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Biohydrogenation of linoleic acid by rumen fungi compared with rumen bacteria
Article first published online: 10 APR 2007
DOI: 10.1111/j.1365-2672.2007.03317.x
Additional Information
How to Cite
Nam, I. and Garnsworthy, P. (2007), Biohydrogenation of linoleic acid by rumen fungi compared with rumen bacteria. Journal of Applied Microbiology, 103: 551–556. doi: 10.1111/j.1365-2672.2007.03317.x
Publication History
- Issue published online: 10 APR 2007
- Article first published online: 10 APR 2007
- 2006/0919: received 28 June 2006, revised 7 November 2006 and accepted 12 November 2006
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Keywords:
- biohydrogenation;
- conjugated linoleic acid;
- rumen bacteria;
- rumen fungi
Abstract
Aims: To investigate biohydrogenation of linoleic acid by rumen fungi compared with rumen bacteria, and to identify the fungus with the fastest biohydrogenation rate.
Methods and Results: Biohydrogenation of linoleic acid by mixed rumen fungi and mixed rumen bacteria were compared in vitro. With mixed rumen bacteria, all biohydrogenation reactions were finished within 100 min of incubation and the end product of biohydrogenation was stearic acid. With mixed rumen fungi, biohydrogenation proceeded more slowly over a 24-h period. Conjugated linoleic acid (CLA; cis-9, trans-11 C18 : 2) was an intermediate product, and vaccenic acid (VA; trans-11 C18 : 1) was the end product of biohydrogenation. Fourteen pure fungal isolates were tested for biohydrogenation rate. DNA sequencing showed that the isolate with the fastest rate belonged to the Orpinomyces genus.
Conclusions: It is concluded that rumen fungi have the ability to biohydrogenate linoleic acid, but biohydrogenation is slower in rumen fungi than in rumen bacteria. The end product of fungal biohydrogenation is VA, as for group A rumen bacteria. Orpinomyces is the most active biohydrogenating fungus.
Significance and Impact of the Study: This is the first study to demonstrate that rumen fungi can biohydrogenate fatty acids. Fungi could influence CLA content of ruminant products.