Thursday, August 2, 2007 - 10:05 AM
S164
Microbial and enzymatic processes for the production of functional lipids
Sakayu Shimizu, Jun Ogawa, and Eiji Sakuradani. Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kitashirakawa-oiwakecho, Sakyo-ku, Kyoto, 606-8502, Japan
The C20 polyunsaturated fatty acids (PUFAs) of n-6, n-3 and n-9 routes have versatile and unique biological activities. These PUFAs or lipids containing them are of highly potential in neutraceutical and pharmaceutical applications. We have reported that a fungus Mortierella alpina 1S-4 accumulates large amount of triacylgycerol rich in arachidonic acid (AA) on cultivation in a medium containing glucose as a major carbon source, and the resultant mycelia are a good source for this fatty acid. Various kinds of M. alpina mutants lacking desaturation activities involved in the AA biosynthesis pathway (n-6 route) were isolated. Some of these mutants operate new pathways of PUFA biosynthesis. For example, a mutant defective in delta-12 desaturation activity operates n-9 route, in place of n-6 one. The mutant does not produce any n-6 fatty acids commonly found in the parental strain, and alternatively accumulates three n-9 PUFAs (18:2, 20:2, and 20:3). Lactic acid bacteria produced conjugated linoleic acid (CLA) from linoleic acid. The produced CLA was identified as cis-9,trans-11-octadecadienoic acid and trans-9,trans-11-octadecadienoic acid. The washed cells of Lactobacillus plantarum AKU 1009a produced about 40 mg/ml CLA under the optimized conditions. Two successive reactions, hydration of linoleic acid to 10-hydroxy-12-octadecenoic acid (HY) and dehydrating isomerization of HY to CLA, were found to be involved in this transformation.