Summary auto-generated
Researchers isolated a novel anaerobic bacterium, strain NGAT, from a wool-scouring wastewater treatment facility in Uruguay. This Gram-negative, motile rod grows optimally at 55-60°C and ferments various peptides, carbohydrates, and organic acids, producing acetate, hydrogen, and carbon dioxide. A unique characteristic is its ability to use crotonate as an electron acceptor to oxidize amino acids like leucine. The bacterium reduces crotonate to butyrate and can also reduce thiosulfate, sulfur, and cystine. Genetic analysis using 16S rRNA gene sequencing showed 98% similarity to Anaerobaculum thermoterrenum, the only previously described species in this genus. However, DNA-DNA hybridization yielded only 40.8% similarity, and the G-C content differs by more than 3%, supporting classification as a distinct species. Phenotypic differences include motility (single flagellum), inability to ferment certain substrates like citrate, and different salt requirements. The authors propose this organism as Anaerobaculum mobile sp. nov. and provide an emended description of the genus.
Key findings
- Anaerobaculum mobile sp. nov. is a novel anaerobic, moderately thermophilic bacterium that uses crotonate exclusively as an electron acceptor to oxidize amino acids, a unique metabolic capability
- The bacterium was isolated from wool-scouring wastewater treatment, grows optimally at 55-60°C and pH 6.6-7.3, and ferments various peptides, carbohydrates, and organic acids
- Phylogenetic and molecular analysis confirmed NGAT as a new species distinct from A. thermoterrenum despite 98% 16S rRNA gene similarity, based on 40.8% DNA-DNA hybridization and 51.5 mol% G-C content
- Strain NGAT differs from A. thermoterrenum in motility, inability to ferment citrate and other substrates, and lower salt concentration requirements
This summary was generated automatically from the article PDF and is not part of the original publication. Refer to the PDF for the authoritative text.
Abstract
A novel anaerobic, moderately thermophilic, peptide-fermenting bacterium, strain NGA(T), was isolated from an anaerobic wool-scouring wastewater treatment lagoon. The cells were Gram-negative, straight rods of 0.5--1.0 x 2.0--4.0 microm, motile by means of a single flagellum. The DNA G+C content was 51.5 mol%. The optimum pH and temperature range for growth were 6.6--7.3 and 55--60 degrees C, respectively. The optimum NaCl concentration was 0.08 g l(-1). The bacterium fermented organic acids (malate, tartrate, pyruvate, glycerol and fumarate), a few carbohydrates (starch, glucose, fructose and gluconate), Casamino acids, tryptone and yeast extract. Carbohydrates and organic acids were converted to acetate, hydrogen and CO(2). The bacterium oxidized leucine to isovalerate with crotonate as an electron acceptor, but not in co-culture with Methanothermobacter thermoautotrophicus DSM 3720(T). Thiosulfate, sulfur and cystine were reduced to sulfide and crotonate was reduced to butyrate with glucose and tryptone-yeast extract as electron donors. Phylogenetic analysis of the 16S rRNA gene indicated that strain NGA(T) was related to Anaerobaculum thermoterrenum (98% similarity ), the only described species of the genus. The DNA--DNA hybridization value for strain NGA(T) and A. thermoterrenum ACM 5076(T) was 40.8%. On the basis of these results, strain NGA(T) is proposed as a novel species of the genus Anaerobaculum, namely Anaerobaculum mobile sp. nov. The type strain is NGA(T) (=DSM 13181(T)=ATCC BAA-54(T)).