Pyrene was obtained from Sigma-Aldrich .
Beef extract medium (BEM) used for strain culture contained (g/L)
3 beef extracts, 10 peptone and 5 NaCl. Mineral salt medium
(MSM) used as the degradation medium consisted of (mg/L) 50
K2HPO4, 30 KH2PO4, 10 MgSO4 7H2O and 50 C6H5Na3O7 2H2O,
and pH was adjusted to 7.0. All the mediums were previously
sterilized in an autoclave at 121 °C for 30 min.