Biotechnology Program, Basic and Applied Science Institute, Egypt-Japan University of Science and Technology (E-JUST), New Borg El-Arab City, Alexandria, 21934, Egypt; Botany and Microbiology Department, Faculty of Science, Alexandria University, Alexandria, 21526, Egypt.
Biotechnology Program, Basic and Applied Science Institute, Egypt-Japan University of Science and Technology (E-JUST), New Borg El-Arab City, Alexandria, 21934, Egypt; Biochemistry Department, Faculty of Science, Ain Shams University, Cairo, 11566, Egypt.
J Environ Manage. 2024 Nov;370:122387. doi: 10.1016/j.jenvman.2024.122387. Epub 2024 Sep 7.
Microalgal tolerance to emerging contaminants (ECs) such as 1,4 dioxane (DXN) and its impact on phycoremediation performance, algal growth, biomolecules generated, and recycling the produced biomass for biochar production has been rarely reported. Hence, Chlorella vulgaris was cultivated in DXN-free wastewater (WW1) and 100 mg L DXN-laden wastewater (WW2) in 1-liter photobioreactors with an operating volume of 800 ml under controlled conditions: temperature (25 ± 1 °C), light intensity (351 μmol ms), and photoperiod (12 h light:12 h dark). Interestingly, this microalgal-based system achieved up to 32.79% removal efficiency of DXN in WW2. In addition, there was no significant difference in the removal of COD (90.6% and 86.8%) and NH-N (74.5% and 76.8%) between WW1 and WW2, respectively. Moreover, the variation in C. vulgaris growth, pigments, lipid, and carbohydrate contents between the two applied wastewaters was negligible. However, there was a significant increase in the protein yield upon exposure to DXN, suggesting the ability of C. vulgaris to secrete various antioxidant and degrading enzymes to detoxify the contaminant. These results were validated by FTIR, SEM, and EDX analysis of C. vulgaris biomass with and without DXN exposure. The harvested biomass was thermally treated at 350 °C for 60 min in an oxygen-free environment. The biochars generated from both algal systems were characterized by comparable morphologies and elemental profiles with sufficient C and N contents, indicating their applicability to enhance the soil properties. The economic evaluation of the combined phycoremediation/pyrolysis system demonstrated a net profit of 596 USD⋅y with a payback period of 6.2 years and fulfilled the objectives of several sustainable development goals (SDGs). This is the first study to point to C. vulgaris as a robust microalgal strain in remediating DXN-laden wastewater accompanied by the potential recyclability of the biomass produced for biochar production.
微藻对新兴污染物（ECs）如 1,4-二恶烷（DXN）的耐受性及其对光修复性能的影响、藻类生长、生成的生物分子以及回收产生的生物质用于生物炭生产的情况很少有报道。因此，在温度（25 ± 1°C）、光照强度（351 μmol·ms）和光周期（12 小时光照：12 小时黑暗）控制条件下，在 1 升光生物反应器中用 800ml 工作体积在无 DXN 的废水（WW1）和 100mg/L DXN 负荷废水（WW2）中培养普通小球藻。有趣的是，这种基于微藻的系统在 WW2 中实现了高达 32.79%的 DXN 去除效率。此外，WW1 和 WW2 之间 COD（90.6%和 86.8%）和 NH-N（74.5%和 76.8%）的去除率没有显著差异。此外，两种应用废水中普通小球藻的生长、色素、脂质和碳水化合物含量的变化可以忽略不计。然而，暴露于 DXN 后，蛋白质产量显著增加，表明普通小球藻能够分泌各种抗氧化和降解酶来解毒污染物。这些结果通过 FTIR、SEM 和 EDX 分析证明了在有无 DXN 暴露的情况下普通小球藻生物质的变化。收获的生物质在无氧环境中于 350°C 下热处理 60min。从两种藻类系统中生成的生物炭具有相似的形态和元素分布，且具有足够的 C 和 N 含量，表明它们可用于增强土壤特性。组合光修复/热解系统的经济评估表明，净利润为 596 美元·年，投资回收期为 6.2 年，并满足了几个可持续发展目标（SDGs）的目标。这是第一项指出普通小球藻是修复 DXN 负荷废水的稳健微藻菌株的研究，同时还指出了所产生的生物质回收用于生物炭生产的潜力。
