Conversion of fatty acids by Bacillus sphaericus-like organisms.
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 gas chromatography - mass spectrometry (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 more than 60%. Using the defined optimal conditions, the conversion reaction was scaled up in a stirred-batch reactor by using technical-grade oleic acid as substrate. This is the first report on the characterization of fatty acid conversions by B. sphaericus species.
Microbial Genomics and Bioprocessing Research Unit, National Center for Agricultural Utilization Research, Agricultural Research Service, U.S. Department of Agriculture, 1815 North University Street, Peoria, IL 61604, USA. kuotm@mail.ncaur.usda.gov
Tsung Min
TM
Kuo
Lawrence K
LK
Nakamura
Alan C
AC
Lanser
D001407:Bacillus / Q000378:metabolism*; D003470:Culture Media; D005227:Fatty Acids / Q000145:classification / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D019787:Linoleic Acid / Q000378:metabolism; D019301:Oleic Acid / Q000378:metabolism; D012277:Ricinoleic Acids / Q000378:metabolism; D013229:Stearic Acids / Q000378:metabolism; D013997:Time Factors
C403718:10-ketostearic acid; D003470:Culture Media; D005227:Fatty Acids; D012277:Ricinoleic Acids; D013229:Stearic Acids; D019301:Oleic Acid; D019787:Linoleic Acid; C030521:ricinoleic acid