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The main actinobacterial genera able to degrade polycyclic aromatic hydrocarbons (PAHs) include Mycobacterium , Nocardia , Rhodococcus , and Gordonia . However, it is unknown if other actinobacterial genera can degrade PAHs. In this work, three actinobacteria strains that utilize PAHs as the sole source of carbon and energy, were isolate and termed Amycolatopsis sp. Poz14, Gordonia sp. Poz20, and Rhodococcus sp. Poz54. The strains use low-molecular-weight (LMW; naphthalene and anthracene) and high-molecular-weight (HMW; pyrene and fluoranthene) PAHs at 50 mg L −1 as the sole carbon and energy sources; except Amycolatopsis sp. Poz14 which tolerate up to 200 mg L −1 . Amycolatopsis sp. Poz14 exhibited higher degradation percentages for LMW-PAH than HMW-PAH, from 100% for naphthalene, 37.87% for anthracene, 25.10% for pyrene, and 18.18% for fluoranthene within 45-day. Degradation efficiency of PAHs by Amycolatopsis sp. Poz14 improved by adding tween 20 to 1000 mg L −1 . Moreover, degradation kinetics of binary mixtures of PAHs were conducted, Amycolatopsis sp. Poz14 used both PAHs from the beginning of the kinetics, and degradation efficiencies in binary mixtures were better than those achieved in single PAH. To the best of our knowledge, this is the first report involving to genus Amycolatopsis in the degradation of LMW- and HMW-PAHs.

Increasing contamination of soil and groundwater with benzene, toluene, and xylene (BTX) due to activities of the chemical and oil refinery industry has caused serious environmental damage. Efficient methods are required to isolate and degrade them. Microorganisms associated with rhizosphere soil are considered efficient agents to remediate hydrocarbon contamination. In this study, we obtained a stabilized bacterial consortium from the rhizosphere soil of Cyperus sp. grown in a petroleum-contaminated field in Southern Mexico. This consortium was able to completely degrade BTX in 14 days. Bacteria isolated from the consortium were identified by 16S rRNA gene sequence analysis as Ralstonia insidiosa, Cellulomonas hominis, Burkholderia kururiensis, and Serratia marcescens. The BTX-degradation capacity of the bacterial consortium was confirmed by the detection of genes pheA, todC1, and xylM, which encoded phenol hydroxylase, toluene 1,2-dioxygenase, and xylene monooxygenase, respectively. Our results demonstrate feasibility of BTX biodegradation by indigenous bacteria that might be used for soil remediation in Southern Mexico.