Monday, August 11, 2008 - 3:00 PM
S35
Unique fatty acid transformation catalyzed by anaerobic bacteria and its application for conjugated fatty acid production
Jun Ogawa1, Shigenobu Kishino2, Kenzo Yokozeki2, and Sakayu Shimizu1. (1) Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kitashirakawa-oiwakecho, Sakyo-ku, Kyoto, 606-8502, Japan, (2) Laboratory of Industrial Microbiology, Graduate School of Agriculture, Kyoto University, Kitashirakawa-oiwakecho, Sakyo-ku, Kyoto, 606-8502, Japan
To understand fatty acid transformation in anaerobic bacteria is important to improve fatty acid profile of diary products and to develop novel microbial methods for functional lipid production especially conjugated fatty acids. We investigated polyunsaturated fatty acid transformation in anaerobic bacteria and found unique reactions as summarized below.
Isomerization: Lactic acid bacteria isomerized linoleic acid (cis-9,cis-12-18:2) to conjugated linoleic acid (CLA). The produced CLA consisted of cis-9,trans-11-octadecadienoic acid (CLA1) and trans-9,trans-11-octadecadienoic acid (CLA2). Similar reactions were observed with C18 fatty acids with cis-9,cis-12 non-conjugated diene system. The enzyme system was found to be consisted of three proteins and required cofactors of oxido-reduction reactions.
Dehydration: Lactic acid bacteria transformed ricinoleic acid (12-hydroxy-cis-9-octadecenoic acid) to CLA (a mixture of CLA1 and CLA2). Castor oil, a triacylglycerol rich in ricinoleic acid, was also found as a substrate for CLA production by lactic acid bacteria with the help of lipase-catalyzing triacylglycerol hydrolysis.
Hydration: Hydrating reaction of double bonds in fatty acid was screened in lactic acid bacteria, and found that Pediococcus sp. produced a variety of hydroxyl fatty acids including a dihydroxyl fatty acid (10-hydroxy, 13-hydroxy, and 10,13-dihydroxy fatty acids) from C18 fatty acids with cis-9,cis-12 non-conjugated diene system.
Saturation: Clostridium bifermentans saturated C20 polyunsaturated fatty acids of arachidonic acid (cis-5,cis-8,cis-11,cis-14-20:4) and EPA (cis-5,cis-8,cis-11,cis-14,cis-17-20:5) into cis-5,cis-8,trans-13-20:3 and cis-5,cis-8,trans-13,cis-17-20:4, respectively. Similar reactions were observed with C18 and C20 fatty acids with omega-6,omega-9 non-conjugated cis,cis-diene system. A conjugated isomer of EPA, cis-5,cis-8,cis-11,trans-13,cis-17-20:4 and cis-5,cis-8,trans-11,trans-13,cis-17-20:4 was identified as an intermediate of EPA saturation by C. bifermentans.
Isomerization: Lactic acid bacteria isomerized linoleic acid (cis-9,cis-12-18:2) to conjugated linoleic acid (CLA). The produced CLA consisted of cis-9,trans-11-octadecadienoic acid (CLA1) and trans-9,trans-11-octadecadienoic acid (CLA2). Similar reactions were observed with C18 fatty acids with cis-9,cis-12 non-conjugated diene system. The enzyme system was found to be consisted of three proteins and required cofactors of oxido-reduction reactions.
Dehydration: Lactic acid bacteria transformed ricinoleic acid (12-hydroxy-cis-9-octadecenoic acid) to CLA (a mixture of CLA1 and CLA2). Castor oil, a triacylglycerol rich in ricinoleic acid, was also found as a substrate for CLA production by lactic acid bacteria with the help of lipase-catalyzing triacylglycerol hydrolysis.
Hydration: Hydrating reaction of double bonds in fatty acid was screened in lactic acid bacteria, and found that Pediococcus sp. produced a variety of hydroxyl fatty acids including a dihydroxyl fatty acid (10-hydroxy, 13-hydroxy, and 10,13-dihydroxy fatty acids) from C18 fatty acids with cis-9,cis-12 non-conjugated diene system.
Saturation: Clostridium bifermentans saturated C20 polyunsaturated fatty acids of arachidonic acid (cis-5,cis-8,cis-11,cis-14-20:4) and EPA (cis-5,cis-8,cis-11,cis-14,cis-17-20:5) into cis-5,cis-8,trans-13-20:3 and cis-5,cis-8,trans-13,cis-17-20:4, respectively. Similar reactions were observed with C18 and C20 fatty acids with omega-6,omega-9 non-conjugated cis,cis-diene system. A conjugated isomer of EPA, cis-5,cis-8,cis-11,trans-13,cis-17-20:4 and cis-5,cis-8,trans-11,trans-13,cis-17-20:4 was identified as an intermediate of EPA saturation by C. bifermentans.