Farm-Scale Harvest and Storage Techniques of Sweet Sorghum for Better Ethanol Production

A major  constraint for sweet sorghum (Sorghum bicolor L. Moench) as a reliable biofuel feedstock is the fast biomass degradation due to its high soluble sugar content. An efficient way to overcome this could be an on-farm storing system of undistilled ethanol from sweet sorghum juice, while the remaining bagasse could be ensiled for complementary energy generation. Andrea Monti of the University of Bologna in Italy evaluated different harvest methods and storage techniques to develop an efficient on-farm processing system to store sweet sorghum biomass.

Harvesting during the hard dough stage and defoliating the plants before juice extraction resulted in higher ethanol yield. The use of commercially available fructophilic yeasts maximized undistilled ethanol yield and increased on-farm storing to about 1 year. The residual bagasse was ensiled and inoculated with Lactobacillus commonly used in forage conservation which significantly improved its quality as feedstock for biogas fermenters.