Actinomyces ruminis sp. nov., an obligately anaerobic bacterium isolated from the rumen of cattle

Abstract

An obligately anaerobic, rod-shaped, Gram-stain-positive, non-spore-forming, non-motile bacterial strain; designated as CtC72 T was isolated from the rumen of cattle. The 16S rRNA gene sequence similarity of less than 98.65% revealed the strain as a member of the genus Actinomyces, nearest to but distinct from Actinomyces qiguomingii DSM 106201 T , Actinomyces ruminicola DSM 27982 T , Actinomyces procaprae JCM 33484 T , Actinomyces succiniciruminis TISTR 2317, Actinomyces glycerinitolerans TISTR 2318. The low values of digital DNA-DNA hybridization (< 70%) and average nucleotide identity (< 95%) further highlighted the distinctive nature of strain CtC72 T from its closest relatives. The strain CtC72 T could grow at temperatures between 30-50°C (optimum 40°C), pH between 6.0-9.0 (optimum 7.5-8.0), and NaCl between 0-1.5% (optimum 0%). The strain hydrolysed cellulose and xylan and utilised a range of mono-, di-, and oligo-saccharides as a source of carbon and energy. Glucose fermentation resulted in acetic acid and formic acid as major metabolic products, while propionic acid, lactic acid, and ethanol as minor products along with CO 2 production. The DNA G + C content of strain CtC72 T was 68.40 (mol%, wet lab), and 68.05 (%, digital). Major cellular fatty acids (> 10%) were C 16:0 , C 18:1 ω9c, and C 18:1 ω9c DMA. Based on this data, we propose that strain CtC72 T be classi ed as a novel species, Actinomyces ruminis sp. nov., under the genus Actinomyces. The type strain is CtC72 T (= KCTC 15726 T = JCM 32641 T = MCC 3500 T ).

Description of Sporanaerobium hydrogeniformans gen. nov., sp. nov., an obligately anaerobic, hydrogen-producing bacterium isolated from Aravali hot spring in India

“…For phylogenetic analyses, the 16S rRNA gene sequences of closely related strains were downloaded from the NCBI GenBank database and aligned using MAFFT (Katoh et al 2019). The phylogenetic trees were constructed from the aligned sequences using Maximum-Likelihood (ML) method in W-IQ-TREE, Neighbor-Joining (NJ) method in the NGPhylogeny.fr server, and Maximum-Parsimony (MP) method in MEGA11, as described earlier (Lanjekar et al 2023). The 16S rRNA gene sequence of Thermoanaerobacter ethanolicus strain ATCC 31550 T (GenBank accession number: NR_044619) was used as an outgroup.…”

“…The substrate utilization pro les of the strain XHS1971 T were determined using the standard method described by Holdeman et al (1977) and Biolog AN MicroPlates™ (Biolog Catalog 1007) as per the manufacturer's protocol. The glucose fermentation products like gases and volatile and non-volatile fatty acids were determined using a 48 h grown culture in a PYG medium similar to the previous description (Lanjekar et al 2023). Other biochemical tests like production of catalase, oxidase, urease, and indole; reduction of nitrate and sulphate; and hydrolysis of arginine, threonine, aesculin, gelatin, starch glycogen, and bile tolerance were also performed in accordance with Holdeman et al (1977) The ability of the strain XHS1971 T to deconstruct the lignocellulosic biomass was also determined to decipher its potential role in bioenergy applications.…”

“…To investigate the taxonomic novelty of the strain XHS1971 T , phylogenomic, digital DNA-DNA hybridization (dDDH), Average Nucleotide Identity (ANI) and Average Amino Acid Identity (AAI) analyses were carried out and compared with the closest a liates as described previously (Sengupta et al 2022;Lanjekar et al 2023) The phylogenomic analysis of strain XHS1971 T with related strains of family Lachnospiraceae was performed using the Codon Tree method within PATRIC (Davis et al 2019), using PATRIC's Global Protein Families (PGFams) as homology groups. The aligned proteins and coding DNA from single-copy genes were used for RAxML analysis.…”