Isolation and characterization of Sporomusa carbonis sp. nov.: a carboxydotrophic hydrogenogen in the genus of Sporomusa isolated from a charcoal-burning pile

A Gram-negative bacterial strain, designated ACPt^T, was isolated from the top of the covering soil of an active charcoal-burning pile. The cells of ACPt^T were strictly anaerobic, rod-shaped and grew optimally at 40 °C and pH 7. The substrates ribose, glucose, sucrose, raffinose, melezitose, pyruvate, vanillate, syringate, methanol and CO were utilized for growth. Phylogenomic analysis of the 4.1 Mb genome showed that strain ACPt^T represented a novel species of the genus <i>Sporomusa</i>. The most closely related species to ACPt^T was <i>Sporomusa malonica,</i> with an average amino acid identity of 80.1%. The genome of ACPt^T encoded cytochromes, ubiquinones, the Wood-Ljungdahl gene cluster and an Rnf complex, which were identified as common features of all <i>Sporomusa</i> type strains. However, strain ACPt^T did not ferment H₂+CO₂ via acetogenesis as other <i>Sporomusa</i> species but employed the metabolism of a carboxydotrophic hydrogenogen, converting CO to H₂+CO₂. Based on the genomic, morphological and physiological features presented in this study, strain ACPt^T is proposed as a novel species in the genus <i>Sporomusa,</i> with the name <i>Sporomusa carbonis</i> sp. nov. (DSM 116159^T and CCOS 2105^T).