RESUMEN
Anaerobic digestion (AD) has long been studied as an effective environmental and economic strategy for treating matrices contaminated with recalcitrant pollutants. In the present work, we investigated the bioremediation potential of AD on organic waste contaminated with chlordecone (CLD), an organochlorine pesticide extensively used in the French West Indies and classified among the most persistent organic pollutants. Digestates from animal and plant origins were supplemented with CLD and incubated under methanogenic conditions for over 40 days. The redox potential and pH monitoring showed that methanogenic conditions were preserved during the entire incubation period despite the presence of CLD. In addition, the comparison of the total biogas generated from digestates with and without CLD demonstrated no adverse effects of CLD on biogas production. For the first time, a QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) extraction method, followed by GC-MS and LC-HRMS analyses, was developed to quantify CLD and its main known transformation products (TPs) in AD experiments. A decrease in CLD concentrations was evident to a greater extent under thermophilic conditions (55 °C) compared to mesophilic conditions (37.5 °C) (CLD removal of 85 % and 42 %, respectively, after 40 days of incubation). CLD degradation was confirmed by the detection and quantification of several TPs: 10-monohydroCLD (A1), two dihydroCLDs different from 2,8-dihydroCLD (A3), pentachloroindene (B1), tetrachloroindenes (B2, B3/B4), tetra- and tri-chloroindenecarboxylic acids (C1/C2, C3/C4). Determining TPs concentrations using the QuEChERS method provided an overview of CLD fate in AD. Overall, these results reveal that AD processes can efficiently degrade CLD into several TPs from A, B, and C families while maintaining satisfactory biogas production. They pave the way to developing a scaled-up AD process capable of treating CLD-contaminated organic wastes produced by farming, thus stopping any further transfer of CLD.
RESUMEN
Omega-3 polyunsaturated fatty acids (n-3 PUFAs) play an important role in the development, maintenance, and function of the brain. Dietary supplementation of n-3 PUFAs in neurological diseases has been a subject of particular interest in preventing cognitive deficits, and particularly in age-related neurodegeneration. Developing strategies for the efficient delivery of these lipids to the brain has presented a challenge in recent years. We recently reported the preparation of n-3 PUFA-rich nanoliposomes (NLs) from salmon lecithin, and demonstrated their neurotrophic effects in rat embryo cortical neurons. The objective of this study was to assess the ability of these NLs to deliver PUFAs in cellulo and in vivo (in mice). NLs were prepared using salmon lecithin rich in n-3 PUFAs (29.13%), and characterized with an average size of 107.90 ± 0.35 nm, a polydispersity index of 0.25 ± 0.01, and a negative particle-surface electrical charge (-50.4 ± 0.2 mV). Incubation of rat embryo cortical neurons with NLs led to a significant increase in docosahexaenoic acid (DHA) (51.5%, p < 0.01), as well as palmitic acid, and a small decrease in oleic acid after 72 h (12.2%, p < 0.05). Twenty mice on a standard diet received oral administration of NLs (12 mg/mouse/day; 5 days per week) for 8 weeks. Fatty acid profiles obtained via gas chromatography revealed significant increases in cortical levels of saturated, monounsaturated, and n-3 (docosahexaenoic acid,) and n-6 (docosapentaenoic acid and arachidonic acid) PUFAs. This was not the case for the hippocampus or in the liver. There were no effects on plasma lipid levels, and daily monitoring confirmed NL biocompatibility. These results demonstrate that NLs can be used for delivery of PUFAs to the brain. This study opens new research possibilities in the development of preventive as well as therapeutic strategies for age-related neurodegeneration.