Search

Hexavalent chromium removal from the environment remains a crucial worldwide challenge. To address this issue, microbiological approaches are amongst the straightforward strategies that rely mainly on the bacteria's and fungi's survival mechanisms upon exposure to toxic metals, such as reduction, e flux system, uptake, and biosorption. In this work, scanning electron microscopy, energy-dispersive X-ray spectrophotometry, Fourier transform infrared spectroscopy, and zeta potential measurements were used to investigate the ability of chromium adsorption by Bacillus licheniformis, Bacillus megaterium, Byssochlamys sp., and Candida maltosa strains isolated from tannery wastewater. Scanning electron microscopy combined with energy dispersive X-ray spectroscopy revealed alterations in the cells treated with hexavalent chromium. When exposed to 50 mg/L Cr6+, Bacillus licheniformis and Candida maltosa cells become rough, extracellular secretions are reduced in Bacillus megaterium, and Byssochlamys sp. cells are tightly bound and exhibit the greatestCr weight percentage. In-depth analysis of Fourier transforminfrared spectra of control and Cr-treated cells unveiled Cr-microbial interactions involving proteins, lipids, amino acids, and carbohydrates. These findings were supported by zeta potential measurements highlighting significant variations in charge after treatment with Cr(VI) with an adsorption limit of 100 mg/L Cr6+ for all the strains. Byssochlamys sp. showed the best performance in Cr adsorption, making it the most promising candidate for treating Cr-laden wastewater. [ABSTRACT FROM AUTHOR]

Sandy beaches along the North African Mediterranean coast face significant challenges due to accumulating human-made debris (marine litter) and natural debris (beach wrack). Addressing these issues requires awareness of pollution and the ecological relevance of beach wrack, along with stakeholder involvement. This study quantifies beach litter pollution and identifies sources in Tunisia, Morocco, and Egypt, serving as a basis for ecosystem service assessments and further integration into the implementation of mitigation measures. High levels of plastic litter were found, ranging from 1565 to 7778 pieces per 100 m of beach length. Shoreline activities, tourism, and poor waste management were identified as the main sources of litter, with single-use plastics accounting for 41.1% of the debris. Further objectives include providing a list of suitable ecosystem services and developing management scenarios. Local stakeholders' perceptions of the impact of marine litter and beach wrack on ecosystem services were assessed using a scenario approach and different formats (i.e., stakeholder workshop, interviews, teaching). Stakeholders highlighted the negative impact of marine litter on cultural services, while beach wrack was perceived positively for regulating and maintenance services. This approach enhances awareness, interest, and knowledge in data-scarce regions, serving as a valuable tool for stakeholder engagement, elicitation of stakeholder knowledge, and teaching (i.e., learning tool). Limitations include the subjectivity of the results, limited participant reach, and dependence on stakeholder knowledge. Integrating stakeholder-based ecosystem service assessments into measure planning and decision making is essential for effective litter management and beach conservation efforts. [ABSTRACT FROM AUTHOR]

This study aims to use contaminated soil with leachate to select autochthonous fungi that are able to bioremediate three types of leachate, (Young (YL), Intermediate (IL) and Old (OL)). Eleven fungal species were isolated via the enrichment method using the leachate as the sole source of carbon and energy. The isolates were evaluated for their ability to grow and remove organic pollutants at 100%, 50% and 25% (v/v) of leachate in both solid and liquid cultures that were spiked with malt extract. The results indicated that only three fungi, Aspergillus flavus (A. flavus-LC106118), Aspergillus niger (A. niger-KT192262) and Fusarium solani (F. solani-KX349467) showed significantly high capacity to grow on leachate, with maximum radial growth rates (Gr) of 7.5 mm, 4.7 mm, and 5.3 mm, respectively. In addition, 34%, 22%, and 27%, respectively of COD removal rates were obtained at 25% concentration in YL. A. flavus was the most tolerant fungus against landfill leachate, followed by F. solani, and finally A. niger. Therefore, these three fungi are good candidates for leachate bioremediation. However, for a better remediation, the combined effects of different types of fungi and leachates on the fungal growth need to be considered during the fungi selection. [ABSTRACT FROM AUTHOR]