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.

Evaluation of the removal of pyrene and fluoranthene by Ochrobactrum anthropi, Fusarium sp. and their coculture.

Fluoranthene and pyrene are polycyclic aromatic hydrocarbons of high molecular weight that are recalcitrant and toxic to humans; therefore, their removal from the environment is crucial. From hydrocarbon-contaminated soil, 25 bacteria and 12 filamentous fungi capable of growth on pyrene and fluoranthene as the sole carbon and energy source were isolated. From these isolates, Ochrobactrum anthropi BPyF3 and Fusarium sp. FPyF1 were selected and identified because they grew quickly and abundantly in both hydrocarbons. Furthermore, O. anthropi BPyF3 and Fusarium sp. FPyF1 were most efficient at removing pyrene (50.39 and 51.32 %, respectively) and fluoranthene (49.85 and 49.36 %, respectively) from an initial concentration of 50 mg L(-1) after 7 days of incubation. Based on this and on the fact that there was no antagonism between the two microorganisms, a coculture composed of O. anthropi BPyF3 and Fusarium sp. FPyF1 was formed to remove fluoranthene and pyrene at an initial concentration of 100 mg L(-1) in a removal kinetic assay during 21 days. Fluoranthene removal by the coculture was higher (87.95 %) compared with removal from the individual cultures (68.95 % for Fusarium sp. FPyF1 and 64.59 % for O. anthropi BPyF3). In contrast, pyrene removal by the coculture (99.68 %) was similar to that obtained by the pure culture of Fusarium sp. FPyF1 (99.75 %). The kinetics of removal for both compounds was adjusted to a first-order model. This work demonstrates that the coculture formed by Fusarium sp. FPyF1 and O. anthropi BPyF3 has greater potential to remove fluoranthene than individual cultures; however, pyrene can be removed efficiently by Fusarium sp. FPyF1 alone.

Phylogenetic characterization of a corrosive consortium isolated from a sour gas pipeline.

Biocorrosion is a common problem in oil and gas industry facilities. Characterization of the microbial populations responsible for biocorrosion and the interactions between different microorganisms with metallic surfaces is required in order to implement efficient monitoring and control strategies. Denaturing gradient gel electrophoresis (DGGE) analysis was used to separate PCR products and sequence analysis revealed the bacterial composition of a consortium obtained from a sour gas pipeline in the Gulf of Mexico. Only one species of sulfate-reducing bacteria (SRB) was detected in this consortium. The rest of the population consisted of enteric bacteria with different characteristics and metabolic capabilities potentially related to biocorrosion. Therefore, several types of bacteria may be involved in biocorrosion arising from natural biofilms that develop in industrial facilities. The low abundance of the detected SRB was evidenced by environmental scanning electron microscopy (ESEM). In addition, the localized corrosion of pipeline steel in the presence of the consortium was clearly observed by ESEM after removing the adhered bacteria.