Aug 2026· Preparative Biochemistry & Biotechnology· pp.
1-9
· 0 citations· 48 references
Medicine
Abstract
The textile industry generates large volumes of dye-laden effluents that pose risks to aquatic ecosystems and human health. This study evaluates the bioaccumulation of Reactive Black 5 (RB5) using Candida boidinii and Kluyveromyces marxianus yeast strains. Key operational parameters including initial pH, incubation time, dye concentration, and microbial growth were systematically investigated. In addition, the effects of low-cost agricultural wastes-carrot pomace (CP), industrial tea waste (ITW), and pumpkin pomace (PP)-as supplementary substrates were compared. Results showed that CP was the most effective substrate, with 100 g/L CP significantly enhancing RB5 removal. At pH 5.0 and 50 mg/L RB5, removal efficiencies reached 96.88% for C. boidinii and 81.76% for K. marxianus with CP, compared to 72.90% and 65.07% with PP. Although removal efficiency decreased at higher dye concentrations, the maximum dye uptake capacity (qm) increased with initial RB5 concentration, reaching 52.52 mg/g for C. boidinii and 33.23 mg/g for K. marxianus over the tested range (≈50-600 mg/L). To our knowledge, this is the first report demonstrating RB5 removal by these yeasts using CP as a low-cost substrate. Overall, CP significantly improves yeast-based RB5 bioaccumulation and represents a promising, sustainable option for treating dye-contaminated wastewater.
Converting industrial byproducts into functional adsorbents supports circular and sustainable approaches to water treatment. This study evaluated biochar derived from spent vetiver (
Chrysopogon zizanioides
) roots, a byproduct of the perfumery essential-oil industry, for the competitive adsorption of copper (Cu), cadmium (Cd), zinc (Zn), and lead (Pb). Vetiver root biochar produced at 500 °C for 60 min exhibited a high surface area of 308.2 m
2
/g and a yield of 53.8%. Batch adsorption experiments were performed in triplicate at a pH of 5.5 ± 0.2, in 0.1 M NaNO
3
, at 24 °C ± 2 °C, using 1% (w/v) biochar (10 g/L), with initial metal concentrations of 100 mg/L for each metal, along with a control. After 24 h, removal efficiencies reached 100% for Pb, 99.9% for Cu, 92.6% for Zn, and 77.0% for Cd. Adsorption was rapid, with nearly complete removal of Pb and Cu and approximately 60% removal of Zn and Cd within the first 30 min. High maximum adsorption capacities were achieved particularly for Pb, along with other tested metals, although competition in multi-metal systems influenced adsorption performance. Adsorption edge analysis and surface complexation modeling indicated that chemisorption was the dominant removal mechanism, supporting strong metal retention under the tested extraction conditions. Mild extraction released <3.5% of adsorbed metal, and TCLP/SPLP leachates were below U.S. EPA thresholds. Overall, these findings demonstrate that spent vetiver roots can be converted into high-performance biochar adsorbents, offering a sustainable, value-added strategy for heavy-metal remediation in water treatment systems.
S. Neve, Viravid Na Nagara, Zhiming Zhang et al.· Frontiers in Environmental C...· 0 citations
Cyanobacterial blooms are an increasing global concern due to the release of microcystins (MCs), potent hepatotoxins that threaten aquatic ecosystems, livestock, and human health. This study investigated the efficiency of low-cost natural adsorbents—rice straw (R), corn straw (C), and sawdust (S)—compared with commercial activated charcoal (AC) for the removal of microcystins from water sources in Upper Egypt. A total of 72 water samples were collected between June and September 2022 from rivers, irrigation canals, and wastewater channels in Sohag and Assiut governorates. Samples were analyzed for intra- and extracellular MCs using ultra-performance liquid chromatography (UPLC), while adsorbents were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), pH, moisture content, iodine number, and methylene blue adsorption. Results revealed mean total MC concentrations of 9.39, 3.18, and 11.70 µg/L in river, irrigation, and wastewater samples, respectively—exceeding the World Health Organization (WHO) guideline of 1 µg/L. Adsorption experiments demonstrated that AC exhibited the highest MC removal efficiencies (88.9% in acidified and 92.3% in neutral water), followed by sawdust (84–86.2%), corn straw (74.01–85.2%), and rice straw (75.4–74.8%). Sawdust and corn straw performed particularly well for extracellular MC removal, while AC was most effective for intracellular fractions. This study highlights the potential of agricultural by-products, particularly sawdust and corn straw, as sustainable, low-cost alternatives to activated charcoal for cyanotoxin removal. Their availability and efficiency support their application in water treatment systems without chemical pretreatment. These findings indicate that agricultural residues could serve as practical, low-cost adsorbents for mitigating cyanotoxin contamination in water, especially in resource-limited regions, while also promoting the beneficial reuse of agricultural waste.
Manal A. M. Mahmoud, Wafaa Kh. Kelini, Zakaria M. Zaky et al.· Sustainability· 0 citations
Abstract The manufacture and industrial use of dyes generate highly colored, often non-biodegradable effluents that pose serious environmental and public health risks.The aim of this study was to evaluate the capacity of ferula stems from the Saida region to serve as a biosorbent in the treatment of water synthetically contaminated with two dyes, Congo Red (CR) and Methylene Blue (MB). The results of XRD, FTIR, SEM, and EDS analyses confirm that ferula stems biomass has an amorphous lignocellulosic structure with functional groups and surface characteristics that favor dye adsorption. MB shows a higher adsorption capacity than CR, with a maximum retention of 33.83 mg/g versus 21.0 mg/g for CR. In competitive adsorption, the biomass showed a greater affinity for MB with 85% at higher concentrations. Adsorption data were well described by the Langmuir isotherm (R2 ≈ 0.95). These results demonstrate the promising applicability of Ferula biomass for treating dye-contaminated waters.
The extensive use of synthetic dyes in textiles generates highly coloured effluents, with reactive dyes posing major environmental challenges due to their stability and resistance to degradation. This study evaluates a sustainable bioremediation approach using white-rot fungi immobilized on agro-industrial residues for treating Remazol Turquoise Blue G-133 (RTB G-133). Two systems were tested: Pleurotus ostreatus on garlic peel-coffee husk (1:1 w/w) and Marasmiellus palmivorus on potato peel-cassava peel (7:3 w/w). Bioreactors operated under intermittent immersion for 12 days at dye concentrations of 100, 150, and 300 ppm with three treatments: fungal substrate (P1), substrate only (P2), and control (K). Maximum decolorization occurred at 100 ppm: 28.57% for P. ostreatus and 18.99% for M. palmivorus, while P2 achieved comparable removal (28.89% and 29.46%), suggesting that adsorption by the lignocellulosic substrate was the dominant mechanism; fungal hyphal colonization in P1 likely reduced substrate porosity and occupied adsorption sites, thereby limiting dye uptake relative to the uncolonized substrate. At 300 ppm, colour removal was negligible, highlighting concentration-dependent limitations. Enzyme assays confirmed ligninolytic activity in fungal treatments, with laccase ranging from 30-69 U/L and 31-61 U/L, and peroxidase up to 24.71 U/L and 16.88 U/L for P. ostreatus and M. palmivorus, respectively. Thin-layer chromatography and LC50 toxicity tests revealed structural modification and reduced toxicity in P1 samples compared to controls. These findings suggest that agro-waste-based fungal biocatalysts provide a cost-effective, eco-friendly strategy for dye wastewater treatment, though further optimization is required for higher dye loads.
S. H. Suhardi, Fina Wulandari Mardiyono, Devindha Permatasari et al.· IOP Conference Series: Earth...· 0 citations
Rice straw is a widely available agricultural residue with great potential for biofuels and bioproducts. However, the sustainability of its conversion remains uncertain due to the energy- and resource-intensive processing requirements. This study conducts a consequential life cycle assessment of four promising scenarios for the co-production of hydrogen and silica, each using different pretreatment strategies: (1) alkaline, (2) organosolv-alkaline, (3) acidic-alkaline, and (4) organosolv-alkaline coupled with nano-silica addition during fermentation. In all scenarios, silica was recovered from the alkaline pretreatment liquor, while cellulose-rich residues were subjected to enzymatic hydrolysis and dark fermentation to produce hydrogen. The results demonstrated that the environmental impacts, particularly from the pretreatment stage, outweigh the benefits of avoided products across all scenarios. While scenario 2 produced high experimental hydrogen yields (56.2 mL/g), it performed poorly in all damage categories. Despite the enhanced fermentation efficiency in scenario 4 (63.8 mL/g), the avoided products were still too low to offset the damages associated with organosolv pretreatment, and further impacts were created from adding nano-silica. In contrast, the least-burdensome pathway (scenario 3) with net impacts of 1.6 × 10-3 DALY, 3.3 × 10-6 species.yr, and 22.7 USD2013 per functional unit for the human health, ecosystem, and resource categories, respectively, did not show considerable differences compared to its corresponding single-hydrogen configuration. Sensitivity analysis identified opportunities to reduce the overall environmental impacts by enhancing the solid-to-liquid ratio and replacing fossil-based energy sources with renewable ones. These findings suggest that reducing pretreatment intensity and improving energy efficiency via process optimization and heat recovery may offer greater environmental benefits.
Shaghayegh Mojoodi, Fatemeh Al-Sadat Azarakhsh, D. Wall et al.· Journal of Environmental Man...· 0 citations
In response to growing environmental concerns from industrial and agricultural pollution, sustainable waste management strategies are increasingly important. This study presents a dual evaluation of spent activated carbon (AC) and nutrients recovered from gas adsorption filters, focusing on both fertilizer applications and the valorization of reactivated carbon. Adsorbent materials, such as AC impregnated with magnesium oxides, effectively capture harmful exhaust gases, but their disposal poses environmental challenges. Here, the chemical composition of spent AC was analyzed, and its potential as a soil amendment was assessed. Various nutrient recovery methods, including acidic, alkaline, and water-based extractions, were evaluated for their efficiency in retrieving nutrients from the spent adsorbent. The recovered solutions were chemically characterized based on Fe, K, and Mg concentrations. Results showed that alkaline extraction using 3% KOH yielded the highest in the recovered solution (Fe 7.45%, K 1.89%, Mg 1.22%), highlighting potential for producing nutrient-rich liquid fertilizers. Water-based extraction preserved the AC pore structure most effectively, achieving the highest BET surface area (118.18 m²/g), while acidic HCl treatment was associated with reduced surface area and pore volume, suggesting restricted pore accessibility and possible structural deterioration. Reducing adsorption performance. Germination assays revealed that water-washed filtrates promoted the greatest barley root elongation, whereas KOH filtrates exhibited inhibitory effects, reflecting differences in ionic composition. Economically, water-based regeneration was the most cost-effective (< 10% of virgin AC), while KOH treatment provided the dual benefit of reactivating AC for reuse and producing nutrient-rich solutions. Overall, the findings demonstrate that reused activated carbon coupled with recovered nutrients can enhance sustainable agriculture and support circular waste management systems.
Magdy A. Baiomy, Mayada E. Abdel Razek, O. Ahmed· Scientific Reports· 0 citations
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