Microbial conversion of linoleic and linolenic acids to unsaturated hydroxy fatty acids

The conversion of oleic acid to 10-hydroxystearic acid with resting cells ofNocardia cholesterolicum (NRRL 5767) has been previously reported. These same microorganisms also convert linoleic and linolenic acids to 10-hydroxy-12c-octadecenoic and 10-hydroxy-12c,15c-octadecadienoic acids, respectively. The reaction occurs best at 35°C and a pH of 6.5. Under optimum conditions, 75–80% of the unsaturated fatty acid substrate is converted to the corresponding hydroxy acid. The hydroxy products were characterized by gas chromatography, gas chromatographymass spectrometry, nuclear magnetic resonance (NMR) and infrared (IR) spectroscopy. Other microorganisms that successfully converted these substrates include another strain ofNocardia cholesterolicum (NRRL 5768) andNocardia sp. (NRRL 5636). Presented at the 82nd Annual meeting of the American Oil Chemists’ Society, Chicago, IL, May 12–15, 1991.     

Stereospecific hydration of unsaturated fatty acids by bacteria

Three new 10-hydroxy fatty acids, all optically active, have been prepared by the anaerobic microbiological hydration of acis-9 double bond. Substrates that formed these new hydroxy fatty acids are linoleic, linolenic, and ricinoleic acids. The hydroxyl group has the D configuration and the methyl esters are levorotatory. Infrared, mass spectral, specific rotation and ultraviolet data on these compounds were determined. There was no migration of the unreated double bonds at C₁₂ and C₁₅ in linoleic or linolenic acids. The presence of a double bond in the 10-hydroxy fatty acids significantly increased the optical rotation of the methyl esters. The hydratase enzyme showed unusual specificity among Δ⁹ unsaturated acids. While it hydrates methylene interrupted and hydroxy unsaturated acids, it failed to hydrate either 9-decenoic, 12,13-epoxy- or 12-keto-cis-9-octadecenoic acids or sterculic acid. Presented at the AOCS Meeting, San Francisco, April 1969. No. Marketing and Nutrition Res. Div., ARS, USDA.     

Structure-activity relationship of unsaturated fatty acids as mosquito ovipositional repellents

Various straight-chain unsaturated fatty acids from C₁₄ to C₂₄ were evaluated for their ovipositional repellency against gravid females of the southern house mosquitoCulex quinquefasciatus Say, and the relationship between the structures of the fatty acids and their ovipositional repellency was determined. A double bond withZ configuration was prerequisite for an unsaturated fatty acid to be highly repellent;E isomers were less active or even inactive. No relationship was found between the repellency and the number of double bonds in the unsaturated fatty acids. In C₁₈ monounsaturated fatty acids, (Z)-9 acid was more active than (Z)-11 and (Z)-6 acids, indicating that a double bond at the 9 position rendered an acid highly repellent. Among (Z)-9-alkenoic acids of different chain lengths, the most repellent was C₁₈ acid which was also more active than (Z)-11-C₂₀, (Z)-13-C₂₂, and (Z)-15-C₂₄ acids. Oleic[(Z)-9-octadecenoic]acid, which met all these criteria, was the most ovipositionally repellent among the unsaturated fatty acids tested.Diptera: Culicidae.     

Conversion of linoleic acid to 10-hydroxy-12(Z)-octadecenoic acid byFlavobacterium sp. (NRRL B-14859)

A new microbial isolate,Flavobacterium sp. strain DS5, converts linoleic acid into 10-hydroxy-12(Z)-octadecenoic acid (10-HOA) with 55% yield. The product was characterized by gas chromatography (GC), GC/mass spectrometry, nuclear magnetic resonance and Fourier transform infrared spectroscopy. The specific optical rotation of 10-HOA is [α] _D ²⁴ =−5.58 (methanol). The optimum time, pH and temperature for the production of 10-HOA were 36h, 7.5 and 20–35°C, respectively. The enzyme(s) that converts linoleic acid to 10-HOA is soluble and located intracellulary in strain DS5. Two minor products, 10-methoxy-12-octade-cenoic acid and 10-keto-12-octadecenoic acid, were also identified. 10-HOA was further metabolized by strain DS5. Among the unsaturated fatty acids studied, the order of reactivity for the DS5 enzyme(s) is oleic>palmitoleic> linoleic>linolenic>γ-linolenic>myristoleic acid.     

Production of 3R-hydroxy-polyenoic fatty acids by the yeast Dipodascopsis uninucleata

Various fatty acids were fed to the yeast Dipodascopsis uninucleata UOFS Y 128, and the extracted samples were analyzed for the accumulation of 3-hydroxy metabolites with the help of electron impact gas chromatography-mass spectrometry. Fatty acids containing a 5Z,8Z-diene system (5Z,8Z,11Z-eicosatrienoic, 5Z,8Z,11Z,14Z-eicosatetraenoic, and 5Z,8Z,11Z,14Z,17Z-eicosapentaenoic acids) yielded the corresponding 3-hydroxy-all-Z-eicosapolyenoic acids. Moreover, linoleic acid (9Z,12Z-octadecadienoic acid) and 11Z,14Z,17Z-eicosatrienoic acid were converted to the 3-hydroxylated metabolites of shorter chain length, e.g., 3-hydroxy-5Z,8Z-tetradecadienoic acid and 3-hydroxy-5Z,8Z,11Z-tetradecatrienoic acid, respectively. In contrast, no accumulation of a 3-hydroxy metabolite was observed with oleic acid (9Z-octadecenoic acid), linolelaidic acid (9E,12E-octadecadienoic acid), γ-linolenic acid (6Z,9Z,12Z-octadecatrienoic acid), and eicosanoic acid as substrate. These findings pinpoint that the 3-hydroxylation of a fatty acid in Dipodascopsis uninucleata requires a 5Z,8Z-diene system either directly or following initial incomplete β-oxidation. Following analysis of the enantiomer composition, the arachidonic acid metabolite was identified as 3R-hydroxy-5Z,8Z,11Z,14Z-eicosatetraenoic acid, which rules out a normal β-oxidation as biosynthetic route to this new class of oxylipins.     

Production of polyhydroxy fatty acids from linoleic acid by Clavibacter sp. ALA2

Hydroxy fatty acids are important industrial materials. We isolated a microbial culture, Clavibacter sp. ALA2, which converts linoleic acid to many polyhydroxy fatty acids. Structures of the products were determined as: 12,13,17-trihydroxy-9(Z)-octadecenoic (THOA, main product), 12-[5-ethyl-2-tetrahydrofuranyl]-7,12-dihydroxy-9(Z)-dodecenoic (ETDDA), and 12-[5-ethyl-2-tetrahydrofuranyl]-12-hydroxy-9(Z)-dodecenoic (ETHDA) acid. The yield of THOA was 25% and the relative amount of the products were THOA/ETDDA/ETHDA =9:1.3:1. The structures of the hydroxy unsaturated fatty acids resemble those of plant self-defense substances.     

A pathway for biosynthesis of divinyl ether fatty acids in green leaves

[1-¹⁴C]α-Linolenic acid was incubated with a particulate fraction of homogenate of leaves of the meadow buttercup (Ranunculus acris L.). The main product was a divinyl ether fatty acid, which was identified as 12-[1′(Z),3′(Z)-hexadienyloxy]-9(Z), 11(E)-dodecadienoic acid. Addition of glutathione peroxidase and reduced glutathione to incubations of α-linolenic acid almost completely suppressed formation of the divinyl ether acid and resulted in the appearance of 13(S)-hydroxy-9(Z), 11(E), 15(Z)-octadecatrienoic acid as the main product. This result, together with the finding that 13(S)-hydroperoxy-9(Z), 11(E), 15(Z)-octadecatrienoic acid served as an efficient precursor of the divinyl ether fatty acid, indicated that divinyl ether biosynthesis in leaves of R. acris occurred by a two-step pathway involving an ω6-lipoxygenase and a divinyl ether synthase. Incubations of isomeric hydroperoxides derived from α-linolenic and linoleic acids with the enzyme preparation from R. acris showed that 13(S)-hydroperoxy-9(Z), 11(E)-octadecadienoic acid was transformed into the divinyl ether 12-[1′(Z)-hexenyloxy]-9(Z), 11(E)-dodecadienoic acid. In contrast, neither the 9(S)-hydroperoxides of linoleic or α-linolenic acids nor the 13(R)-hydroperoxide of α-linolenic acid served as precursors of divinyl ethers.     

New cyclopentenone fatty acids formed from linoleic and linolenic acids in potato

[1-¹⁴C]Linoleic acid was incubated with a whole homogenate preparation from potato stolons. The reaction product contained four major labeled compounds, i.e., the α-ketol 9-hydroxy-10-oxo-12(Z)-octadecenoic acid (59%), the epoxy alcohol 10(S),11(S)-epoxy-9(S)-hydroxy-12(Z)-octadecenoic acid (19%), the divinyl ether colneleic acid (3%), and a new cyclopentenone (13%). The structure of the last-mentioned compound was determined by chemical and spectral methods to be 2-oxo-5-pentyl-3-cyclopentene-1-octanoic acid (trivial name, 10-oxo-11-phytoenoic acid). Steric analysis demonstrated that the relative configuration of the two side chains attached to the five-membered ring was cis, and that the compound was a racemate comprising equal parts of the 9(R), 13(R) and 9(S), 13(S) enantiomers. Experiments in which specific trapping products of the two intermediates 9(S)-hydroperoxy-10(E), 12(Z)-octadecadienoic acid and 9(S), 10-epoxy-10, 12(Z)-octadecadienoic acid were isolated and characterized demonstrated the presence of 9-lipoxygenase and allene oxide synthase activities in the tissue preparation used. The allene oxide generated from linoleic acid by action of these enzymes was further converted into the cyclopentenone and α-ketol products by cyclization and hydrolysis, respectively. Incubation of [1-¹⁴C]linolenic acid with the preparation of potato stolons afforded 2-oxo-5-[2′(Z)-pentenyl]-3-cyclopentene-1-octanoic acid (trivial name, 10-oxo-11, 15(Z)-phytodienoic acid), i.e., an isomer of the jasmonate precursor 12-oxo-10, 15(Z)-phytodienoic acid. Quantitative determination of 10-oxo-11-phytoenoic acid in linoleic acid-supplied homogenates of different parts of the potato plant showed high levels in roots and stolons, lower levels in developing tubers, and no detectable levels in leaves.     

Efficient and Specific Conversion of 9-Lipoxygenase Hydroperoxides in the Beetroot. Formation of Pinellic Acid

The linoleate 9-lipoxygenase product 9(S)-hydroperoxy-10(E),12(Z)-octadecadienoic acid was stirred with a crude enzyme preparation from the beetroot (Beta vulgaris ssp. vulgaris var. vulgaris) to afford a product consisting of 95% of 9(S),12(S),13(S)-trihydroxy-10(E)-octadecenoic acid (pinellic acid). The linolenic acid-derived hydroperoxide 9(S)-hydroperoxy-10(E),12(Z),15(Z)-octadecatrienoic acid was converted in an analogous way into 9(S),12(S),13(S)-trihydroxy-10(E),15(Z)-octadecadienoic acid (fulgidic acid). On the other hand, the 13-lipoxygenase-generated hydroperoxides of linoleic or linolenic acids failed to produce significant amounts of trihydroxy acids. Short-time incubation of 9(S)-hydroperoxy-10(E),12(Z)-octadecadienoic acid afforded the epoxy alcohol 12(R),13(S)-epoxy-9(S)-hydroxy-10(E)-octadecenoic acid as the main product indicating the sequence 9-hydroperoxide → epoxy alcohol → trihydroxy acid catalyzed by epoxy alcohol synthase and epoxide hydrolase activities, respectively. The high capacity of the enzyme system detected in beetroot combined with a simple isolation protocol made possible by the low amounts of endogenous lipids in the enzyme preparation offered an easy access to pinellic and fulgidic acids for use in biological and medical studies.     

Linoleic acid metabolism in the red algaLithothamnion corallioides: Biosynthesis of 11(R)-hydroxy-9(Z),12(Z)-octadecadienoic acid

Incubation of [1-¹⁴C]linoleic acid with an enzyme preparation obtained from the red algaLithothamnion corallioides Crouan resulted in the formation of 11-hydroxy-9(Z),12(Z)-octadecadienoic acid as well as smaller amounts of 9-hydroxy-10(E),12(Z)-octadecadienoic acid, 13-hydroxy-9(Z),11(E)-octadecadienoic acid and 11-keto-9(Z),12(Z)-octadecadienoic acid. Steric analysis showed that the 11-hydroxyoctadecadienoic acid had the (R) configuration. The 9- and 13-hydroxyoctadecadienoic acids were not optically pure, but were due to mixtures of 75% (R) and 25% (S) enantiomers (9-hydroxyoctadecadienoate), and 24% (R) and 76% (S) enantiomers (13-hydroxy-octadecadienoate). 11-Hydroxyoctadecadienoic acid was unstable at acidic pH. In acidified water, equal parts of 9(R,S)-hydroxy-10(E),12(Z)-octadecadienoate and 13(R,S)-hydroxy-9(Z),11(E)-octadecadienoate, plus smaller amounts of the corresponding (E),(E) isomers were produced. In aprotic solvents, acid treatment resulted in dehydration and in the formation of equal amounts of 8,10,12- and 9,11,13-octadecatrienoates. The enzymatic conversion of linoleic acid into the hydroxyoctadecadienoic acids and the ketooctadecadienoic acid was oxygen-dependent; however, inhibitor experiments indicated that neither lipoxygenase nor cytochrome P-450 were involved in the conversion. This conclusion was supported by experiments with¹⁸O₂ and H₂ ¹⁸O, which demonstrated that the hydroxyl oxygen of the hydroxy-octadecadienoic acids and the keto oxygen of the 11-ketooctadecadienoic acid were derived from water and not from molecular oxygen. The term “oxylipin” was introduced recently (ref. 1) as an encompassing term for oxygenated compounds which are formed from fatty acids by reaction(s) involving at least one step of mono- or dixoygenase-catalyzed oxygenation.     

Biotransformation of linoleic acid by Clavibacter sp. ALA2: Heterocyclic and heterobicyclic fatty acids

Clavibacter sp. ALA2 transformed linoleic acid into a variety of oxylipins. In previous work, three novel fatty acids were identified, (9Z)-12,13,17-trihydroxy-9-octadecenoic acid and two tetrahydrofuran-(di)hydroxy fatty acids. In this report, we confirm the structures of the tetrahydrofuran-(di)hydroxy fatty acids by nuclear magnetic resonance as (9Z)-12-hydroxy-13,16-epoxy-9-octadecenoic acid and (9Z)-7,12-dihydroxy-13,16-epoxy-9-octadecenoic acid. Three other products of the biotransformation were identified as novel heterobicyclic fatty acids, (9Z)-12,17;13,17-diepoxy-9-octadecenoic acid, (9Z)-7-hydroxy-12,17;13,17-diepoxy-9-octadecenoic acid, and (9Z)-12,17;13,17-diepoxy-16-hydroxy-9-octadecenoic acid. Thus, Clavibacter ALA2 effectively oxidized linoleic acid at C-7,-12,-13,-16, and/or-17.     

Fatty acid hydroperoxide isomerase inSaprolegnia parasitica: Structural studies of epoxy alcohols formed from isomeric hydroperoxyoctadecadienoates

The major part (80%) of the fatty acid hydroperoxide isomerase activity present in homogenates of the fungus,Saprolegnia parasitica, was localized in the particle fraction sedimenting at 105,000×g. 13(S)-Hydroperoxy-9(Z),11(E)-octadecadienoic acid and 9(S)-hydroperoxy-10(E),12(Z)-octadecadienoic acid were both good substrates for the particle-bound hydroperoxide isomerase. The products formed from the 13(S)-hydroperoxide were identified as an α,β- and a γ,δ-epoxy alcohol, i.e., 11(R),12(R)-epoxy-13(S)-hydroxy-9(Z)-octadecenoic acid and 9(S),10(R)-epoxy-13(S)-hydroxy-11(E)-octadecenoic acid, respectively. The 9(S)-hydroperoxide was converted in an analogous way into an α,β-epoxy alcohol, 10(R),11(R)-epoxy-9(S)-hydroxy-12(Z)-octadecenoic acid and a γ,δ-epoxy alcohol, 12(R),13(S)-epoxy-9(S)-hydroxy-10(E)-octadecenoic acid. 9(R,S)-Hydroperoxy-10(E),12(E)-octadecadienoic acid and 13(R,S)-hydroperoxy-9(E),11(E)-octadecadienoic acid were poor substrates for theS. parasitica hydroperoxide isomerase. Experiments with 13(R,S)-hydroperoxy-9(Z),11(E)-octadecadienoic acid showed that the 13(R)-hydroperoxy enantiomer was slowly isomerized by the enzyme. The major product was identified as α,β-epoxy alcohol 11(R),12(R)-epoxy-13(R)-hydroxy-9(Z)-octadecenoic acid.     

Influence of moderate amounts of trans fatty acids on the formation of polyunsaturated fatty acids

The effect of trans fatty acids from partially hydrogenated soybean oil and butterfat on the formation of polyunsaturated fatty acids was investigated. Five groups of rats were fed diets that contained 20 wt% fat. The content of linoleic acid was adjusted to 10 wt% of the dietary fats in all diets, whereas the amount of trans fatty acids from partially hydrogenated soybean oil (PHSBO) was varied from 4.5 to 15 wt% in three of the five diets. The fourth group received trans fatty acids from butterfat (BF), while the control group was fed palm oil without trans fatty acids. Trans fatty acids in the diet were portionally reflected in rat liver and heart phosphatidylethanolamine (PE), phosphatidylcholine (PC), phosphatidylinositol, and phosphatidylserine. Incorporation in the sn-1 position was compensated by a decrease in saturated fatty acids. Trans fatty acids were not detected in diphosphatidylglycerol. Compared to the presence in the dietary fats, 8t- and 10t-18:1 were discriminated against in the incorporation in PE and PC from liver and heart, whereas 9t- and 12t-18:1 were preferred. The formation of 20:4n-6 was not influenced by 4.5 wt% trans fatty acids (from PHSBO) but apparently was by 10 wt% in liver. In contrast, even a content of 2.5 wt% trans fatty acids from BF reduced the formation of 20:4n-6. The inhibitory effect of trans isomers on linoleic acid conversion was reflected less in heart than in liver and less for PE than for PC. Groups with trans fatty acids showed increased 22:6n-3 and 22:5n-3 deposition in liver and heart PE and PC.     

A Facile and Efficient Method for the Synthesis of Labeled and Unlabeled Very Long Chain Polyunsaturated Fatty Acids

Several methods are available for elongation of fatty acid acyl chains. The present paper describes adaptation to the fatty acid field of a previously published protocol for manganese-based Wurtz type coupling of alkyl bromides. 22-Bromo-3(Z),6(Z),9(Z),12(Z),15(Z),18(Z)-docosahexaene, easily prepared from 4(Z),7(Z),10(Z),13(Z),16(Z),19(Z)-docosahexaenoic acid, was coupled to homologous ω-bromoesters by stirring for 4 hours at 40°C in the presence of manganese powder, a nickel catalyst and terpyridine. This afforded in yields of 70–75% a series of ω3-hexaenoates of chain lengths of 32–40 carbons. The corresponding fatty acids of >98% purity were obtained following saponification and final purification. By using methyl [2,2,3,3,4,4-²H₆]10-bromodecanoate as coupling partner it was possible to prepare a very long chain fatty acid in isotopically labeled form, i.e., [2,2,3,3,4,4-²H₆]14(Z),17(Z),20(Z),23(Z),26(Z),29(Z)-dotriacontahexaenoic acid. Also prepared were the monounsaturated long chain fatty acids 15(Z)-octadecenoic acid and 15(Z)-tetracosenoic acid. Very long chain fatty acids have been isolated from retina and other tissues and are of biological relevance. The methodology described will assist in further analytical and biological studies in this field.     

Metabolic profile of linoleic acid in stored apples: Formation of 13(R)-hydroxy-9(Z),11(E)-octadecadienoic acid

During our ongoing project on the biosynthesis of R-(+)-octane-1,3-diol the metabolism of linoleic acid was investigated in stored apples after injection of [1-¹⁴C]-, [9,10,12,13-³H]-, ¹³C₁₈- and unlabeled substrates. After different incubation periods the products were analyzed by gas chromatography-mass spectroscopy (MS), high-performance liquid chromatography-MS/MS, and HPLC-radiodetection. Water-soluble compounds and CO₂ were the major products whereas 13(R)-hydroxy- and 13-keto-9(Z),11(E)-octadecadienoic acid, 9(S)-hydroxy-and 9-keto-10(E),12(Z)-octadecadienoic acid, and the stereoisomers of the 9,10,13- and 9,12,13-trihydroxyoctadecenoic acids were identified as the major metabolites found in the diethyl ether extracts. Hydroperoxides were not detected. The ratio of 9/13-hydroxy- and 9/13-keto-octadecadienoic acid was 1∶4 and 1∶10, respectively. Chiral phase HPLC of the methyl ester derivatives showed enantiomeric excesses of 75% (R) and 65% (S) for 13-hydroxy-9(Z),11(E)-octadecadienoic acid and 9-hydroxy-10(E),12(Z)-octadecadienoic acid, respectively. Enzymatically active homogenates from apples were able to convert unlabeled linoleic acid into the metabolites. Radiotracer experiments showed that the transformation products of linoleic acid were converted into (R)-octane-1,3-diol. 13(R)-Hydroxy-9(Z), 11(E)-octadecadienoic acid is probably formed in stored apples from 13-hydroperoxy-9(Z),11(E)-octadecadienoic acid. It is possible that the S-enantiomer of the hydroperoxide is primarily degraded by enzymatic side reactions, resulting in an enrichment of the R-enantiomer and thus leading to the formation of 13(R)-hydroxy-9(Z),11(E)-octadecadienoic acid.     

Why not be a queen? Regioselectivity in mandibular secretions of honeybee castes

Both female castes of the honeybee (Apis mellifera L.) synthesize hydroxylated 2(E)-decenoic acids in their mandibular glands. Queens produce 9-hydroxy-2(E)-decenoic acid as part of their primer pheromone, while workers produce the regioisomeric 10-hydroxy acid, probably as a larval food source and an antiseptic secretion. Both workers and queens are biosynthetically competent to produce the other caste's dominant hydroxylated compound, as both isomers can be detected in queens and workers. We investigated the source of the caste-determined regioselectivity of hydroxy acid biosynthesis by investigating the production and interconversion of these compounds in isolated worker honeybee mandibular glands with specifically deuterated precursors. Gas chromatographic-mass spectroscopic identification of the labeled product indicates that octadecanoic acid is converted into 10-hydroxy-2(E)-decenoic acid with higher efficiency than either hexadecanoic or decanoic acids. 10-Hydroxydecanoic acid is readily converted into 10-hydroxy-2(E)-decenoic acid as expected in the -oxidation process. The saturated and unsaturated 10-hydroxy acids are oxidized to the corresponding ten carbon diacids.     

Rational Engineering of Hydratase from Lactobacillus acidophilus Reveals Critical Residues Directing Substrate Specificity and Regioselectivity

Enzymatic conversion of fatty acids (FAs) by fatty acid hydratases (FAHs) presents a green and efficient route for high-value hydroxy fatty acid (HFA) production. However, limited diversity was achieved among HFAs, to date, with respect to chain length and hydroxy position. In this study, two highly similar FAHs from Lactobacillus acidophilus were compared: FA-HY2 has a narrow substrate scope and strict regioselectivity, whereas FA-HY1 utilizes longer chain substrates and hydrates various double-bond positions. It is revealed that three active-site residues play a remarkable role in directing substrate specificity and regioselectivity of hydration. If these residues on FA-HY2 are mutated to the corresponding ones in FA-HY1, a significant expansion of substrate scope and a distinct enhancement in hydration of double bonds towards the ω-end of FAs is observed. A three-residue mutant of FA-HY2 (TM-FA-HY2) displayed an impressive reversal of regioselectivity towards linoleic acid, shifting the ratio of the HFA regioisomers (10-OH/13-OH) from 99:1 to 12:88. Notable changes in regioselectivity were also observed for arachidonic acid and for C₁₈ polyunsaturated fatty acid substrates. In addition, TM-FA-HY2 converted eicosapentaenoic acid into its 12-hydroxy product with high conversion at the preparative scale. Furthermore, it is demonstrated that microalgae are a source of diverse FAs for HFA production. This study paves the way for tailor-made FAH design to enable the production of diverse HFAs for various applications from the polymer industry to medical fields.     

Hydroxy fatty acids through hydroxylation of oleic acid with selenium dioxide/tert.-butylhydroperoxide

Oleic acid was hydroxylated in the allylic positions with the selenium dioxide/tert.-butylhydroperoxide system to give 8-hydroxy-9(E)-octadecenoic acid, 11-hydroxy-9(E)-octadecenoic acid and the novel 8,11-dihydroxy-9(E)-octadecenoic acid. This is a viable method for obtaining hydroxy fatty acids. The unsaturated hydroxy acids were hydrogenated with the hydrazine/air system to give the cor-responding saturated products. 8,11-Dihydroxyoctadecanoic acid thus obtained is also a novel compound. The saturated and unsaturated dihydroxy products were obtained aserythro/threo isomers as determined by nuclear magnetic resonance. Presented in part at the 83rd AOCS Annual Meeting, Toronto, Ontario, Canada, 1992.     

Fatty acid composition of French infant formulas with emphasis on the content and detailed profile oftrans fatty acids

The aim of the present study was to identify and quantitatetrans isomers of C18 fatty acids in some French infant formulas. Twenty powdered infant formulas were purchased in pharmacies and supermarkets in order to assess theirtrans mono- and poly-unsaturated fatty acids content. The fatty acid profiles were examined using methyl and isopropyl ester derivatives. The combination of gas-liquid chromatography, high-performance liquid chromatography, and silver nitrate thin-layer chromatography was needed to describe the detailed fatty acid compositions of the samples, includingtrans isomers of unsaturated C18 fatty acids. All the samples containedtrans isomers of C18∶1 acid (mean level 1.97±0.28% of total fatty acids), with vaccenic acid being generally the major isomer (15 out of 20 samples), thus indicating the origin from bovine milk. All the formulas also contained various isomers of linoleic and α-linolenic acids, but at lower levels.Trans PUFA isomers are the same as those present in deodorized oils. In conclusion, all the infant formulas analyzed in this study contained sometrans fatty acids, including isomers of essential fatty acids. This should be taken into account in the dietary intake of the newborn.     

Production of odd chain polyunsaturated fatty acids byMortierella fungi

A soil isolate,Mortierella alpina 1S-4, was found to show high production of odd chain polyunsaturated fatty acids (PUFAs) among various arachidonic acid-producingMortierella strains tested. The fungus mainly accumulated 5,8,11,M-cis-nonadecatetraenoic acid. With 5%n-hepta-decane and 1% yeast extract as growth substrates, the amount of C_19:4:4 acid accumulated reached 44.4 mg/g dry mycelia (0.68 mg/mL of culture broth). This value accounted for 11.2% of the total fatty acids in the extracted lipids from mycelia, and odd chain fatty acids comprised over 95% of the total mycelial fatty acids. The addition of sesamin, a specific inhibitor of A5 desaturation, caused an increase in C_19:3 acid and an accompanying decrease in C_19:4 acid. On the other hand, species ofMortierella that could not produce C-20 PUFAs accumulated C-17 acids, but no C-19 PUFAs, when grown with fatty substrates with an odd chain skeleton. The odd chain PUFAs were distributed in both neutral and polar lipids. The biosynthetic route to C_19:4 acid was presumed to mimic the n-6 route to arachidonic acid as follows: C_17:0 → C_17:1→ C_17:2→ C_17:3 → C_19:3 → C_19:4 acids. On leave from Suntory Ltd.