Composition of sugar cane, energy cane, and sweet sorghum suitable for ethanol production at Louisiana sugar mills

Abstract

A challenge facing the biofuel industry is to develop an economically viable and sustainable biorefinery. The existing potential biorefineries in Louisiana, raw sugar mills, operate only 3months of the year. For year-round operation, they must adopt other feedstocks, besides sugar cane, as supplemental feedstocks. Energy cane and sweet sorghum have different harvest times, but can be processed for bio-ethanol using the same equipment. Juice of energy cane contains 9.8% fermentable sugars and that of sweet sorghum, 11.8%. Chemical composition of sugar cane bagasse was determined to be 42% cellulose, 25% hemicellulose, and 20% lignin, and that of energy cane was 43% cellulose, 24% hemicellulose, and 22% lignin. Sweet sorghum was 45% cellulose, 27% hemicellulose, and 21% lignin. Theoretical ethanol yields would be 3,609kg per ha from sugar cane, 12,938kg per ha from energy cane, and 5,804kg per ha from sweet sorghum.