A process for the aqueous enzymatic extraction of corn oil from dry-milled corn germ and enzymatic wet milled corn germ (E-Germ)

Authors: Moreau, Robert; Dickey, Leland; Johnston, David; Hicks, Kevin

Submitted to: Journal of the American Oil Chemists' Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/24/2007
Publication Date: 3/20/2009
Citation: Moreau, R.A., Dickey, L.C., Johnston, D., Hicks, K.B. 2009. A process for the aqueous enzymatic extraction of corn oil from dry-milled corn germ and enzymatic wet milled corn germ (E-Germ). Journal of the American Oil Chemists' Society 86:p.469-474.

Interpretive Summary: Previously, we reported an aqueous enzymatic oil extraction process that achieved oil yields of 80-90% using corn germ from a commercial corn wet mill. Three commercial cellulases were reported to result in similar oil yields when wet milled corn germ was used as a feedstock in this process. When the same process was evaluated using either corn germ from a commercial corn dry mill or corn germ from a pilot scale enzymatic wet milling process (E-Germ), no oil was obtained. In the current study, a commercial protease was identified which, when incorporated into the previous protocol, was demonstrated to achieve oil yields of about 50% from dry milled corn germ and oil yields of 90% from E-Germ. With this modification, it is now possible to obtain corn oil from dry milled corn germ and E-Germ using two common commercial enzymes, without the use of hazardous solvents. We anticipate that this process could be used on a small scale to produce a new valuable co-product, corn oil, at a dry grind ethanol plant which is equipped to remove corn germ before fermentation.

Technical Abstract: Previously, we reported an aqueous enzymatic oil extraction process that achieved oil yields of 80-90% using corn germ from a commercial corn wet mill. Three commercial cellulases were reported to result in similar oil yields when wet milles corn germ was used as a feedstock in this process. When the same process was evaluated using either corn germ from a commercial corn dry mill or corn germ from a pilot scale enzymatic wet milling process (E-Germ), no oil was obtained. In the current study, a commercial protease was identified which, when incorporated into the previous protocol, was demonstrated to achieve oil yields of about 50% from dry milled corn germ and oil yields of 90% from E-Germ.