A new microbial isolate (Bacillus cereus 50) transformed 12-hydroxyoctadecanoic acid to 12-hydroxyoctadecanamide when grown aerobically in 1% yeast extract medium at 30°C, shaken at 250 rpm for 2 to 5 d. The compound was purified by thin-layer chromatography and characterized by infrared, gas chromatography, mass spectrometry, and nuclear magnetic resonance. The yields of 12-hydroxyoctadecanamide were 9.1 and 21.5% after 2 and 5 d, respectively. JAOCS 74, 601-603 (1997).Fatty amides have diverse applications as chemical additives, lubricants, slip agents, and nonsticky and protective coatings (1). Fatty amides, such as erucamide, are chemically synthesized from 13(Z)-docosenoic acid (erucic acid) (2,3). Microbial transformation of 9(Z)-octadecenoic acid to 9(Z)-octadecenamide (6% yield on total lipids extracted) by Bacillus cereus B-14812 (4), and to 9(Z)-octadecenamide, hexadecenamide, tetradecenamide, and tetradecanamide by B. megaterium B-3437 (5-7% yield on total lipids extracted) (5) has been reported.During our continuing efforts to isolate new microorganisms for biotransformation of 12-hydroxyoctadecanoic acid (HOA) (6,7), we discovered another active strain of B. cereus 50 (8). Bacillus cereus 50 produced significant amounts of 12-hydroxyoctadecanamide (12-HOAM) when grown aerobically in 1% yeast extract (1% YE) that contained 0.2% (wt/vol) of 12-HOA at 30°C when shaken at 250 rpm. In this paper, we report the conversion of 12-HOAM from 12-HOA after 2 and 5 d, and its isolation and identification by infrared (IR), gas chromatography-mass spectrometry (GC-MS), positive chemical ionization-mass spectrometry (PCI-MS), and nuclear magnetic resonance (NMR).
EXPERIMENTAL PROCEDURESMaterials. All chemicals and solvents were of ACS grade obtained from commercial sources. The acids, R-(+)-12-HOA and hexadecanoic acid (palmitic acid), were obtained from Sigma (St. Louis, MO) with purities greater than 98% by GC analysis. The product, 12-hydroxyoctadecanamide, was purified to better than 97% purity, as determined by GC analysis. YE was from Difco Laboratories (Detroit, MI).Microorganisms and microbial conversion study. Strain 50 was isolated from the intestinal tract of a fish (large mouth bass, Micropterus salmoides) (8). A single colony was cultured in 5 mL of tryptone medium (containing 0.5% tryptone, 0.2% KH 2 PO 4 , 0.4% Na 2 HPO 4 , 0.2% (NH 4 ) 2 SO 4 , 0.01% CaCl 2 ·H 2 O and 0.001% FeSO 4 ·7H 2 O, pH 7.2) at 30°C, 200 rpm for 18 h. The following day, 2-mL cultures were added to 100 mL of 1% YE medium (containing 1% yeast extract, 0.2% KH 2 PO 4 , 0.4% Na 2 HPO 4 , 0.2% (NH 4 ) 2 SO 4 , 0.01% CaCl 2 ·H 2 O and 0.001% FeSO 4 ·7H 2 O, pH 7.2). Ten mL of the 1-to-50 diluted culture was transferred to each of the 125-mL capacity Erlenmeyer flasks, and 12-HOA was added to a final concentration of 0.2% to carry out the bioconversion reaction for up to 5 d. Pure dilution culture served as control. Triplicate samples were used.Three flasks (10 mL/flask) were removed on day 2 and on day 5. The entire contents of trip...