Aminipila butyrica gen. nov., sp. nov., a strictly anaerobic, arginine-decomposing bacterium isolated from a methanogenic reactor of cattle waste.

A strictly anaerobic bacterial strain (FH042T) was isolated from a methanogenic reactor treating waste from cattle farms. Cells were stained Gram-positive, straight to gently curved rods with polar flagella. The strain was asaccharolytic. The strain fermented amino acids (l-arginine, l-lysine and l-serine) as growth substrates and produced acetate and butyrate. The optimum temperature for growth was 30 °C and the optimum pH was 6.1-6.8. Oxidase, catalase and nitrate-reducing activities were negative. Hydrogen sulfide was produced. The genomic DNA G+C content of strain FH042T was 44.7±0.2 mol%. The major cellular fatty acids were C18 : 1ω9c DMA, C17 : 2/C17 : 1ω9c (as summed feature), C16 : 0 DMA and C14 : 0. The cell-wall peptidoglycan contained meso-diaminopimelic acid as a diagnostic amino acid. The most closely related described species on the basis of 16S rRNA gene sequences was Anaerovorax odorimutans in the family XIII Incertae Sedis in the order Clostridiales of the class Clostridia with sequence similarity of 95.1 %. Based on the distinct differences in phylogenetic and phenotypic characteristics between strain FH042T and related species, Aminipila butyrica gen. nov., sp. nov. is proposed to accommodate the strain. Type strain is FH042T (=JCM 31555T=DSM 103574T).

Description of Anaerotignum aminivorans gen. nov., sp. nov., a strictly anaerobic, amino-acid-decomposing bacterium isolated from a methanogenic reactor, and reclassification of Clostridium propionicum, Clostridium neopropionicum and Clostridium lactatifermentans as species of the genus Anaerotignum.

A strictly anaerobic bacterial strain (SH021T) was isolated from a methanogenic reactor. Cells were Gram-stain-positive, motile, straight or slightly curved rods. The optimum temperature for growth was 35 °C, and the optimum pH was 6.1-7.7. The strain was asaccharolytic and utilized amino acids as growth substrates. The strain produced acetate and propionate from l-alanine and l-serine, and propionate and butyrate from l-threonine. Branched-chain amino acids (l-isoleucine, l-leucine and l-valine) were utilized weakly, and isovalerate or isobutyrate was produced. Strain SH021T utilized pyruvate and lactate, and converted them to acetate and propionate. The genomic DNA G+C content was 38.2 mol%. Compounds related to iso-C15 : 0 were detected as major components in the cellular fatty acids analysis. The diagnostic diamino acid of the cell-wall peptidoglycan was meso-diaminopimelic acid. On the basis of 16S rRNA gene sequences, the most closely related known species were Clostridium propionicum, Clostridium neopropionicum and Clostridium lactatifermentans in cluster XIVb of the class Clostridia. Based on the phylogenetic and phenotypic data, Anaerotignum aminivorans gen. nov., sp. nov. is proposed to accommodate strain SH021T (=JCM 31556T=DSM 103575T). For the three related species of the genus Clostridium, Anaerotignum propionicum comb. nov. (type strain DSM 1682T=JCM 1430T=ATCC 25522T=CCUG 9280T=NCIMB 10656T=VPI 5303T), Anaerotignum neopropionicum comb. nov. (type strain X4T=DSM 3847T=KCTC 15564T) and Anaerotignum lactatifermentans comb. nov. (type strain G17T=DSM 14214T=LMG 20954T) are proposed with emended descriptions of these species.