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ARS Home » Northeast Area » Ithaca, New York » Robert W. Holley Center for Agriculture & Health » Research » Publications at this Location » Publication #109636

Title: THE EFFECT OF LINOLEIC ACID CONCENTRATION ON THE CONJUGATED LINOLEIC ACID (CLA) PRODUCTION OF BUTYRIVIBRIO FIBRISOLVENS A38

Author
item KIM, YOUNG-JUN
item LIU, RUI
item BOND, DANIEL
item Russell, James

Submitted to: Applied and Environmental Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/22/2000
Publication Date: N/A
Citation: N/A

Interpretive Summary: Dairy products contain small amounts of conjugated linoleic acid (CLA), a fatty acid that combats obesity and cancer. CLA is produced by ruminal bacteria from linoleic acid (LA), but the this conversion was poorly understood. Our experiments indicated that growing cultures of B. fibrisolvens A38 did not produce significant amounts of CLA until the LA concentration was high, biohydrogenation was arrested, and the cell densit had declined. Based on these results it appears that the flow of CLA from the rumen may be due to LA-dependent bacterial death or lysis. Research on ruminal CLA production has the potential to increase the LA content of milk and improve human health.

Technical Abstract: Exponentially growing cultures of Butyrivibrio fibrisolvens A38 produced less conjugated linoleic acid (CLA) than stationary phase cells, and the glycolytic inhibitor, iodoacetate, increased the CLA production of cells incubated anaerobically. Stationary phase cells that were incubated aerobically produced more CLA than those incubated anaerobically, and CLA production and biohydrogenation were always inversely related. CLA was produced very rapidly, but washed cells pre-incubated with CLA did not produce additional CLA from linoleic acid (LA). CLA production was higher if more cells were present, and CLA accumulation was a linear function of the cell density. These results indicated that LA isomerase could not continually recycle to produce more CLA. Cultures that were gradually adapted to LA produced less CLA, and more of the LA was converted to trans-vaccenic acid (trans- C18:1). These results supported the idea that LA isomerase and reductase reactions of fatty acid biohydrogenation were obligately linked. Because growing cultures of B. fibrisolvens A38 did not produce significant amounts of CLA until the LA concentration was high, biohydrogenation was arrested, and the cell density had declined, the flow of CLA from the rumen may be due to LA-dependent bacterial death or lysis.