Rarefaction analyses of catabolic gene clone libraries showed that coverage of the libraries was sufficient and their diversities were fully covered. This was evident in case of 3-IPC
2,3-dioxygenase and subfamily I.2.A C23O genes, due to the low number of sequence variants detected (data not shown), but it was also obvious in the case of subfamily I.2.C C23O genes (Fig. S2b).