SIMULTANEOUS ENSILING AND ENZYMATIC-HYDROLYSIS OF STRUCTURAL POLYSACCHARIDES

Sweet sorghum is an attractive fermentation feedstock because as much as 40% of the dry weight consists of the readily fermentable sugars sucrose, glucose, and fructose. However, if this material is to serve as year-round feedstock, some means must be employed to stabilize its sugar content following harvest. Work presented here has demonstrated that a modified version of the traditional ensiling process is effective in accomplishing this objective. The modified ensiling process is conducted in the presence of cellulolytic and hemicellulolytic enzymes. Significant amounts of cellulose and hemicellulose are degraded; the amounts are proportional to enzyme loading. The heterolactic fermentation of the ensiling organisms is complete in approximately four days. Hydrolysis of polysaccharides and the accumulation of glucose follows power law kinetics and is essentially complete in 30 days. This method of carbohydrate storage becomes effective using cellulase enzyme loadings as low as five International Filter Paper Units/g DM of sweet sorghum.