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Title: CONVERSION OF FATTY ACIDS BY BACILLUS SPHAERICUS-LIKE ORGANISMS

Author
item Kuo, Tsung Min
item NAKAMURA, LAWRENCE - USDA-ARS, RETIRED
item Lanser, Alan

Submitted to: Current Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/17/2002
Publication Date: 10/1/2002
Citation: KUO, T., NAKAMURA, L.K., LANSER, A.C. CONVERSION OF FATTY ACIDS BY BACILLUS SPHAERICUS-LIKE ORGANISMS. CURRENT MICROBIOLOGY. 2002. V. 45. P. 265-271.

Interpretive Summary: The U.S. agriculture industry sustains a huge surplus of vegetable oils, especially soybean oil. These oils represent attractive renewable resources for the production of useful chemicals. We are investigating effective "green" bioprocesses that can convert vegetable oils and their component fatty acids to value-added industrial products. In this study, we characterized a group of bacteria known for their ability to control mosquitoes. We found some strains could also modify a common fatty acid of soybean oil to form a new product determined to be a keto-fatty acid. The reaction was optimized and applied to a bioreactor process to obtain large quantities of the compound. Since keto-fatty acids are industrial chemicals used in plasticizer, lubricant, and detergent formulations, the findings provide opportunities for industrial development of large-scale production of these compounds.

Technical Abstract: Bacillus sphaericus species are mesophilic round-spored organisms that readily utilize fatty acid-based surfactants during growth but their ability to modify fatty acids is unknown. Among 57 B. sphaericus-like strains tested for fatty acid transformation activity in Wallen fermentation (WF) medium, ten converted oleic acid to a new product determined by GC/MS to be 10-ketostearic acid (10-KSA). Additionally, a few other strains converted ricinoleic acid and linoleic acid to new products that remain to be characterized. Unlike most microbial hydrations of oleic acid, which produce a mixture of 10-KSA and 10-hydroxystearic acid, the conversion of oleic acid by B. sphaericus strains was unique in that 10-KSA was the sole reaction product. By replacing dextrose with sodium pyruvate in WF and adjusting to pH 6.5, conversion of oleic acid to 10-KSA by strain NRRL NRS-732 was improved from about 11% to greater than 60%. Using the defined optimal conditions, the conversion reaction was scaled up in a stirred-batch reactor using technical-grade oleic acid as substrate. This is the first report on the characterization of fatty acid conversions by B. sphaericus species.