Evaluation of Amycolaptosis sp. Ver12 as a potential degrader of benzo(b)fluoranthene.

Benzo(b)fluoranthene (BbF) is a polycyclic aromatic hydrocarbon (PAH) with five fused benzene rings; it is a highly recalcitrant compound and a priority environmental pollutant due to its detrimental effects on human health and the survival of wild animals. Biodegradation of BbF by microorganisms is an attractive alternative, and few studies have been focused on this issue. In this work, bacteria with the ability to degrade BbF were isolated and selected. The capability of the isolates to tolerate concentrations of 50 and 75 mg l-1 of BbF in liquid medium was evaluated. The selected isolates were identified by the 16S rRNA gene sequencing as belonging to Bacillus, Gordonia, Pseudomonas, Rhodococcus, Ochrobactrum, and Amycolatopsis. All isolates were tolerant and grew at the BbF concentrations tested, some isolates were more competitive than others, and the most prominent was Amycolatopsis sp. Ver12, which removed 47% of BbF, furthermore, with the addition of yeast extract, removed 59% of the compound. In summary, the report shows that Amycolatopsis sp. Ver12 can degrade BbF efficiently and could be considered for bioremediation of BbF-contaminated environments.

Utilization of naproxen by Amycolatopsis sp. Poz 14 and detection of the enzymes involved in the degradation metabolic pathway.

The pollution of aquatic environments by drugs is a problem for which scarce research has been conducted in regards of their removal. Amycolatopsis sp. Poz 14 presents the ability to biotransformation naphthalene at high efficiency, therefore, in this work this bacterium was proposed as an assimilator of naproxen and carbamazepine. Growth curves at different concentrations of naproxen and carbamazepine showed that Amycolatopsis sp. Poz 14 is able to utilize these drugs at a concentration of 50 mg L-1 as a source of carbon and energy. At higher concentrations, the bacterial growth was inhibited. The transformation kinetics of naproxen showed the total elimination of the compound in 18 days, but carbamazepine was only eliminated in 19.9%. The supplementation with cometabolites such as yeast extract and naphthalene (structure similar to naproxen) at 50 mg L-1, showed that the yeast extract shortened the naproxen elimination to 6 days and reached a higher global consumption rate compared to the naphthalene cometabolite. The biotransformation of carbamazepine was not improved by the addition of cometabolites. The partial sequencing of the genome of Amycolatopsis sp. Poz 14 detected genes encoding putative enzymes for the degradation of cyclic aromatic compounds and the activities of aromatic monooxygenase, catechol 1,2-dioxygenase and gentisate 1,2-dioxygenase exhibited their involving in the naproxen biodegradation. The HPLC-MS analysis detected the 5-methoxysalicylic acid at the end of the biotransformation kinetics. This work demonstrates that Amycolatopsis sp. Poz 14 utilizes naproxen and transforms it to 5-methoxysalicylic acid which is the initial compound for the catechol and gentisic acid metabolic pathway.