Oleic 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... 

Based on the postulated common metabolic pathway involved in DOD and TOD formation by PR3, it was assumed that palmitoleic acid containing a singular C9 cis double bond (a common structural property shared by oleic and ricinoleic acids), could be utilized by PR3 to produce hydroxy fatty acid. Bae et al. (2007) reported that palmitoleic acid could be utilized as a substrate for the production of hydroxy fatty acid by PR3. Structural analysis of the major product produced from palmitoleic acid by PR3 confirmed that strain PR3 could introduce two hydroxyl groups on carbon 7 and 9 with shifted migration of 9-cis double bond into 8-tram configuration, resulting in the formation of 7,10-dihydroxy-8( )-hexadecenoic acid (DHD) (Fig. 31.3).The time course study of DHD production showed that DHD formation was time-dependently increased, and peaked at 72 h after the addition of palmitoleic acid as substrate. However, production yield of DHD (23%) from palmitoleic acid was relatively low when compared to that of DOD (70%) from oleic acid (Hou and Bagby, 1991). 

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 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. 

We have been investigating the production of value-added products from soybean oil. A Japanese patent application by Soda et al. (2) claimed the production of ricinoleic acid from oleic acid by Bacillus pumilus. Our initial goal was to produce ricinoleic acid from oleic acid by biocatalysis and hence to reduce the dependency on imported castor oil. Although we could not demonstrate the production of ricinoleic acid from oleic acid as did other investigators, including Soda s own group (2), our efforts led to discoveries of many new hydroxy fatty acids. These new products have potential industrial applications. Microbial oxidation of unsaturated fatty acids was reviewed recently (3). 

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]. 

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. 

Mid-chain hydroxylations of unsaturated fatty acids are known so that hydration across a double bond (Figure 9.7(b)) yields the corresponding hydroxy fatty acid. In this way, 12-hydroxystearate has been produced from oleic acid and 15-hydroxylinoleic acid from linolenic acid in various species of Candida (see Ratledge, 1989b, 1993). Other biotransformation reactions, involving oxidations either mid-chain or at the 2-position of fatty acids, occur in various bacteria and moulds. As these are not detailed elsewhere in this chapter, and are peripheral to the main themes being covered, readers should refer to the more relevant review for further details (Ratledge, 1993). 

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