Cloning and characterization of FMN-dependent azoreductases from textile industry effluent identified through metagenomic sequencing

Azo dyes, when released untreated in the environment, cause detrimental effects on flora and fauna. Azoreductases are enzymes capable of cleaving commercially used azo dyes, sometimes in less toxic by-products which can be further degraded via synergistic microbial cometabolism. In this study, azoreductases encoded by <i>FMN1</i> and <i>FMN2</i> genes were screened from metagenome shotgun sequences generated from the samples of textile dye industries’ effluents, cloned, expressed, and evaluated for their azo dye decolorization efficacy. At pH 7 and 45°C temperature, both recombinant enzymes FMN1 and FMN2 were able to decolorize methyl red at 20 and 100 ppm concentrations, respectively. FMN2 was found to be more efficient in decolorization/degradation of methyl red than FMN1. This study offers valuable insights into the possible application of azoreductases to reduce the environmental damage caused by azo dyes, with the hope of contributing to sustainable and eco-friendly practices for the environment management. This enzymatic approach offers a promising solution for the bioremediation of textile industrial effluents. However, the study acknowledges the need for further process optimization to enhance the efficacy of these enzymes in large-scale applications. <i>Implications</i>: The study underscores the environmental hazards associated with untreated release of azo dyes into the environment and emphasizes the potential of azoreductases, specifically those encoded by <i>FMN1</i> and <i>FMN2</i> genes, to mitigate the detrimental effects. The study emphasizes the ongoing commitment to refining and advancing the enzymatic approach for the bioremediation of azo dye-containing effluents, marking a positive stride toward more sustainable industrial practices.

偶氮染料（Azo dyes）未经处理直接排放至环境中时，会对动植物群落造成有害影响。偶氮还原酶（Azoreductases）是一类可裂解商用偶氮染料的酶，其催化产物通常为毒性更低的副产物，这类副产物可通过协同微生物共代谢途径进一步降解。本研究从纺织印染工业废水样本的宏基因组鸟枪法（metagenome shotgun）测序序列中，筛选得到由<i>FMN1</i>与<i>FMN2</i>基因编码的偶氮还原酶，随后对其进行克隆、异源表达，并评估其对偶氮染料的脱色效能。在pH 7、45℃的反应条件下，重组酶FMN1与FMN2分别可在20 ppm与100 ppm浓度下实现甲基红的脱色。相较于FMN1，FMN2在甲基红脱色与降解过程中展现出更高的催化效率。本研究为偶氮还原酶在降低偶氮染料引发的环境危害方面的应用提供了重要理论参考，以期为环境治理领域的可持续、生态友好型实践贡献助力。该酶法策略为纺织工业废水的生物修复提供了极具潜力的解决方案。但本研究同时指出，仍需开展进一步的工艺优化研究，以提升这些酶在大规模应用中的催化效能。<i>研究启示</i>：本研究强调了未经处理的偶氮染料直接排放所带来的环境风险，并着重指出了由<i>FMN1</i>与<i>FMN2</i>基因编码的偶氮还原酶在缓解此类有害影响方面的应用潜力。本研究彰显了对含偶氮染料废水生物修复的酶法策略进行优化与升级的持续探索，为迈向更可持续的工业实践迈出了积极一步。