Inhibition of growth of the green algaChlorella pyrenoidosa by unsaturated fatty acids

The activity of a number of unsaturated fatty acids in inhibiting the growth of the green algaChlorella pyrenoidosa has been studied using the paper disk-agar plate method. Acrylic and undecylenic acids were highly active, but other θ-unsaturated fatty acids tested were only weakly active. Oleic and elaidic acids were inactive at 0.2 M, but other C₁₈-C₂₂ acids with 2 to 6 double bonds were generally active down to a concentration of 0.01–0.005 M. Activity with chaulmoogric acid was noted down at 0.002–0.001 M. Diffusion rates of the acids through the agar seem to affect the size of the inhibition zones. The implications that polyunsaturated fatty acids may play a role in algal ecology are discussed.     

Inhibitory effects of terpene alcohols and aldehydes on growth of green algaChlorella pyrenoidosa

The growth of the green algaChlorella pyrenoidosa was inhibited by terpene alcohols and the terpene aldehyde citral. The strongest activity was shown by citral. Nerol, geraniol, and citronellol also showed pronounced activity. Strong inhibition was linked to acyclic terpenes containing a primary alcohol or aldehyde function. Inhibition appeared to be taking place through the vapor phase rather than by diffusion through the agar medium from the terpene-treated paper disks used in the system. Inhibition through agar diffusion was shown by certain aged samples of terpene hydrocarbons but not by recently purchased samples.     

Traditional analytical chemistry of fatty acids and their derivatives

Industrial fatty acids and their derivatives are generally manufactured under strict quality control and sold under rigid specifications. The purchase specifications are normally prescribed by a series of traditional “wet” analytical methods. These methods include acid value, saponification value, iodine value, hydroxyl value, water content, and others. Occasionally, other information is specified; this may include for tall oil fatty acids, rosin content, and free glycerol in monoglycerides, diene value for drying fatty acids, and conjugated fatty acids for specialized fatty acids. The most common fatty acid derivatives of the industrial fatty acids are anionic and nonionic surfactants and the nitrogen derivatives such as amines and quaternary ammonium salts. Rigid quality control is also applied to these compounds. The amine value and the determination of primary, secondary, and tertiary amines are the key analytical methods applied to amine derivatives. Quaternary ammonium compounds present unique problems; these are in a present state of methods improvement. Physical property test methods are often used to characterize fatty acids. Though simple in concept, they are often the most difficult to meet in purchase specifications. Examples of these tests are viscosity, titer, color, color stability, flash and fire point.     

Comparative fatty acids of the dolphin and the herring

The tissue samples from two bottlenosed dolphins (Tursiops truncatus) became available, and it was dedided to examine the fatty acid compositions of the phospholipid fracations. The food chain of the dolphin provides a vast preponderance of ω3 series fatty acids compared to ω6, while the land food chain provides a more even balance between the two series. The ancestors of the dolphin had evolved on the land with the terrestrial ω3:ω6 balance, but the dolphin now lives in an ω3-rich environment. The investigations were carried out to discover whether the dolphin reflected its marine environment or alternatively its evolutionary history. The results showed that the fatty acids of the dolphin bear a much closer resemblance to those of land mammals than to those of other marine vertebrates.     

Phenylethyl esters of fatty acids for the analytical resolution of petroselinate and oleate

2-Phenylethyl esters of fatty acids were prepared readily by esterification of free fatty acids or transesterification of other lipids. Compared with methyl esters, phenylethyl esters greatly improve the resolution of oleate and petroselinate by both gas and high-performance liquid chromatography, and the ultraviolet absorption of the phenylethyl esters facilitates detection of the derivatives by high-performance liquid chromatography (HPLC) ultraviolet detectors. The fatty acid compositions of corn and soybean oil obtained by analysis of phenylethyl esters agreed with those obtained with methyl esters. The phenylethyl esters were resolved and eluted on C-18 HPLC columns with much smaller solvent volumes than those reported for other aromatic esters.     

Biological studies with cyclopropenoids inactivated with fatty acids

Cyclopropenoids inactivated by reactingSterculia foetida oil with cottonseed oil fatty acids were fed at three dietary levels to growing rats and laying hens for 4 weeks. At the termination of the experiments, all animals were autopsied and examined microscopically for pathological lesions, but no pathology that could be related to dietary treatment was observed. Hemoglobin, packed cell volume and plasma cholesterol were similar in animals fed all of the diets. Growth rate of rats and egg production of hens fed the experimental diets were similar to those of animals fed the control diet. After 3 and 6 months of storage, eggs from hens fed the inactivated cyclopropenoids were normal and showed no evidence of the unusual characteristics of cyclopropenoid feeding. Lipids of heart, liver and adipose tissues of all the rats and hens varied little from the normal fatty acid composition. Small amounts of three unidentified fatty acids were found in the adipose tissues of rats fed the higher levels of inactivated cyclopropenoids. The results of these feeding studies suggest that inactivation of cyclopropenoids with fatty acids eliminates the unusual biological effects attributable to cyclopropenoids. Presented at the AOCS Meeting, New Orleans, April 1970.     

Comparison of various analytical techniques for the determination of essential fatty acids in hardened fats

In partially hydrogenated fats containing residual linoleic acid, linoleic acid isomers are found which have no essential fatty acid activity but contribute to the C-18 diene acid values; i.e., to the so-called linoleic acid values obtained by the usual physicochemical methods. Such hydrogenated fats and oil blends, particularly margarine oils, have now been analyzed by a biochemical procedure in the attempt to measure specifically the essential fatty acid content by a direct method. The latter procedure makes use of a lipoxidase enzyme specific for thecis, cis, methylene interrupted diene structure in polyunsaturated fatty acids having two or more double bonds. It is concluded that the biochemical method is equally as reliable as the combined use of the spectrophotometric and thiocyanometric procedures for estimating with precision the essential fatty acid content of hydrogenated fats containing residual dienes; the simplicity and speed of the biochemical method make it the procedure of choice.     

Further studies of the saturated methyl branched fatty acids ofVernix caseosa lipid

By the method of capillary gas chromatography-mass spectrometry, we have identified 35 monomethyl and 46 dimethyl branched acids in the saturated acids of vernix caseosa lipid with chain lengths ranging from C₁₁ to C₁₈. Many other mono-, di-, and trimethyl branched acids have been partially identified. All methyl branches were found to be on the even numbered C-atoms except for some terminal iso methyl groups. Three types of dimethyl branched acids were found: those with a terminal iso structure, those with a terminal anteiso structure, and those with neither iso nor anteiso structures. The 4-methyl branch predominated for all types of branched acids. Equivalent chain length data for di- and trimethyl branched acids were determined on a Pentasil (nonpolar) wall coated capillary column and checked by calculation from monomethyl branched acid data. Mass spectral identification was performed with and without the aid of a data system. A possible mode of formation of these acids is discussed.     

Kinetic studies on the esterification of free fatty acids in jatropha oil

Kinetic studies have been carried out on the esterification of free fatty acids (FFAs) in jatropha oil with methanol in the presence of sulphuric acid catalyst at 5 and 10 wt% concentrations relative to free fatty acids (0.4–0.8 wt% relative to oil) and methanol–FFA mole ratios ranging from 20:1 to 80:1. It has been found that a 60:1 methanol–FFA mole ratio and 5 wt% catalyst at 60°C and 500 rpm or above provided a final acid value lower than 1 mg KOH/g oil within 60 min. A kinetic model has been proposed with second‐order kinetics for both the forward and backward reactions. The effect of temperature on the reaction rate constants and equilibrium constant has been determined using Arrhenius and von't Hoff equations, respectively. The heat of reaction was found to be ?11.102 kJ/mol.     

Gas chromatography/tandem mass spectrometry as an analytical tool for the identification of fatty acids

Structures of fatty acids present at very low quantities in mycobacteria are difficult to determine. A commonly used strategy is to introduce heteroatoms into functional groups by chemical means before subjecting them to gas chromatography/tandem mass spectrometry (GC/MS/MS) analysis. Routinely used methods give very low abundance diagnostic ions leading to ambiguities in structural conclusions. GC/MS/MS associated with electron capture ionization of pentafluorobenzyl esters was used to study very complex mixtures of fatty acids fromMycobacterium fallax andM. aurum. The charge-remote fragmentation of fatty acid carboxylate anions was used for structure determination at the nanogram level of a large number of unsaturated, branched, and cyclopropane-containing fatty acids. Some of them have not been observed previously in these Mycobacteria. On the basis of these studies, biosynthetic pathways of unsaturated, branched, and cyclopropane-containing fatty acid are proposed.     

The separation of solid fatty acids from liquid fatty acids by the formation of acid soaps. II. Pilot plant studies

On contemplating pilot plant scale-up of the acid soap process for separating fatty acid mixtures into low and high iodine value fractions, improvements were desirable in acidifying agent used, and the method of separating the solid acid soaps. A further objective was to determine the range of applicability of the process. Studies indicated that CO₂ can be replaced by mineral acids, or by the fatty acids themselves. A continuous precoat vacuum filter is suitable for the separation of the solid acid soaps. The process is applicable to refinery foots as well as to distilled and undistilled fatty acids.     

Comparative rates of formation of fatty acids in the soybean seed during its development

Summary Lincoln soybeans harvested at successive stages of maturity showed continuous increases in amounts present of each of the fatty acids: saturated, oleic, linoleic, and linolenic. The iodine value and linolenic acid percentage of the oil decreased somewhat during the early stages of seed development. The linoleic acid and total oil percentage in the bean increased continuously until the 50th day then remained constant. Oleic and saturated acids fluctuated. No evidence for dehydrogenation of saturated fatty acids was obtained either in the oil analyses or in tests of soybean tissues for dehydrogenase activity. Journal Paper No. 717 of the Purdue Agricultural Experiment Station, Lafayette, Ind.     

Comparative studies on the fatty acid composition of moderately and extremely thermophilic bacteria

The fatty acids of three strains of extremely thermophilic bacteria and three strains of moderately thermophilic bacteria were examined by gas liquid chromatography. All the thermophiles contained straight, iso, and ante-iso branched fatty acids. Iso C_17∶0 acid was abundant in both the moderately thermophilic strains (10–33%) and the extremely thermophilic strains (50–61%). The pair of fatty acids iso C_15∶0 and iso C_17∶0 was the predominant pair in both the moderately (34–64%) and extremely (76–87%) thermophilic strains. The pair of fatty acids ante-iso C_15∶0 and ante-iso C_17∶0 was present in larger amount in moderately (25–34%) than in extremely (8.5–15%) thermophilic strains. No hydroxy cyclopropane, or unsaturated fatty acids were found. One extreme thermophile,Flavobacterium thermophilum HB-8 was grown at 6 different culture temperatures from 49–82 C, and the changes of its fatty acid composition were studied. The ratios of iso C_17∶0/iso C_15∶0 and ante-iso C_17∶0/ante-iso C_15∶0 were much greater at higher culture temperatures, indicating chain elongation.     

Phospholipid studies of marine organisms: New branched fatty acids fromStrongylophora durissima

The phospholipids of the spongeStrongylophora durissima were analyzed. The major phospholipids present were phosphatidylethanolamine (PE), phosphatidylcholine (PC), phosphatidylserine (PS), phosphatidylglycerol (PG) and phosphatidylinositol (PI). The major fatty acid components of the phospholipids consisted of short chain (C₁₄−C₁₉) and very long chain (C₂₅−C₃₀) “Demospongic” acids. Three novel branched Δ⁵ monounsaturated acids,Z-19-methyl-5-pentacosenoic,Z-19-methyl-5-hexacosenoic andZ-19-methyl-5-heptacosenoic acids were encountered in the sponge. The 3-saturated counterparts of these compounds, 19-methylpentacosanoic, 19-methylhexacosanoic and 19-methylheptacosanoic acids, as well as 19-methylpentacosanoic and 20-methyloctacosanoic acids also are hitherto undescribed acids present in the sponge. Trace amounts of 2 very long chain acids also were detected and their structures tentatively assigned as 19,21-dimethylheptacosanoic and 20,22-dimethyloctacosanoic acids. The distribution of these fatty acids according to phospholipid head groups also was described.     

Metabolism of odd-numbered fatty acids and even-numbered fatty acids in mouse

Fatty acids are converted into energy via beta-oxidation. Although almost all natural occurring fatty acids are even-numbered, there are some odd-numbered fatty acids too. The details of the metabolism rate of odd-numbered fatty acids, however, are not clear. In the present study, we simultaneously administered a triacylglycerol containing four types of labeled even-numbered (palmitic acid and stearic acid) and odd-numbered (pentadecanoic acid and heptadecanoic acid) fatty acids to mice to compare the rates of their metabolism. The rates of metabolism were evaluated based on the accumulation of the labeled fatty acids in the small intestine epithelium, liver, and epididymal fat. Odd-numbered fatty acids accumulated mainly in the epididymal fat. In contrast, there was no accumulation of even-numbered fatty acids observed in the small intestine epithelium, liver, or epididymal fat. These results suggest that odd-numbered fatty acids might not be favorable substrates for beta-oxidation-related enzymes.     

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.     

Production of fatty alcohols from fatty acids

Detergent-range alcohols from natural feedstock can be produced by high pressure hydrogenation of either methyl esters or fatty acids. The increasing quantities of fats and oils on the world market secure a reliable and economically priced material. Although fatty acid is an abundant worldwide commodity, most alcohol producers hydrogenate methyl esters, because direct hydrogenation of fatty acids is difficult as the catalyst is sensitive to acid attack. The process described here makes it possible to hydrogenate fatty acids directly to alcohols of high quality without prior esterification. The reaction takes place in the liquid phase over a fine-grained copper chromite slurry in a single reactor vessel. A special reactor design with an optimum arragement of the feeding nozzles causing an appropriate circulation of the reacting components inside the reactor facilitates the rapid “in situ” esterification reaction. This minimizes the free fatty acid concentration in the reactor to nearly zero. This results in a low consumption of catalyst. The most important advantages of the process are: direct feed of fatty acids of various origins, use of reasonably priced raw materials such as soapstock fatty acids and lower grade tallow acids, no process steps with methanol, and excellent economics. The process is industrially proven.