Clostridium diolis shares high similarity based on 16S rRNA gene sequences and fatty acid composition with Clostridium beijerinckii. In this study, the taxonomic status of C. diolis was clarified using genomic and phenotypic approaches. High similarity was detected among C. diolis DSM 15410T, C. beijerinckii DSM 791T and NCTC 13035T, showing average nucleotide identity on blast and in silico DNA-DNA hybridization values over 97 and 85 %, respectively. Results of investigations for substrate utilization and enzyme activity displayed no striking differences between C. diolis DSM 15410T and C. beijerinckii JCM 1390T. Based on the results, we propose the reclassification of Clostridium diolis as a later heterotypic synonym of Clostridium beijerinckii. The type strain is ATCC 25752T (=CIP 104308T=DSM 791T=JCM 1390T=LMG 5716T=NCTC 13035T).
Keywords: Clostridium beijerinckii; Clostridium diolis; genome analysis; heterotypic synonym.