In this work, we designed at the level of microscale, subsurface flow wetlands planted with Typha latifolia, and used to remove diclofenac and naproxen from solutions that contained them. The wetlands were operated for 105 days with a hydraulic residence time (TRH) of 5 days. In these conditions, the removal efficiencies for diclofenac and naproxen were 98.4% and 97.7%, respectively. Moreover, we identified cultivable bacteria associated with the roots of plants exposed to either diclofenac or naproxen. We obtained 898 isolates that clustered in 9 morphotypes from the roots of Typha latifolia exposed to diclofenac, and 563 isolates grouped in 7 morphotypes, in the case of naproxen. All isolates were identified by 16S ribosomal sequencing. The BLASTn analysis indicated that 16 morphotypes showed an identity higher than 95% with the 16S rDNA gene of bacteria belonging to the genus Pseudomonas. Biochemical characterization based on plant growth-promoting activities suggests that bacteria contribute to plant growth in the wetland conditions. The results indicate that Typha latifolia and bacteria associated with their roots removed diclofenac and naproxen in subsurface flow wetlands.

Chlamydomonas reinhardtii is able to accumulate large amounts of triacylglycerides, the major feedstock for biodiesel production, when grown under stress conditions. In order to characterize gene transcripts induced under nitrogen, iron, and sulfur deprivation in C. reinhardtii; 583 expressed sequence tags (ESTs) were generated through a cDNA library. These sequences were subjected to contig assembly resulting in 30 contigs and 76 singletons. The comparison of the ESTs obtained with public databases allowed to assign putative functions to 66.7 % of the sequences. An important group of the identified genes are related to the lipid metabolic process. A phylogenetic analysis of these sequences identified five isoforms of diacylglycerol O-acyltransferase type 2 (DGAT-2). These genes were selected to measure their relative expression under these stress conditions by means of qRT-PCR. According to the results, the accumulation of DGTT1 mRNA increases considerably under nitrogen and iron inanition when compared to the other isoforms, which indicated that each isoform participates at different levels under each stress condition. These results can help to identify potential genes to be overexpressed by genetic engineering in C. reinhardtii.

Reducing the risk of the aquatic ecosystem’s contamination with organic substances such as pharmaceuticals is of great importance due to the toxicological effect of these substances on aquatic organisms. Therefore, the removal of pharmaceuticals and/or their metabolites frequently reported in industrial or municipal wastewaters require efficient processes that complement the conventional treatment systems; the constructed wetlands are an option. In this work, the removal efficiency of mixed diclofenac and naproxen was evaluated using a subsurface flow constructed wetland planted with cattail (Typha latifolia), operated during 100 days at a hydraulic residence time (HRT) of 3 days. Under these conditions, the diclofenac and naproxen removal efficiencies were 82.0% and 74.5%, respectively. The interaction between diclofenac and naproxen with cellulose, which is the major cell wall compound of higher plants, was computationally modeled at the PM6 semi-empirical level of theory and it was found that diclofenac and naproxen interact with cellulose via hydrogen bonds.   Resumen. Reducir el riesgo de contaminación de los ecosistemas acuáticos con sustancias orgánicas como los fármacos es de gran importancia debido al efecto toxicológico de estas sustancias para los organismos acuáticos. Por ello, la remoción de los fármacos y/o sus metabolitos frecuentemente reportados en aguas residuales industriales o municipales requiere de procesos eficientes que complementen los sistemas convencionales de tratamiento; los humedales construidos son una opción. En este trabajo, se evaluó la eficiencia de remoción de diclofenaco y de naproxeno en mezcla utilizando un humedal construido de flujo subsuperficial con plantas de tule (Typha latifolia), operado durante 100 días con un tiempo de residencia hidráulica (TRH) de 3 días. En estas condiciones, las eficiencias de remoción de diclofenaco y de naproxeno fueron de 82.0 % y 74.5 % respectivamente. La interacción entre diclofenaco y naproxeno con celulosa, que es el componente mayoritario de la pared celular de las plantas superiores, se modeló computacionalmente al nivel de teoría semiempírico con el método PM6, y se encontró que diclofenaco y naproxeno interactúan con celulosa mediante puentes de hidrógeno.