title: Syntrophomonas zehnderi sp. nov., an anaerobe that degrades long-chain fatty acids in co-culture with Methanobacterium formicicum.
abstract: An anaerobic, mesophilic, syntrophic fatty-acid-oxidizing bacterium, designated strain OL-4(T), was isolated as a co-culture with Methanobacterium formicicum DSM 1535(NT) from an anaerobic expanded granular sludge bed reactor used to treat an oleate-based effluent. Strain OL-4(T) degraded oleate, a mono-unsaturated fatty acid, and straight-chain fatty acids C(4 : 0)-C(18 : 0) in syntrophic association with Methanobacterium formicicum DSM 1535(NT). Even-numbered fatty acids were degraded to acetate and methane whereas odd-numbered fatty acids were degraded to acetate, propionate and methane. Branched-chain fatty acids were not degraded. The bacterium could not grow axenically with any other substrate tested and therefore is considered to be obligately syntrophic. Fumarate, sulfate, thiosulfate, sulfur and nitrate could not serve as electron acceptors for strain OL-4(T) to degrade oleate or butyrate. Cells of strain OL-4(T) were curved rods, formed spores and showed a variable response to Gram staining. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain OL-4(T) was most closely related to the fatty-acid-oxidizing, syntrophic bacterium Syntrophomonas sp. TB-6 (95 % similarity), Syntrophomonas wolfei subsp. wolfei DSM 2245(T) (94 % similarity) and Syntrophomonas erecta DSM 16215(T) (93 % similarity). In addition to this moderate similarity, phenotypic and physiological characteristics, such as obligate syntrophy, spore formation and utilization of a broader substrate range, differentiated strain OL-4(T) from these Syntrophomonas species. Therefore strain OL-4(T) represents a novel species, for which the name Syntrophomonas zehnderi sp. nov. is proposed. The type strain is OL-4(T) (=DSM 17840(T)=JCM 13948(T)).
authors.affiliation: Laboratory of Microbiology, Wageningen University, Hesselink van Suchtelenweg 4, 6703 CT Wageningen, The Netherlands.|IBB-Institute for Biotechnology and Bioengineering, Centre for Biological Engineering, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal.
authors.forename: Diana Z
authors.initials: DZ
authors.lastname: Sousa
authors.affiliation: Laboratory of Microbiology, Wageningen University, Hesselink van Suchtelenweg 4, 6703 CT Wageningen, The Netherlands.
authors.forename: Hauke
authors.initials: H
authors.lastname: Smidt
authors.affiliation: IBB-Institute for Biotechnology and Bioengineering, Centre for Biological Engineering, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal.
authors.forename: M Madalena
authors.initials: MM
authors.lastname: Alves
authors.affiliation: Laboratory of Microbiology, Wageningen University, Hesselink van Suchtelenweg 4, 6703 CT Wageningen, The Netherlands.
authors.forename: Alfons J M
authors.initials: AJM
authors.lastname: Stams
mesh_terms: D000693:Anaerobiosis; D001421:Bacteria, Anaerobic / Q000145:classification* / Q000378:metabolism*; D019149:Bioreactors; D004269:DNA, Bacterial / Q000235:genetics; D004275:DNA, Ribosomal / Q000235:genetics; D005227:Fatty Acids / Q000378:metabolism*; D017014:Methanobacterium / Q000378:metabolism*; D008969:Molecular Sequence Data; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics
chemical_list: D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D005227:Fatty Acids; D012336:RNA, Ribosomal, 16S