Nazari Negin, Jookar Kashi Fereshteh
Department of Cell and Molecular Biology, Faculty of Chemistry, University of Kashan, Kashan, Iran.
J Environ Manage. 2023 Jan 1;325(Pt A):116578. doi: 10.1016/j.jenvman.2022.116578. Epub 2022 Oct 27.
Recent advances in immobilized biologic systems for decolorizing azo dyes are gaining great attention due to microorganisms like bacteria and nanoparticles that could stimulate decolorization. Enhanced decolorization performance was observed in this study, indicating the great potential of the immobilized complex of bacterial cells and AgNPs as an alternative to the traditional biological processes to improve the performance of biological systems. The biodegradation and decolorization of Disperse Blue183 (DB 183) were investigated utilizing a novel combination of Enterococcus casseliflavus strain A mediated by silver nanoparticles synthesized by Marinospirillum alkaliphilum strain N in three different conditions. Ⅰ: free bacterial strain A (100% dye removal in 72 h), Ⅱ: immobilized bacterial strain A in Ca-Alg beads (100% dye removal in 15 h), and Ⅲ: immobilized bacterial strain A with silver nanoparticles (AgNPs) as support in Ca-Alg beads (100% dye removal in 9 h). The presence of bacterial cells and nanoparticles in Ca-Alg beads was assessed and proved by scanning electron microscope (SEM) and X-ray energy diffraction (EDX) analysis. Moreover, DB 183 and its decolorization metabolites were evaluated by applying UV-Vis, infrared spectroscopy (FTIR), and GC/MS, and the results showed that the dye was degraded. The antimicrobial effect, brine shrimp toxicity (BST) test, and mutagenicity assay in the presence and absence of metabolic activation (+S9/-S9) were run to assess DB 183 and metabolite obtained from biodegradation. The antimicrobial activity of DB 183 disappeared after treatment. Further, the results of the BST test determined that the dye has moderate biotoxicity (LC:0.064 mg/mL), and the after-treatment product was not toxic. According to the Ames test, DB 183 had mutagenicity effect (69-84%), and the metabolic activation increased the mutagenicity of the dye) 12-25%). However, the percentage mutagenicity of decolorization products decreased, ranging from 50 to 80% without activation (-S9) and 83-96% in present activation (+S9). This work used the immobilized bacterial cells and AgNPs Ca-Alg gel beads for the first time to introduce this kind of system as a suitable technique for rapid decolorization. Using this application enables a remarkable reduction in the time dedicated to the bioremediation of dyeing wastewater.
用于偶氮染料脱色的固定化生物系统的最新进展因细菌和纳米颗粒等微生物能够促进脱色而备受关注。本研究观察到脱色性能增强,表明细菌细胞与银纳米颗粒的固定化复合物作为传统生物过程的替代方法,在改善生物系统性能方面具有巨大潜力。利用嗜碱海螺旋菌菌株N合成的银纳米颗粒介导的新型格氏肠球菌菌株A组合,在三种不同条件下研究了分散蓝183(DB 183)的生物降解和脱色。Ⅰ:游离细菌菌株A(72小时内100%去除染料),Ⅱ:固定在钙藻酸盐珠中的细菌菌株A(15小时内100%去除染料),Ⅲ:以银纳米颗粒(AgNPs)为载体固定在钙藻酸盐珠中的细菌菌株A(9小时内100%去除染料)。通过扫描电子显微镜(SEM)和X射线能量衍射(EDX)分析评估并证明了钙藻酸盐珠中细菌细胞和纳米颗粒的存在。此外,通过紫外可见光谱、红外光谱(FTIR)和气相色谱/质谱联用仪对DB 183及其脱色代谢产物进行了评估,结果表明该染料被降解。在有无代谢活化(+S9/-S9)的情况下进行了抗菌效果、卤虫毒性(BST)试验和致突变性测定,以评估DB 183和生物降解获得的代谢产物。处理后DB 183的抗菌活性消失。此外,BST试验结果确定该染料具有中等生物毒性(LC:0.064 mg/mL),处理后的产物无毒。根据艾姆斯试验,DB 183有致突变性(69 - 84%),代谢活化增加了该染料的致突变性(12 - 25%)。然而,脱色产物的致突变性百分比降低,无活化(-S9)时为50%至80%,有活化(+S9)时为83%至96%。这项工作首次使用固定化细菌细胞和AgNPs钙藻酸盐凝胶珠,将这种系统作为一种快速脱色的合适技术引入。使用该应用能够显著减少用于印染废水生物修复的时间。