title: Clostridium proteoclasticum: A ruminal bacterium that forms stearic acid from linoleic acid.
abstract: 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.
authors.affiliation: Rowett Research Institute, Bucksburn, Aberdeen, UK. john.wallace@rowett.ac.uk
authors.forename: R
authors.initials: R
authors.lastname: John Wallace
authors.forename: Lal C
authors.initials: LC
authors.lastname: Chaudhary
authors.forename: Nest
authors.initials: N
authors.lastname: McKain
authors.forename: Neil R
authors.initials: NR
authors.lastname: McEwan
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Richardson
authors.forename: Philip E
authors.initials: PE
authors.lastname: Vercoe
authors.forename: Nicola D
authors.initials: ND
authors.lastname: Walker
authors.forename: Delphine
authors.initials: D
authors.lastname: Paillard
mesh_terms: D000818:Animals; D003013:Clostridium / Q000302:isolation & purification / Q000378:metabolism*; D006865:Hydrogenation; D019787:Linoleic Acid / Q000378:metabolism*; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000145:classification; D012756:Sheep / Q000382:microbiology; D013229:Stearic Acids / Q000378:metabolism*; D013279:Stomach, Ruminant / Q000382:microbiology*
chemical_list: D012336:RNA, Ribosomal, 16S; D013229:Stearic Acids; C031183:stearic acid; D019787:Linoleic Acid