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

Abstract

Agave americana L. is a highly productive, drought-tolerant species being investigated as a feedstock for biofuel production. Some Agave spp. yield crop biomass in semi-arid conditions that are comparable to C 3 and C 4 crops grown in areas with high rainfall. This study evaluates the bioethanol yield potential of A. americana 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 (Miscanthus x giganteus Greef et Deuter, Sorghum bicolor (L.) Moench, and Panicum virgatum L.). Results indicate that (1) WUE does not significantly affect soluble and insoluble (i.e., structural) carbohydrate composition per unit mass in A. americana; (2) without pretreatment, A. americana biomass had the lowest gross heat of combustion, or higher heating/calorific value, compared to high yielding C 4 crops; and (3) after separation of soluble carbohydrates, A. americana 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 A. americana 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.

Five‐year field trial of the biomass productivity and water input response of cactus pear (Opuntia spp.) as a bioenergy feedstock for arid lands

“…in the United States under three different levels of water input. Modeling studies have shown that O. ficus‐indica exhibits higher CO 2 uptake potential across a wider range of maximal daytime temperatures (Owen & Griffiths, 2014) and greater resilience to climate change than Agave tequilana and related Agave spp., which are used for beverage production and show great potential as emerging bioenergy and biomaterials crops (Corbin et al, 2015; Escamilla‐Treviño, 2012; Holtum et al, 2011; Jones et al, 2020; Li et al, 2014; Owen et al, 2016; Yan et al, 2011). Modeling projections for O. ficus‐indica production in Australia (Owen & Griffiths, 2014), North America (Yang et al, 2015), and globally, estimated a maximal productivity of up to 40 Mg DM ha −1 (Owen et al, 2016).…”

“…was suitable for agricultural production in the southwestern USA with significant differences in the response to different water inputs emerging in years 4 and 5 of the study. After 3 years, annual dry matter biomass production rates at comparable planting densities exceeded those observed for Agave americana , a high‐yielding commercial CAM crop (Davis et al, 2017; Jones et al, 2020).…”

Elastic and collapsible: current understanding of cell walls in succulent plants

“…Goycoolea and Cárdenas, 2003 ; Ginestra et al , 2009 ), and Agave (e.g. Li et al , 2014 ; Jones et al , 2020 ). The interest in Aloe vera (L.) Burm.f.…”

Agave and Opuntia Species as Sustainable Feedstocks for Bioenergy and Byproducts

“…The recalcitrance of A. americana was compared with sorghum, switchgrass and miscanthus. Authors reported that A. americana is more easily hydrolyzed by enzymes with greater sugar yield per unit mass [95] and can produce substantial yields of soluble carbohydrates with lower amount of enzymes with the same polysaccharides depolymerization to fermentable monosaccharides than other lignocellulosic feedstocks.…”