Department of Chemical and Environmental Engineering, Malaysia-Japan International Institute of Technology, Universiti Teknologi Malaysia, Kuala Lumpur, Malaysia.
Graduate School of Science and Technology, University of Tsukuba, Tsukuba, Ibaraki, Japan.
Bioengineered. 2024 Dec;15(1):2314888. doi: 10.1080/21655979.2024.2314888. Epub 2024 Feb 20.
Cadmium (Cd) has become a severe issue in relatively low concentration and attracts expert attention due to its toxicity, accumulation, and biomagnification in living organisms. Cd does not have a biological role and causes serious health issues. Therefore, Cd pollutants should be reduced and removed from the environment. Microalgae have great potential for Cd absorption for waste treatment since they are more environmentally friendly than existing treatment methods and have strong metal sorption selectivity. This study evaluated the tolerance and ability of the microalga sp. P1 to remove Cd ions under acidic conditions and reveal mechanisms based on transcriptomics analysis. The results showed that sp. P1 had a high Cd tolerance that survived under the presence of Cd up to 100 µM, and IC, the half-maximal inhibitory concentration value, was 57.0 μM, calculated from the change in growth rate based on the chlorophyll content. Long-term Cd exposure affected the algal morphology and photosynthetic pigments of the alga. sp. P1 removed Cd with a maximum uptake of 1.55 mg g dry weight. Transcriptomic analysis revealed the upregulation of the expression of genes related to metal binding, such as metallothionein. Group A, Group B transporters and glutathione, were also found upregulated. While the downregulation of the genes were related to photosynthesis, mitochondria electron transport, ABC-2 transporter, polysaccharide metabolic process, and cell division. This research is the first study on heavy metal bioremediation using sp. P1 and provides a new potential microalga strain for heavy metal removal in wastewater.[Figure: see text]BP: Biological process; bZIP: Basic Leucine Zipper; CC: Cellular component; ccc1: Ca (II)-sensitive cross complementary 1; Cd: Cadmium; CDF: Cation diffusion facilitator; Chl: Chlorophyll; CTR: Cu TRansporter families; DAGs: Directed acyclic graphs; DEGs: Differentially expressed genes; DVR: Divinyl chlorophyllide, an 8-vinyl-reductase; FPN: FerroportinN; FTIR: Fourier transform infrared; FTR: Fe TRansporter; GO: Gene Ontology; IC50: Growth half maximal inhibitory concentration; ICP: Inductively coupled plasma; MF: molecular function; NRAMPs: Natural resistance-associated aacrophage proteins; OD: Optical density; RPKM: Reads Per Kilobase of Exon Per Million Reads Mapped; VIT1: Vacuolar iron transporter 1 families; ZIPs: Zrt-, Irt-like proteins.
镉（Cd）由于其毒性、在生物体内的积累和生物放大作用，即使在较低浓度下也已成为一个严重的问题，引起了专家的关注。Cd 没有生物作用，会导致严重的健康问题。因此，应该减少 Cd 污染物并将其从环境中去除。与现有的处理方法相比，微藻对 Cd 吸收具有很大的潜力，可用于废物处理，因为它们更环保，并且对金属具有很强的吸附选择性。本研究评估了微藻 sp. P1 在酸性条件下耐受和去除 Cd 离子的能力，并基于转录组学分析揭示了相关机制。结果表明，sp. P1 具有很高的 Cd 耐受性，在存在高达 100 μM Cd 的情况下仍能存活，根据叶绿素含量计算的生长率变化得出的半最大抑制浓度（IC）值为 57.0 μM。长期 Cd 暴露会影响藻类的形态和光合色素。sp. P1 对 Cd 的最大去除量为 1.55mg g 干重。转录组分析表明，与金属结合相关的基因，如金属硫蛋白，其表达上调。还发现 A 组、B 组转运蛋白和谷胱甘肽的表达上调。而与光合作用、线粒体电子传递、ABC-2 转运蛋白、多糖代谢过程和细胞分裂相关的基因表达下调。本研究是首次使用 sp. P1 进行重金属生物修复的研究，为废水中重金属去除提供了一种新的潜在微藻菌株。[图：见正文]BP：生物过程；bZIP：碱性亮氨酸拉链；CC：细胞成分；ccc1：钙（II）敏感交叉互补 1；Cd：镉；CDF：阳离子扩散促进剂；叶绿素；CTR：铜转运蛋白家族；DAGs：有向无环图；DEGs：差异表达基因；DVR：二氢叶啉 divinylchlorophyllide，8-乙烯还原酶；FPN：铁蛋白 FerroportinN；FTIR：傅里叶变换红外光谱；FTR：铁转运蛋白；GO：基因本体论；IC50：生长半最大抑制浓度；ICP：电感耦合等离子体；MF：分子功能；NRAMPs：天然抗性相关巨噬细胞蛋白；OD：光密度；RPKM：每百万读映射的外显子每千碱基读的reads；VIT1：液泡铁转运蛋白 1 家族；ZIPs：Zrt-Irt-like 蛋白。
