Ricinoleic acid hydroxy fatty acids produced

Traditional fermentation using microbial activity is commonly used for the production of nonvolatile flavor compounds such as acidulants, amino acids, and nucleotides. The formation of volatile flavor compounds via microbial fermentation on an industrial scale is still in its infancy. Although more than 100 aroma compounds may be generated microbially, only a few of them are produced on an industrial scale. The reason is probably due to the transformation efficiency, cost of the processes used, and our ignorance to their biosynthetic pathways. Nevertheless, the exploitation of microbial production of food flavors has proved to be successful in some cases. For example, the production of y-decalactone by microbial biosynthetic pathways lead to a price decrease from 20,000/kg to l,200/kg U.S. Generally, the production of lactone could be performed from a precursor of hydroxy fatty acids, followed by p-oxidation from yeast bioconversion (Benedetti et al., 2001). Most of the hydroxy fatty acids are found in very small amounts in natural sources, and the only inexpensive natural precursor is ricinoleic acid, the major fatty acid of castor oil. Due to the few natural sources of these fatty acid precursors, the most common processes have been developed from fatty acids by microbial biotransformation (Hou, 1995). Another way to obtain hydroxy fatty acid is from the action of LOX. However, there has been only limited research on using LOX to produce lactone (Gill and Valivety, 1997). 

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). 

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). 

Castor (Ricinus communis) is a model industrial crop. The seed is up to 60% oil, which is composed of 90% ricinoleic acid (12-hydroxy oleate), a fatty acid that produces literally hundreds of products, which include lithium grease, low VOC... 

Ricinoleic acid (12-D-hydroxyoctadec-c/j-9-enoic acid) is the major fatty acid in castor bean seeds and is readily metabolized in germination. Partial breakdown by the normal /3-oxidation pathway would produce 6-hydroxy-... 

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. 

Ricinoleic acid (D-12-hydroxyoctadec-cis-9-enoic acid), is an hydroxylated fatty acid which constitutes 85-90% of the seed fatty acids in castor bean plants (Ricinus communis L). This unusual fatty acid is also one of a series of related Hydroxy Fatty Acids (HFAs) produced in the seeds of Lesquerella species. In these species, which, like A. thaliana and rapeseed belong to the Brassicacae family, ricinoleic acid is generally a minor constituent. Major HFAs include densipolic (12-OH, 18 2 (3,9)), lesquerolic (14-OH, 20 1 (9)) and auricolic (14-OH, 20 2 (3,9)) acids. 

In a survey of the literature, the present author could only identify some 64 species from all orders and families of moulds that had been recorded as producing over 25% lipid although there were many more that had between 20 and 25% lipid and thus may be potentially oleaginous (Ratledge, 1989b). A selection of some of these moulds, taken from the main divisions of the moulds, is given in Table 9.7. It should be pointed out that C12 and C14 fatty acids are known to be produced in some abundance by some species of Entomophthora, and that the hydroxy fatty acid, ricinoleic acid, 12-hydroxyoleic acid, is produced by... 

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