Linoleic acid hydroxy fatty acids produced

As mentioned in the introduction, 3-hydroxy fatty acids with functional groups can also be incorporated in poly(3HAMCL). Table 2 illustrates this with many examples of alkenes, 3-hydroxyalkenoic acids, and substituted 3-hy-droxyalkanoic acids that are readily integrated in poly(3HAMCL). Long chain fatty acids have also been used successfully as substrates for poly(3HAMCL) production. De Waard et al. [44] used oleic acid and linoleic acid to produce... 

It has been reported that a microbial isolate, Flavobacterium sp. strain DS5, produced 10-ketostearic acid (10-KSA) from oleic acid in 85% yield (Hou, 1994a). The purified product was white, plate-like crystals melting at 79.2°C. A small amount of 10-hydroxystearic acid (10-HSA) was also produced during the bioconversion, suggesting that oleic acid is converted to 10-KSA via 10-HSA, and the enzyme catalyzing the hydration is C-10 positional specific (Hou, 1994b, 1995). The DS5 bioconversion products from oleic, linoleic, a-linolenic, and y-linolenic acid are all 10-hydroxy fatty acids. The optimum time, pH, and temperature for the production of 10-KSA have been reported in flask... 

Since Wallen et al. (1962) reported the first bioconversion of oleic acid to 10-hydroxystearic acid by a Pseudomonad, microbial conversions of unsaturated fatty acids from different substrates by various microbial strains have been widely exploited to produce new, value-added products. Among the unsaturated fatty acids used for microbial production of hydroxy fatty acids, three (oleic, linoleic, and linolenic acids) were well studied as substrates to produce mono-, di-, and trihydroxy fatty acids. Recently, a bacterial strain Pseudomonas aeruginosa NRRL B-18602 (PR3) has been studied to produce hydroxy fatty acids from several fatty acid substrates. In this review, we introduce the production of hydroxy fatty acids from their corresponding fatty acid substrates by P. aeruginosa PR3 and their industrially valuable biological activities. 

Cholesterol is formed in the liver (85%) and intestine (12%) - this constitutes 97% of the body s cholesterol synthesis of 3.2 mmol/day (= 1.25 g/day). Serum cholesterol is esterized to an extent of 70-80% with fatty acids (ca. 53% linolic acid, ca 23% oleic acid, ca 12% palmitic acid). The cholesterol pool (distributed in the liver, plasma and erythrocytes) is 5.16 mmol/day (= 2.0 g/day). Homocysteine stimulates the production of cholesterol in the liver cells as well as its subsequent secretion. Cholesterol may be removed from the pool by being channelled into the bile or, as VLDL and HDL particles, into the plasma. The key enzyme in the synthesis of cholesterol is hydroxy-methyl-glutaryl-CoA reductase (HGM-CoA reductase), which has a half-life of only 3 hours. Cholesterol is produced via the intermediate stages of mevalonate, squalene and lanosterol. Cholesterol esters are formed in the plasma by the linking of a lecithin fatty acid to free cholesterol (by means of LCAT) with the simultaneous release of lysolecithin. (s. figs. 3.8, 3.9) (s. tab. 3.8)... 

Of interest is a unique alternative biosynthetic pathway for CLA. Ogawa et al. (2001) reported that a strain of Lactobacillus acidophilus, under micro-aerobic conditions, produced 1O-hydroxy-cA-12-octadcccnoic acid and 10-hydroxy-trans-12-octadecenoic acid as intermediates in the synthesis of cis-9, trans-11 and trans-9, cis-11 18 2. The conversion was induced by presence of linoleic acid, and a high yield of CLA was reported. Hudson et al. (1998, 2000) showed that lactic acid bacteria, including Lactobacillus, Pediococcus, and Streptococcus species, are the major unsaturated fatty acid hydrating bacteria in the rumen, converting oleic acid to 10-hydroxy stearic acid and linoleic acid to 10-hydroxy-12-octadecenoic acid and 13-hydroxy-9 octadecenoic acid. Thus, potentially, CLA may be produced also in the rumen from linoleic acid by pathways other than the classic isomerase described by Kepler et al. (1966). 

The biochemical reaction catalyzed by epoxygenase in plants combines the common oilseed fatty acids, linoleic or linolenic acids, with O2, forming only H2O and epoxy fatty acids as products (CO2 and H2O are utilized to make linoleic or linolenic acids). A considerable market currently exists for epoxy fatty acids, particularly for resins, epoxy coatings, and plasticizers. The U.S. plasticizer market is estimated to be about 2 billion pounds per year (Hammond 1992). Presently, most of this is derived from petroleum. In addition, there is industrial interest in use of epoxy fatty acids in durable paints, resins, adhesives, insecticides and insect repellants, crop oil concentrates, and the formulation of carriers for slow-release pesticides and herbicides (Perdue 1989, Ayorinde et al. 1993). Also, epoxy fatty acids can readily and economically be converted to hydroxy and dihydroxy fatty acids and their derivatives, which are useful starting materials for the production of plastics as well as for detergents, lubricants, and lubricant additives. Such renewable derived lubricant and lubricant additives should facilitate use of plant/biomass-derived fuels. Examples of plastics that can be produced from hydroxy fatty acids are polyurethanes and polyesters (Weber et al. 1994). As commercial oilseeds are developed that accumulate epoxy fatty acids in the seed oil, it is likely that other valuable products would be developed to use this as an industrial chemical feedstock in the future. 

Aspergillus nidulans uses a family of oxygenated long-chain fatty acids called psi factor (precocious sexual inducer), such as psiBa (8-hydroxy-18 2-9,12) and psiCa (5,8-dihydroxy-18 2-9,12) to modulate sexual and asexual spore development. Both hydroxyl fatty acids are produced by cytochrome P450-like fatty acid oxygenases using linoleic acid as a substrate (Tsitsigiannis et al. 2005). 

The production requires 2 fermentations. In the first fermentation, lipase enzymes liberate the unsaturated fatty acids of flaxseed oil. During the first feraientation, the hydrolyzed fatty acids, linolenic acid, linoleic acid and oleic acid, are converted to (respectively) 10-hydroxy-12(Z),15(Z)-octadecadienoic acid, 10-hydroxy-12(Z)-octadecenoic acid and 10-hydroxydecanoic acid by Pseudomonas sp. NRRL-2994. Pseudomonas sp. produced stereochemically pure d (R)-isomers of each of the hydroxy fatty acids (>95.8%) 23) at a concentration of >12 g/L in the fermentation broth. The resulting hydroxy fatty acids were recovered by phase separation technique, and used for the second fermentation. 

The strain DS5 system produced more keto product from palmitoleic and oleic acids and more hydroxy product from myristoleic, linoleic, and a- and y-linolenic acids. The reason for fliis preference is not clear. Among die 18-carbon unsaturated fatty acids, an additional double bond in either side of die C-10 position lowers the enzyme hydration activity. A hterature search revealed diat all microbial hydratases hydrate oleic and linoleic acids at the C-10 position (Fig. 2). Therefore, die positional specificity of microbial hydratases might be universal. 

In addition to 8-DOX products, G. graminis or its cell-free extracts can metabolize a variety of fatty acids into oxylipins. Of those substrates, the most interesting are linoleic and oleic acids, which are common in ascomycetes. Linoleic acid gives rise to 16-hydroxyoctadecadienoic acid and 17-hydroxyoctadecadienoic acid via cyt P-450 activity. 8,16-Dihydroxyoctadecadienoic acid and 8,17-hydroxy-octadecadienoic acid were also produced, apparently by a combination of 8-DOX and cyt P-450 activity [6,16]. 

The second edition includes important developments in the characterization by capillary gas chromatography-olfactometry of aroma and flavor impact of volatile decomposition products from polyunsaturated fatty acids and esters. Discussions are included on various mechanisms for the formation from linoleate of 4-hydroxy-2-nonenal, which has received much attention in the biochemical literature because of its cytotoxic properties, and its occurrence in oxidized LDL and in vegetable oils heated at frying temperatures. Some of the volatiles produced from fish oils are responsible for major problems in then-utilization, because they produce very powerful fishy odors and flavors perceptible at extremely low levels of oxidation. 

In most commercially important edible plant oils, the dominant fatty acids are oleic, linoleic and linolenic acids. Coconut oil is an exception in having the saturated 12 0 lauric acid as its major acid. Families of plants tend to produce characteristic oils that frequently contain unusual fatty acids. Examples are the erucic acid of rape-seed ricinoleic acid, the 18-carbon, monoenoic, hydroxy acid of the castor bean and vernolic acid, the 18-carbon, trienoic, epoxy acid of the Compositae. 

Important polyhydroxy acids are 9,10,12,13-tetrahydroxyocta-decanoic acids, known as sativic acids (several steric isomers exist), which are derived from linoleic acid. Oxidation of linolenic acid analogously produces 9,10,12,13,15,16-hexahydroxyoctadecanoic (linusic) acids. An overview of common hydroxy fatty acids is given in Table 3.6. 

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