Author
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Kuo, Tsung Min |
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Submitted to: Annual Meeting and Expo of the American Oil Chemists' Society
Publication Type: Abstract Only Publication Acceptance Date: 5/9/2003 Publication Date: N/A Citation: N/A Interpretive Summary: Technical Abstract: Mono-oxygenated fatty acids, such as 10-hydroxystearic acid (10-HSA) and 10-ketostearic acid (10-KSA), are useful industrial chemicals with applications in plasticizers, lubricants, coatings, and detergent formulations. Both acids are usually produced in small shake flasks in most microbial conversions of oleic acid. Sphingobacterium thalpophilum (NRRL B-14797) and Bacillus sphaericus (NRRL NRS-732), which solely produce the respective 10-HSA and 10-KSA, serve as two ideal systems for producing these compounds in a scale-up reactor process. Parameters that included medium composition, dissolved oxygen (DO) concentration, impeller agitation speed, cell growth time, and defoamer usage were evaluated in 2-L bench-top reactor vessels. Preliminary results showed that the manganese ion enhanced HSA production by B-14797 and pyruvate enhanced KSA production by NRS-732. Increasing impeller agitation speed and sparger air supply to elevate DO concentration decreased the product yield in both conversion systems. Using a 14-h-old NRS-732 culture grown in 1 L pyruvate-containing PF6 medium, pH 6.5, at 350 rpm agitation speed and about 60% DO, the production of 10-KSA reached 2.5 g/L in 48 h and did not increase thereafter. Using an 8-h-old B-14797 culture grown in 1 L manganese-containing WF3 medium, pH 7.3, at 350 rpm, 20-40% DO, and 400 ppm Biospumex 153K, the production of 10-HSA reached 7 g/L in 4 days. |