Global NEST Journal

The circular economy approach represents a strategy to optimize product lifecycles, thus improving the sustainability of consumption patterns. In the European Union a recent legislative proposal has addressed this concept by promoting waste prevention and re-use as well as extensive recovery of materials. Such approach is particularly interesting for the management of Waste Electrical and Electronic Equipment (WEEE), that is regarded as an urban stock of different metals, and in particular of both precious metals and rare earth elements. The recovery of metals is the main focus of WEEE management strategies and, more recently, it has been receiving a great deal of attention, especially due to the continuously increasing production of this waste stream. However, great room for improvements can still be recognised to ensure the overall sustainability of WEEE management. The present work discusses both the current needs and the main challenges regarding WEEE management in a circular economy perspective. To this end, WEEE generation trend and composition is provided and the legislative framework for its handling is overviewed, in order to point out future perspectives to develop a more sustainable management approach of this waste.

Plant nanotoxicology is an emerging and less-explored area of research for the plant stress biologists. The present study assesses the toxicity of bulk-CuO and nano-CuO (size <50 nm and surface area = 29 m² g^-1) on maize (Zea mays cv. hybrids triple white Hi Tech.) seedlings. Five successive levels of stress (25, 50, 100, 150 and 200 mg L^-1) suspensions of CuO and CuONP were imposed and seedling growth performance was studied along control at 8 days of experiment. Modulation of enzymatic antioxidants (SOD, CAT, APX and POD) and non-enzymatic antioxidants (total phenolics and total flavonoids) activities under both-CuO stresses were investigated in detail to get an overview of their-stress response of maize. Seed germination was completely stopped under 150 and 200 mg L^-1CuONP. Generally, CuONP stress was most violent and 100 mg L^-1CuONP showed the same or more drastic effect in 150 and 200 Cu bulk. Photosynthetic pigments, shoot and root lengths reduced under both stresses by about 50% of control. Soluble proteins and total antioxidants increased gradually till it reached about 200% of control at 150 mg L^-1CuO and about 200-300% at 100 mg L^-1CuONP. In addition, increased reducing power activity coupled with both stresses which reached to 400% of control at 150 mg L^-1CuO and 100 mg L^-1CuONP. Moreover, superoxide dismutase increased by 800% of control at 100 mg. L^-1CuONP.

Plant-associated microorganisms, especially endophytic fungi, represent an untapped resource for the discovery of biologically active natural products. The objectives of this study were to isolate, identify endophytic fungi, and produce their bioactive metabolites from the leaves of two varieties of Egyptian artichoke namely: French Hyrious and Egyptian Baladi. In addition, assess of their total antioxidant capacity (TAC), total phenolic content (TPC) and total flavonoid content (TFC). The results of this novel study show a total of 35 endophytic fungal species belonging to 14 genera were isolated from both artichoke leaves with gross total counts of colonizing endophytic fungi ranged from 71 to 123 cfu which is matching 78.89% to 136.67% of colonization frequency. All taxa recovered were assigned to Ascomycetes. In addition, there is high species richness and diversity indices of endophytic filamentous fungi in the leaves Baladi Artichoke as compared to its French rival.  Alternaria alternata were found to be the most frequently isolated dominant species. The TAC, TPC and TFC of the fungal cultures ranged from 163 to 681 mgAAE/gDW, 10.38 to 40.30 mgGAE/ gDW, and 13.92 to 173.55 mgQE/gDW, respectively. Furthermore, LC-ESI-MS/MS confirmed the presence of 1,3-dicaffeoylquinic acid and 1,5-dicaffeoylquinic acid in the methanolic extract of A. alternata. Hence, this novel study suggested that the metabolites produced by endophytic fungi associated with Egyptian artichoke could be explored as an economic and potential natural resources with diverse pharmaceutical and biological activities.

In this study, a new technology was introduced to monitor the odor occurrence situation at the remote site in real time and the technology to reduce sewage odor by using microbial deodorant. Long-term monitoring and full-scale test was carried out to investigate the odor concentration in the combined sewer using the real - time odor monitoring device which consist of 3 odor sensors with the wireless communication technique, and to investigate the effect of the microbial deodorant on the reduction of sewer odor. The odor monitoring device, which was fabricated using metal oxide semiconductor sensors and code division multi access communication technique, was installed at three sites of the gravity-flow type combined sewer (depth 3m and width 5m) in Gangnam, Seoul. Odor monitoring in field was carried out at the interval of 10 minutes for 304 days over the autumn, winter and summer. The measured results were transmitted to Woosong odor research center about 100km away from the site. The measured sensor value was converted to olfactory odor concentration by the co-relation equation of the sensor value and the olfactory odor concentration. As the monitoring results, more than 40,000 sewage odor data were obtained. The average odor concentration of raw sewage in combined sewer was 464 OUk, which was 321 OUk in winter and 412 OUk in autumn and 659 OUk in summer. The commercial microbial deodorant used in this study was the mixture culture of 48 microbial strains, and the microbial deodorant of 1 m3 d-1 to 2 m3 d-1 was mixed with raw sewage at the 1.5 km upstream of the site where odor complaints occurred. As the experimental results, the average odor concentration of sewage mixed with microbial deodorant was 113 OUk, which was 102 OUk in winter and 298 OUk in autumn and 153 OUk in summer. It was estimated that the odor reduction effect of sewer odor by microbial deodorant is about 74%.