FIGURE 4.

Maximum-likelihood phylogenetic tree derived from 16S rRNA gene sequences, showing the phylogenetic positions of the isolated indigo-reducing bacteria. To construct the phylogenetic tree, the sequences were aligned with the sequences of neighboring species, and the consensus sequence was determined by CLUSTAL W (Thompson et al., 1994). The evolutionary history was inferred by using the maximum-likelihood method (Guindon and Gascuel, 2003) in MEGA 7 (Kumar et al., 2016). The evolutionary distance matrix was calculated by using Kimura’s two-parameter model (Kimura, 1980). Bold letters indicate the indigo-reducing bacteria. Although B. cohnii DSM 6307^T was not one of our isolates, strains belonging to this species that reduced indigo were isolated from indigo fermentation fluid. Bootstrap percentages (based on 1000 replicates) >50% are shown at branch points. Scale bars = 0.01 substitutions per nucleotide position.