Figure 5.

The HIP degradation pathway shared by all of the studied steroid‐degrading bacteria. (A) The proposed HIP degradation pathway. Characterized or annotated enzymes from proteobacteria are marked in blue, and those from actinobacteria are marked in red. (B) The gene cluster for HIP degradation is widely present in steroid‐degrading actinobacteria and proteobacteria. The evolutionary history was inferred from 16S rRNA gene sequences using the maximum‐likelihood method in MEGA 7 (Kumar et al., 2016). Bootstrap values were calculated from 1,000 re‐samplings. Bacterial strains marked in black indicate that the aerobic steroid degradation capabilities were physiologically confirmed. Bacterial strains in red are steroid‐degrading denitrifiers. The steroid degradation capabilities of bacteria marked in grey remain to be experimentally confirmed. Gene nomenclature is based on that of Comamonas testosteroni strain TA441 (ORF1 ~ 33) and Mycobacterium tuberculosis strain H37Rv. Orthologous genes are marked with the same colours.