WUE does not significantly affect soluble and insoluble (i.e., structural) carbohydrate composition per unit mass in <italic>A. americana</italic>; (2) without pretreatment, <italic>A. americana</italic> biomass had the lowest gross heat of combustion, or higher heating/calorific value, compared to high yielding C<sub>4</sub> crops; and (3) after separation of soluble carbohydrates, <italic>A. americana</italic> cellulosic biomass was most easily hydrolyzed by enzymes with greater sugar yield per unit mass compared to the other biomass feedstocks. These results indicate that <italic>A. americana</italic> can produce substantial yields of soluble carbohydrates with minimal water inputs required for cultivation, and fiber portions of the crop can be readily deconstructed by cellulolytic enzymes for subsequent biochemical fermentation.</p>