Submitted to: Biotechnology Letters
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 29, 2002
Publication Date: January 1, 2003
Citation: KUO, T., RAY, K.J., MANTHEY, L.K. A FACILE REACTOR PROCESS FOR PRODUCING 7,10-DIHYDROXY-8(E)-OCTADECENOIC ACID FROM OLEIC ACID CONVERSION BY PSEUDOMONAS AERUGINOSA PR3. BIOTECHNOLOGY LETTERS. 2003. V.25. P. 29-33. Interpretive Summary: U.S. soybean oil production has a large annual surplus of more than 1.2 billion pounds. Converting this surplus into new, value-added products would greatly benefit U.S. farmers and the agricultural industry. At the National Center for Agricultural Utilization Research we have examined a number of microbial systems for the conversion of fatty acids found in soybean oil to new products with enhanced functionality. One important reaction involves a bacterial strain PR3, which in small shake flasks converts inexpensive oleic acid, a component of soybean oil, to a novel compound simply called DOD [7,10-dihydroxy-8(E)-octadecenoic acid]. In this study we evaluated factors that would greatly influence the bioconversion reaction in a scaled-up reactor process for DOD production and developed a simple, effective downstream processing procedure for obtaining DOD crystals. The newly developed process technology not only provides DOD to researchers in hundred-gram quantities for testing new industrial uses, but also serves as a platform for producing other value-added bioproducts derived from vegetable oils and their component fatty acids.
Technical Abstract: Pseudomonas aeruginosa strain PR3 (NRRL B-18602) converts oleic acid to a novel compound, 7,10-dihydroxy-8(E)-octadecenoic acid (DOD). The bioconversion was scaled up in a 7-L bench-top, stirred-batch reactor to provide DOD for testing of potential industrial uses. Aeration was supplied continuously from the top through two ports on the headplate and periodically through a bottom sparger, in conjunction with the use of marine impellers for agitation. This unique aeration arrangement maintained the dissolved oxygen concentration in the 40-60% range during the maximal bioconversion and it also avoided excessive medium foaming during the reaction. Furthermore, the level of dissolved oxygen in the first 24 h of reaction played an important role in the initial rate of DOD production. DOD production reached a plateau after 72 h with a yield up to 100 g (or 50% recovery) from a total of 9 L of medium from two reactors run simultaneously. The reaction culture medium was processed using newly adapted procedures in the pilot plant that included crystallization of DOD from ethyl acetate solution at -15 degrees C. The newly developed bioprocess will serve as a platform for the scale-up production of other value-added products derived form vegetable oils and their component fatty acids.