• Korean Chemical Engineering Research
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• v.47 no.5
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• pp.620-623
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• 2009

Flavobacterium sp. strain DS5(NRRL B-14859) was used to convert oleic acid to 10-ketostearic acid(10-KSA) via 10-hydroxystearic acid(10-HSA). Increase in cell concentration by centrifuging, collecting cells grown in two flasks, and resuspending in one flask, improved 10-KSA production to 6.5 g/L from 3.5 g/L in a usual flask culture. Tween-80 addition to the culture did not greatly affect the production of 10-KSA and 10-HSA. When culture broth was centrifuged after fermentation, it was observed that pellets were separated into two parts(yellow and white). Gas chromatography analysis showed that 10-KSA and 10-HSA were detected only in a white pellet, suggesting that the bioconversion products of strain DS5 are extracellularly produced and can be easily recovered from cells by a simple centrifugation step.

• KSBB Journal
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• v.24 no.1
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• pp.41-46
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• 2009

Vegetable oils are desirable inexpensive feedstocks for various bioproducts. The content of unsaturated fatty acids such as oleic and linoleic acids are 22% and 55% for soybean oil, 26% and 60% for corn oil, and 61% and 21% for canola oil, respectively. Keto and hydroxy fatty acids are useful industrial chemicals, used in plasticizer, surfactant, lubricant and detergent formulations because of their special chemical properties such as higher viscosity and reactivity compared with other fatty acids. In this study, a microbial isolate, Flavobacterium sp. strain DS5 (NRRL B-14859), was used to convert oleic acid to 10-ketostearic acid (10-KSA) via 10-hydroxystearic acid (10-HSA). Two bioconversion products, 10-KSA and 10-HSA, were quantitatively and qualitatively analyzed using gas chromatography, gas chromatography-mass spectrometry, and $^1H-$ and $^{13}C$-nuclear magnetic resonance. The maximum production of 10-KSA and 10-HSA in flask cultures were 3.4 g/L and 0.5 g/L, respectively. The optimum concentrations of glucose and yeast extract, addition time and volume of oleic acid for 10-KSA production were less than 20 g/L, more than 5 g/L, 18 hand 0.3 ml/50 ml, respectively.