Departamento de Química, Faculdade de Filosofia Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, 14040-901, Ribeirão Preto, SP, Brazil.
Departamento de Bioquímica e Microbiologia, Instituto de Biociências, Universidade Estadual de São Paulo (Unesp), Av. 24-A, 1515, 13506-900, Rio Claro, SP, Brazil.
Ecotoxicol Environ Saf. 2019 Nov 15;183:109484. doi: 10.1016/j.ecoenv.2019.109484. Epub 2019 Aug 6.
This work evaluated the degradation of the Acid Blue 161 and Procion Red MX-5B dyes in a binary solution by the filamentous fungus Aspergillus terreus and the yeast Saccharomyces cerevisiae in systems with and without electrochemical oxidation as the pretreatment process. UV-Vis spectrophotometry, high-performance liquid chromatography with (HPLC), Fourier transform infrared (FT-IR) spectroscopy and Salmonella/microsome assay (Ames test) were applied towards the degradation analysis of the dyes. Adsorption tests with white clay immobilized on alginate were also conducted after the discoloration treatments to remove intermediate metabolites formed during the degradation of the dye molecules. The discoloration treatments led to the complete color removal of the solutions in all the systems tested. The clay demonstrated affinity for the metabolites formed after discoloration treatments, the removal rates were variable, but the all systems has proved efficient. The Salmonella/microsome assay (Ames test) with strains TA98 and TA100 in the absence and presence of exogenous metabolism (S9 microsomal system, Moltox) revealed that the initial molecules and by-products of the metabolism of the dyes were direct mutagens. The electrochemical/A. terreus/clay system was able to discolor the solutions and transform the direct mutagens into non-mutagenic compounds in addition to reducing the mutagenic potency of the pro-mutagens to the Salmonella strain TA100/S9, which demonstrates the high efficiency of this system with regard to discoloring and degrading azo dye molecules and their by-products. Therefore, this study showed that although not having standard treatment system for this type of pollutant, the combination of treatments can be considered promising. The use of electrochemical oxidation along with microbiological treatment may lead to the degradation and mineralization of these compounds, reducing or eliminating the environmental impact caused by the improper disposal of these dyes in aquatic environments.
这项工作评估了丝状真菌 Aspergillus terreus 和酵母 Saccharomyces cerevisiae 在有和没有电化学氧化预处理过程的二元体系中对酸性蓝 161 和 Procion 红 MX-5B 染料的降解情况。采用紫外可见分光光度法、高效液相色谱（HPLC）、傅里叶变换红外（FT-IR）光谱和沙门氏菌/微粒体测定法（Ames 试验）对染料的降解进行了分析。在进行脱色处理后，还进行了用藻酸盐固定化白土的吸附试验，以去除在染料分子降解过程中形成的中间代谢物。在所有测试的系统中，脱色处理导致溶液完全脱色。粘土对脱色处理后形成的代谢物具有亲和力，去除率各不相同，但所有系统都被证明是有效的。在没有和存在外源性代谢物（S9 微粒体系统，Moltox）的情况下，用菌株 TA98 和 TA100 进行的沙门氏菌/微粒体测定法（Ames 试验）表明，初始分子和染料代谢的产物是直接诱变剂。电化学/A. terreus/粘土系统不仅能够使溶液脱色，而且能够将直接诱变剂转化为非诱变化合物，同时还降低了促突变剂对沙门氏菌 TA100/S9 的诱变能力，这表明该系统在脱色和降解偶氮染料分子及其产物方面具有很高的效率。因此，本研究表明，尽管没有针对这种类型污染物的标准处理系统，但联合处理可以被认为是有前途的。电化学氧化与微生物处理的结合可能会导致这些化合物的降解和矿化，从而减少或消除这些染料在水生环境中不当处理所造成的环境影响。
