Laboratory of Analytical Chemistry and Applied Ecochemistry, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000, Ghent, Belgium; UNESCO-IHE Institute for Water Education, 2601, DA, Delft, The Netherlands.
UNESCO-IHE Institute for Water Education, 2601, DA, Delft, The Netherlands.
Water Res. 2020 Apr 1;172:115522. doi: 10.1016/j.watres.2020.115522. Epub 2020 Jan 22.
Selenium (Se) and zinc (Zn) are essential micronutrients that are often lacking in the diet of humans and animals, leading to deficiency diseases. Lemna and Azolla are two aquatic plants with a substantial protein content, which offer the possibility of utilizing them to remove Se and Zn from (waste)water while producing micronutrient-enriched dietary proteins and fertilizers. In this study, we explored interaction effects occurring between Se and Zn when these micronutrients are taken up by Azolla and Lemna. The two aquatic plants were grown on hydroponic cultures containing 0-5.0 mg/L of Se (Se(IV) or Se(VI)) and Zn. The Se and Zn content of the plants, growth indicators, bioconcentration factor (BCF) and Se/Zn removal efficiency from the water phase were evaluated. The results demonstrated that Se(IV) is more toxic than Se(VI) for both plant species, as evidenced by the remarkable decrease of biomass content and root length when exposed to Se(IV). Both aquatic plants took up around 10 times more Se(IV) than Se(VI) from the medium. Moreover, the Se accumulation and removal efficiency increased by 66-99% for Se(IV) and by 34-59% for Se(VI) in Lemna when increasing Zn dosage from 0 to 5.0 mg/L in the medium, whereas it declined by 13-26% for Se(IV) and 21-35% for Se(VI) in Azolla, suggesting a synergetic effect in Lemna, but an antagonistic effect in Azolla. The maximum BCF of Se in Lemna and Azolla were 507 and 667, respectively. The protein content in freeze-dried Lemna and Azolla was approximately 17%. The high tolerance and accumulation of Se and Zn in Lemna and Azolla, combined with their rapid growth, high protein content and transformation of inorganic to organic Se species upon Se(IV) exposure make Lemna and Azolla potential candidates for the production of Se(IV)- and Zn-enriched biomass that can be used as crop fertilizers or protein-rich food/feed supplements or ingredients. Accordingly, by growing the Azolla and Lemna on wastewater, a high-value product can be produced from wastewater while recovering resources.
硒（Se）和锌（Zn）是人体和动物饮食中经常缺乏的必需微量元素，导致缺乏症。浮萍和满江红是两种具有大量蛋白质含量的水生植物，它们提供了利用它们从（废水）水中去除 Se 和 Zn 的可能性，同时生产富含微量营养素的膳食蛋白质和肥料。在这项研究中，我们探讨了当这些微量元素被满江红和浮萍吸收时，它们之间发生的相互作用效应。这两种水生植物在含有 0-5.0 mg/L 的 Se（Se(IV) 或 Se(VI)）和 Zn 的水培培养物中生长。评估了植物的 Se 和 Zn 含量、生长指标、生物浓缩因子（BCF）和从水相中去除 Se/Zn 的效率。结果表明，Se(IV) 对两种植物的毒性都大于 Se(VI)，因为暴露于 Se(IV)时生物量含量和根长显著下降。两种水生植物从培养基中吸收的 Se(IV) 比 Se(VI)多约 10 倍。此外，当培养基中 Zn 剂量从 0 增加到 5.0 mg/L 时，满江红中 Se 的积累和去除效率分别增加了 66-99%和 34-59%，而 Se(IV) 下降了 13-26%和 Se(VI)下降了 21-35%，表明在 Lemna 中存在协同作用，但在 Azolla 中存在拮抗作用。Lemna 和 Azolla 中 Se 的最大 BCF 分别为 507 和 667。冻干的 Lemna 和 Azolla 的蛋白质含量约为 17%。Lemna 和 Azolla 对 Se 和 Zn 的高耐受性和积累，加上它们的快速生长、高蛋白含量以及在 Se(IV)暴露下将无机 Se 转化为有机 Se 物种，使 Lemna 和 Azolla 成为生产富含 Se(IV)和 Zn 的生物质的潜在候选物，可作为作物肥料或富含蛋白质的食品/饲料补充剂或成分。因此，通过在废水上种植满江红和浮萍，可以从废水中生产高价值产品，同时回收资源。
