Hydrogen (H₂) as a clean fuel holds global potential and can be produced through bio-processes. To enhance bioH₂ yields, integrated systems have been proposed, combining dark fermentation (DF) of wastewater with a subsequent photofermentation (PF) stage involving purple non-sulfur (PNS) bacteria. Mixed cultures of PNS bacteria and their microbial ecology have been relatively understudied despite the known benefits of mixed cultures in industrial applications. The aim of this study was to obtain various mixed cultures of PNS bacteria under different environmental conditions during the enrichment stage. Four different mixed cultures were obtained (A, B, C, and D). However, in the H₂ production phase, only Consortium A, which had been enriched with malic acid as the carbon source, exposed to 32 W m⁻² of irradiance, and subjected to intermittent agitation, produced H₂ with a yield of 9.37 mmol H₂ g⁻¹ COD. The consortia enriched were a hybrid of PF and DF bacteria. Especially in Consortium A, Rhodopseudomonas palustris was the dominant organism, and various DF bacteria were positively associated with H₂ production, with their dominance comparable to that of PNS bacteria. Despite the reported low yields, optimizing environmental conditions for this culture could potentially enhance hydrogen production from DF effluents.

Senecio fistulosus, an endemic plant in Chile, is highly regarded for its medicinal properties and is popular in alternative medicine. It thrives even in polluted areas, like Puchuncaví Valley, Chile. Therefore, the study aimed to assess the impact of industrial pollution in Puchuncaví Valley, Chile, on the phytoconstituent content, as well as the antioxidant and cytotoxic activities, of S. fistulosus. Phenols, flavonoids, and anthraquinones content were measured, alongside the assessment of antioxidant activities. Additionally, a GC-MS analysis was conducted to profile the phytoconstituents, while the cytotoxic potential was evaluated in HT-29 and MCF-7 and cell line non-tumorigenic MCF-10. The Wild sample exhibited a greater concentration of phytoconstituents (0 to 169.48 mg·L⁻¹) compared to the Commercial control (0 to 95.38 mg·L⁻¹), directly correlating with its antioxidant activity. While the Wild species showed cytotoxic activity, the Commercial control demonstrated cytotoxic effects on MCF-10 and MCF-7. Noteworthy compounds identified were hexadecanoic acid (12.76 to 19.57% relative area) and (Z,Z,Z)-9,12,15-octadecatrienoic acid (18.36% relative area), with anticancer properties. In conclusion, the abiotic stress experienced by S. fistulosus led to higher phytoconstituent content and improved antioxidant activity when contrasted with the Commercial control. The Commercial species showed increased cytotoxic activity against both tumorigenic and non-tumorigenic cell lines.

Baccharis macraei Hook. & Arn (Asteraceae), commonly known as Vautro, is found in the coastal areas of central-southern Chile, including the industrial zone of Quintero-Puchuncaví, known for the contamination of its soils with heavy metals, which together with other factors generate abiotic stress in plant species, against which they present defensive mechanisms. For this reason, the objective was to evaluate the effect of abiotic stress generated by the proximity of B. macraei to the industrial complex by assessing the physiological and metabolic states reported by the extracts and compounds isolated from the species, as well as the photosynthetic capacity, metal content and production, and antioxidant activity and cytotoxicity against tumorigenic cell lines of the phytoconstituents. To this end, B. macraei was collected at two different distances from the industrial complex, observing that the closer the species is, the greater the concentration of copper in the soil, generating a decrease in the rate of electron transport in situ, but an increase in antioxidant activity with low cytotoxicity. This activity could be due to the presence of flavonoids such as Hispidulin, Cirsimaritina, and Isokaempferida, as well as monoterpenes, oxygenated and non-oxygenated sesquiterpenes identified in this study.