TITLE:
Juice, Ethanol, and Grain Yield Potential of Five Sweet Sorghum (Sorghum bicolor [L.] Moench) Cultivars
AUTHORS:
Laban K. Rutto, Yixiang Xu, Michael Brandt, Shuxin Ren, Maru K. Kering
KEYWORDS:
Sweet Sorghum; Cultivar; Biomass; Juice and Grain Yield; Ethanol Yield Potential
JOURNAL NAME:
Journal of Sustainable Bioenergy Systems,
Vol.3 No.2,
June
25,
2013
ABSTRACT:
Sweet sorghum (Sorghum bicolor [L.] Moench) accumulates fermentable sugars in the stem and is increasingly being studied as a potential source of feedstock for bioethanol production. The objective of this study was to evaluate biomass and grain yield in five sweet sorghum cultivars (Dale, M81E, Sugar Drip, Della and Keller) and to determine quality of extractable juice and grain. Randomized complete block experiments were performed in the summer of 2009, 2010, and 2011. Leaf dry weight varied with year and cultivar and averaged 6177 kg·ha-1. Fresh stem weight ranged from 21 to 54 Mg·ha-1 with a mean across years and cultivars of 32.9 Mg·ha-1. Variations in stem weight were correlated with extractable juice volumes that ranged from 10 to 24 m3·ha-1. Juice Brix values fell within a narrow range (14% - 19%) across years and cultivars with an average of 15.6%. In all production years, theoretical sugar and ethanol yield were always numerically higher for Keller and M81E. Grain yield was lowest in Keller (90 kg·ha-1), but ranged from 400 to 1300 kg·ha-1 in other cultivars with a mean of 584 kg·ha-1 across years. However, Keller had the highest starch content with a lower proportion of resistant starch in the grain. Except for Keller, the cultivars tested are potential sources of both fermentable sugars and grain.