Clostridium proteoclasticum: a ruminal bacterium that forms stearic acid from linoleic acid

R. John Wallace, Lal C. Chaudhary, Nest McKain, Neil R. McEwan, Anthony J. Richardson, Philip E. Vercoe, Nicola D. Walker, Delphine Paillard

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109 Citations (Scopus)


The aim of this study was to identify ruminal bacteria that form stearic acid (18 : 0) from linoleic acid (cis-9,cis-12-18 : 2). One 18 : 0-producing isolate, P-18, isolated from the sheep rumen was similar in morphology and metabolic properties to 'Fusocillus' spp. isolated many years ago. Phylogenetic analysis based on nearly full-length 16S rRNA gene sequence (> 1300 bp) analysis indicated that the stearate producer was most closely related to Clostridium proteoclasticum B316(T). Clostridium proteoclasticum B316(T) was also found to form 18 : 0, as were other bacteria isolated elsewhere, which occurred in the same family subclass of the low G+C% Gram-positive bacteria, related to Butyrivibrio fibrisolvens. These bacteria are not clostridia, and the ability to form 18 : 0 was present in all strains in contrast to proteolytic activity, which was variable. Production of 18 : 0 occurred in growing, but not in stationary-phase, bacteria, which made detection of biohydrogenating activity difficult, because of the inhibitory effects of linoleic acid on growth.

Original languageEnglish
Pages (from-to)195-201
Number of pages7
JournalFEMS Microbiology Letters
Issue number2
Publication statusPublished - Dec 2006


  • biohydrogenation
  • Butyrivibrio
  • Clostridium proteoclasticum
  • Fusocillus
  • stearate
  • unsaturated fatty acids
  • Butyrivibrio fibrisolvens
  • bovine rumen
  • SP-NOV.
  • chromatography
  • hydrogenation
  • Hungatei


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