Reclassification of non-type strain Clostridium pasteurianum NRRL B-598 as Clostridium beijerinckii NRRL B-598.

The complete genome sequence of non-type strain Clostridium pasteurianum NRRL B-598 was introduced last year; it is an oxygen tolerant, spore-forming, mesophilic heterofermentative bacterium with high hydrogen production and acetone-butanol fermentation ability. The basic genome statistics have shown its similarity to C. beijerinckii rather than the C. pasteurianum species. Here, we present a comparative analysis of the strain with several other complete clostridial genome sequences. Besides a 16S rRNA gene sequence comparison, digital DNA-DNA hybridization (dDDH) and phylogenomic analysis confirmed an inaccuracy of the taxonomic status of strain Clostridium pasteurianum NRRL B-598. Therefore, we suggest its reclassification to be Clostridium beijerinckii NRRL B-598. This is a specific strain and is not identical to other C. beijerinckii strains. This misclassification explains its unexpected behavior, different from other C. pasteurianum strains; it also permits better understanding of the bacterium for a future genetic manipulation that might increase its biofuel production potential.