Ethanol production potential of sweet sorghum assessed using forage fiber analysis procedures

Abstract

Sweet sorghum (Sorghum bicolor (L.) Moench) is widely recognized as a highly promising biomass energy crop with particular potential to complement sugarcane production in diversified cropping systems. Agronomic assessments have led to identification of four cultivars well suited for such sugarcane-based production systems in southern Louisiana. Sweet sorghum biofuel production systems are currently being developed, and research producing large sample numbers requiring ethanol yield assessment is anticipated. Fiber analysis approaches developed for forage evaluation appear to be useful for screening such large numbers of samples for relative ethanol yield. Chemical composition, forage fiber characteristics, digestibility, and ethanol production of sweet sorghum bagasse from the four cultivars were assessed. Measures of detergent fiber, lignin, and digestibility were highly correlated with ethanol production (P < 0.01). The best linear regression models accounted for about 80% of the variation among cultivars in ethanol production. Bagasse from the cultivar Dale produced more ethanol per gram of material than any of the other cultivars. This superior ethanol production was apparently associated with less lignin in stems of Dale. Forage evaluation measures including detergent fiber analyses, in vitro digestibility, and an in vitro gas production technique successfully identified the cultivar superior in ethanol yield indicating their usefulness for screening sweet sorghum samples for potential ethanol production in research programs generating large sample numbers from evaluations of germ plasm or agronomic treatments. These screening procedures reduce time and expense of alternatives such as hexose sugar assessment for calculating theoretical ethanol yield.

Environment Has Little Effect on Biomass Biochemical Composition of Miscanthus × giganteus Across Soil Types, Nitrogen Fertilization, and Times of Harvest

“…In theory, the lower the lignin content in biomass, the better. However, lignin is a cross-linked polymer that is essential in providing structural support, limiting pest damage, and allowing xylem vessels to function under the high tensions that develop during transpiration [21,25,43].…”

Selection Signatures in Four Lignin Genes from Switchgrass Populations Divergently Selected for In Vitro Dry Matter Digestibility

“…Reducing recalcitrance of switchgrass biomass to fermentation has been a long-term research objective toward improving the economics and sustainability of livestock production [45]. Parallels between ruminant livestock fermentation and biomass fermentation for bioethanol suggest similar mechanisms for biomass recalcitrance [12, 46]. The divergent populations generated from recurrent selected for IVDMD [31] provided powerful tools to identify the polymorphisms under selection and the candidate polymorphisms associated with lignin concentration and ethanol yield.…”

Biomass and Sugar Content of Some Varieties of Sorghum (Sorghum Bicolor L. Moench) on Dry Land Forest as Feedstock Bioethanol

“…The production costs of biofuel from sweet sorghum are cheaper than that from sugarcane in the USA [11]. Ethanol production is determined by the production of biomass and sugar content in stem [12,10]. Among the parts of the sorghum, stems give contributed most to produce juice as bioethanol feedstock.…”