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United States Department of Agriculture

Agricultural Research Service

Title: Conversion of Oleic Acid to 7,10-Dihydroxy-8(e)-Octadecenoic Acid by Pseudomonas Sp. Pr3 in a Reactor - Practical Considerations

Authors
item Kuo, Tsung Min
item Ray, Karen
item Manthey, Linda

Submitted to: Annual Meeting and Expo of the American Oil Chemists' Society
Publication Type: Abstract Only
Publication Acceptance Date: May 8, 2002
Publication Date: N/A

Technical Abstract: Pseudomonas aeruginosa strain PR3 (NRRL B-18602) converts oleic acid to a novel compound, 7,10-dihydroxy-8(E)-octadecenoic acid (DOD). In order to produce DOD in sufficient quantity for testing potential industrial applications, the bioconversion was scaled-up in a 7-L bench-top, stirred- batch reactor using technical-grade oleic acid as substrate. Aeration was supplied continuously from the top through two ports on the headplate at 220 mL/min as well as through a bottom sparger at 15 mL/min for 15 min in each hour. This aeration arrangement, in conjunction with the use of a marine impeller for agitation, maintained the dissolved oxygen concentration in the 40-60% range and also avoided excessive medium foaming during the conversion reaction. A time course of bioconversion indicated that DOD production at 28 degree C steadily increased for the first 48 h and reached a plateau after 96-120 h. The level of dissolved oxygen in the first 24 h of reaction played an important role in the initial rate and the maximum level of DOD production. Using an 8-h-old culture grown in 4.5 L SM6 medium, pH 7.2 at 650 rpm agitation speed, DOD production was reached at over 10 g/L (a>45% yield). The crude extract obtained from a total of 9 L reaction culture in two reactors run simultaneously was processed in a pilot plant and DOD was crystallized from ethyl acetate at-15 degree C. DOD in hundred-gram quantity is available for testing industrial applications. 

Last Modified: 7/31/2014
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