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United States Department of Agriculture

Agricultural Research Service

Related Topics

Research Project: Identification, Fractionation, and Isolation of Sorghum Oil and Valuable Functional Lipids Before Or after Fermentation of Grain Sorghum

Location: Sustainable Biofuels and Co-Products

Project Number: 8072-41000-093-05
Project Type: Trust

Start Date: Feb 01, 2014
End Date: Jan 31, 2017

Objective:
The main objectives of the current research project are to investigate the production of and characteristics of sorghum oil that is produced at the back end of a sorghum dry grind ethanol plant. To accomplish these goals, we need to first understand whether the technology developed for back end extraction of corn oil can be used to extract sorghum oil or corn/sorghum oil from feedstock blends. If back end sorghum oil can be economically obtained, we then need to evaluate whether the recent techniques that we have used to increase the yields of back end corn oil can be applied to increase the yields of back end sorghum oil. We also need to conduct experiments to determine the chemical composition of backend sorghum oil. Finally, we need to use the analytical data to understand how back end sorghum oil compares with corn oil, as a suitable a biodiesel feedstock and as a high-value animal feed. A secondary objective will be to investigate the hypothesis that sorghum oil could be removed before fermentation by using decortication or other methods to remove an oil-rich fraction and to then extract the oil using a suitable solvent such as ethanol or to use “green” aqueous enzymatic extraction technology such as we have recently developed to extract corn oil from corn germ that is obtained by prefractionation at the front end of a corn dry grind ethanol plant.

Approach:
We will visit dry grind sorghum ethanol plants identified by USCP leads that are trying to recover back end sorghum oil to collect samples of oil or oil-containing fractions for further processing. We will also begin lab scale experiments on ground sorghum using a lab-scale model system that has been extensively optimized for the corn oil extraction system, and optimize this system for recovery of sorghum oil. This work will use commercially available enzymes and additives that could greatly increase oil yields while simultaneously decreasing water and energy use in the ethanol plant. New enzymes and processes that are successful in increasing oil yields in the lab scale process will be tested in a pilot scale process in the ERRC pilot plants. A detailed economic model of the process will be developed. If successful, scale up at a commercial plant will be proposed. Studies of kernels of several modern sorghum hybrids will be conducted to produce bran, germ, and other fractions, using decortication, scarification, Fitzpatrick Comminuting Mill, sieves, and aspiration. We will investigate the extraction of sorghum oil using ethanol in the same way that we did previously with corn and also investigate the use of a “green” aqueous enzymatic extraction technology such as we have recently developed to extract corn oil from corn germ that is obtained by prefractionation at the front end of a corn dry grind ethanol plant. We previously reported that sorghum oil contains waxes and other compounds that have potential industrial applications. Others reported that sorghum oil contains policosanols that may have nutraceutical applications. We will conduct economic analyses to determine the values of sorghum oils and to estimate the costs of various fractionation and extraction processes.

Last Modified: 10/23/2014
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