Abstract：
Over decades, synthetic dyes have become increasingly dominated by azo dyes posing a significant environmental risk due to their toxicity. Microalgae-based systems may offer an alternative for treatment of azo dye effluents to conventional physical-chemical methods. Here, microalgae were tested to decolorize industrial azo dye wastewater (ADW). Chlorella sorokiniana showed the highest decolorization efficiency in a preliminary screening test. Subsequently, the optimization of the experimental design resulted in 70% decolorization in a photobioreactor. Tolerance of this strain was evidenced using multiple approaches (growth and chlorophyll content assays, scanning electron microscopy (SEM), and antioxidant level measurements). Raman microspectroscopy was employed for the quantification of ADW-specific compounds accumulated by the microalgal biomass. Finally, RNA-seq revealed the transcriptome profile of C. sorokiniana exposed to ADW for 72 h. Activated DNA repair and primary metabolism provided sufficient energy for microalgal growth to overcome the adverse toxic conditions. Furthermore, several transporter genes, oxidoreductases-, and glycosyltransferases-encoding genes were upregulated to effectively sequestrate and detoxify the ADW. This work demonstrates the potential utilization of C. sorokiniana as a tolerant strain for industrial wastewater treatment, emphasizing the regulation of its molecular mechanisms to cope with unfavorable growth conditions.
摘要：
几十年来，合成染料越来越多地由偶氮染料主导，由于它们的毒性而对环境构成重大风险。基于微藻的系统可以为处理偶氮染料流出物提供常规物理化学方法的替代方案。这里,试验了微藻对工业偶氮染料废水(ADW)的脱色效果。小球藻在初步筛选试验中显示出最高的脱色效率。随后，实验设计的优化导致70％的脱色在光生物反应器。使用多种方法证明了该菌株的耐受性（生长和叶绿素含量测定，扫描电子显微镜（SEM），和抗氧化剂水平测量)。拉曼显微光谱法用于定量由微藻生物质积累的ADW特异性化合物。最后,RNA-seq揭示了暴露于ADW72小时的索罗基梭菌的转录组谱。激活的DNA修复和初级代谢为微藻生长提供了足够的能量以克服不利的毒性条件。此外，几个转运基因，氧化还原酶-,和糖基转移酶编码基因被上调以有效地螯合和解毒ADW。这项工作证明了作为工业废水处理的耐性菌株的索氏梭菌的潜在利用。强调其分子机制的调节，以应对不利的生长条件。
