The Potential of Ethanol Production from Sweet Sorghum in Sub-Saharan Africa as Affected by Variety and Sowing Time

Abstract

Renewable bio-energy is receiving worldwide importance in view of depleting fossil energy. Research works on sorghum as bio-fuel crop in sub-Saharan Africa are meager. The study aimed to investigate the potential of sweet sorghum for ethanol production from stem-juice. The experiment was conducted in Sudan, Khartoum State, during 2016-2017. Forty local and exotic sweet sorghum varieties arranged in RCB Design were investigated under irrigated conditions across three sowing times. Yields of cane, juice, sugar, ethanol and related attributes were studied. Highly significant differences (P=.01) were detected among varieties and interaction with sowing time. Ethanol yield potentials for some varieties were comparable to those reported in India and USA (1162-1416 L ha-1). High brix values (20-22%) and cane yields (45-51 ha-1) were encountered. Juice yield was low (3673-13743 L ha-1) probably due to reduced milling efficiency. The exotic materials performed better than the local ones in theoretical ethanol productivity and related attributes other than cane yield. Eight exotic and five local varieties were recommended for ethanol production. None of the Ankolib materials appeared to have notable potential for ethanol production. Interaction of sowing time with variety has great impact on ethanol yield implying the importance of variety option for different sowing times. It was concluded that the study furnished basic data needed for assessing the economic feasibility of ethanol production from irrigated sweet sorghum in sub-Saharan Africa-Sudan.