Fermentation Inhibition of Forage and Sweet Sorghum Silages Treated with Acrylic or Maleic Acid1
- N. S. Hill,
- G. L. Posler and
- K. K. Bolsen2
One source of biomass for conversion to liquid fuel is sweet sorghum [Sorghum bicolor (L.) Moench]. Its potential use as an alcohol feedstock is limited by a harvesting season too short to supply batch fermenters with a constant source of substrate. One solution is to conserve sugars by ensiling the crop with fermentation inhibitors. ‘Rio’, ‘Dale’ and DeKalb ‘FS25A’ sorghums were harvested at physiological maturity and treated with 2.5 or 5.0 g of acrylic or maleic acid per kilogram of herbage. Treated herbage was analyzed for glucose, fructose, sucrose, dry matter, and protein concentration. After 130 days fermentation, silages were analyzed for these factors plus ammonia, lactic acid, and volatile fatty acids. Dale and FS25A herbage had proportionately higher sugar monomers and lower total sugar conservation than Rio. Sugar recovery increased from less than 100 g kg−1 to 987 g kg−1 with acrylic acid application but was unaffected by maleic acid. Both acid treatments decreased lactic and acetic acid production, while silages treated with acrylic acid had higher ammonia and propionic and valeric acid production, and pH. Ammonia production decreased in silages receiving maleic acid. These data indicate that sweet sorghum treated with acrylic acid can be stored as silage without appreciable sugar loss.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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