Page Banner

United States Department of Agriculture

Agricultural Research Service

Title: Solid State Fermentation of Sorghum Hybrids Varying in Extractable Sugars

Authors
item Philipp, Dirk - IA STATE UNIVERSITY
item Moore, Kenneth - IA STATE UNIVERSITY
item Pedersen, Jeffrey
item Grant, Richard - W H AG RES INSTITUTE
item Redfearn, Daren - OK STATE UNIVERSITY
item Mitchell, Robert

Submitted to: Biomass and Bioenergy
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 7, 2007
Publication Date: July 1, 2007
Citation: Philipp, D., Moore, K.J., Pedersen, J.F., Grant, R.J., Redfearn, D.D., Mitchell, R. 2007. Solid state fermentation of sorghum hybrids varying in extractable sugars. Biomass and Bioenergy 31:492-496.

Interpretive Summary: Use of biomass as feedstock for bio-energy production requires novel methods of storage in order to optimize use by industry. A storage method commonly used for livestock feeds, ensiling, may provide a source of organic chemicals as well as fiber for industrial use while reducing the risks associated with current dry-storage procedures. Sorghum has been used widely to produce ethanol. We compared the chemical makeup and fermentation of six sorghum hybrids following 1, 7, and 21 days of ensiling. Neutral detergent fiber, acid detergent fiber, and acid detergent lignin content ranged from 38 to 50%, 25 to 34%, and 4 to 6% among hybrids. Hemicellulose and cellulose ranged from 13 to 19% and 20 and 28%. Total non-structural carbohydrates and water soluble carbohydrates varied among hybrids from 18 to 32% and 5 to 20%. Lactic acid and pH declined further after day 7 indicating that the ensiling process continued until at least 21 days. Acetic acid, propionic acid, and ammonia increased between 1 and 7 days of ensiling but did not change until the end of the ensiling period. Total organic acids averaged 2.5% after day 1 and increased to 4.2 and 4.7% after days 7 and 21 respectively. Our results suggest that significant genotypic variation in sorghum offers the potential of designing dual-purpose hybrids for production of biomass and economically valuable byproducts such as organic acids.

Technical Abstract: Renewable feedstock resources require novel storage technologies to optimize industrial use. Solid state fermentation of biomass feedstock may provide organic chemicals and fibers while reducing the risk of current dry-storage procedures. Sorghum [Sorghum bicolor (L.) Moench] has been used widely to produce ethanol. Here, we compare the chemical composition and fermentation of six sorghum hybrids following 1, 7, and 21 days of ensiling. Neutral detergent fiber, acid detergent fiber, and acid detergent lignin content ranged from 38 to 50%, 25 to 34%, and 4 to 6% among hybrids, respectively. Hemicellulose and cellulose ranged from 13 to 19% and 20 and 28%, respectively. Total non-structural carbohydrates and water soluble carbohydrates varied among hybrids from 18 to 32% and 5 to 20%, respectively. Acetic acid, propionic acid, and ammonia increased between 1 and 7 days of ensiling but did not change until the end of the ensiling period. Lactic acid and pH declined further after day 7 and were lower after 21 days than either at day 1 or 7. Total organic acids averaged 2.5% after day 1 and increased to 4.2 and 4.7% after days 7 and 21, respectively. Our results suggest that genotypic variation in sorghum offers the potential of designing dual-purpose hybrids for production of biomass and economically valuable byproducts such as organic acids.

Last Modified: 4/18/2014
Footer Content Back to Top of Page