Fig 1.

Neighbor-joining tree based on 16S rRNA gene sequences, showing the relationship between the isolates (boldface type), their relatives, and other butanol-tolerant bacteria (shaded clusters). Due to the lack of sequences for butanol-tolerant Bacillus subtilis (13), Lactobacillus delbrueckii (10), and Pseudomonas putida (14) strains, as indicated by asterisks, their type strains are shown in the tree. The bootstrap values that were above 50% are shown at the nodes. Bar, 0.02 substitution per nucleotide position.