ARS | Publication request: AQUEOUS ENZYMATIC EXTRACTION OF CORN OIL FROM CORN GERM

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: April 4, 2005
Publication Date: April 4, 2005
Citation: Moreau, R.A., Powell, M.J., Johnston, D., Hicks, K.B. Aqueous enzymatic extraction of corn oil from corn germ. Meeting Abstract. 96th AOCS Anual Meeting & Expo., Salt Lake City, UT, May 1-5, 2005. Biotechnology Poster 1.

Technical Abstract: ABSTRACT Currently all commercial corn oil is obtained from corn germ by either hexane extraction, or a process that combines pressing/hexane extraction. Because of the safety and environmental issues associated with the use of hexane, the construction and operational costs of hexane extraction facilities are high. Two previous papers were published describing aqueous enzymatic extraction methods for corn oil. This project was undertaken to evaluate and compare these previously-published methods for aqueous enzymatic extraction of corn germ and to develop an improved process using commercially available enzymes that could be used on corn germ derived from dry milling, wet milling, or alternative processes. Using oven dried corn germ from a commercial wet milling facility, we developed a modified aqueous enzymatic method for corn oil extraction with yields of 80 to 90%. Three different commercial cellulases were found to be equally effective. Ten other commercial enzymes were evaluated and resulted in significant, but lower oil yields. When no commercial enzyme was added to the aqueous method, oil yields of 27 to 37% were achieved. No organic solvents are used in this process. The chemical compositions of hexane-extracted and aqueous enzymatic-extracted corn oils were compared and were very similar. Very low levels of free fatty acids were found in the aqueous enzyme extracted oil, indicating that lipolytic activity was minimal. The levels of phytosterols (free and esterified) were slightly lower in the aqueous enzyme extracted oil. Unlike the previous methods which included a "hydrothermal pretreatment" step, heating of the germ was not required. In conclusion, our new aqueous enzymatic extraction process results in oil yields of greater than 90%. Since several commercial cellulase preparations resulted in high yields, we anticipate that some of the new generation of celluloytic enzymes (that are being developed for biomass conversions) may result in even higher oil yields and will likely be more economical than the current generation of cellulolytic enzymes.