There has been an interest in the microbial azo dye degradation as an optional method for the treatment of azo dye-containing wastes. Tattoo ink is an extremely unique azo dye-rich environment, which have never been explored in terms of microorganisms capable of degrading azo dyes. Previously, we isolated 81 phylogenetically diverse bacteria, belonging to 18 genera and 52 species, contaminated in tattoo inks. In this study, we investigated if these bacteria, which can survive in the azo dye-rich environment, have an ability to degrade azo dyes. We conducted a two-step azo dye degradation (or decolorization) assay. In step 1, a high-throughput degradability assay was done for 79 bacterial isolates using Methyl Red and Orange II. In step 2, a further degradation assay was done for 10 selected bacteria with a representative of 11 azo dyes, including 3 commercial tattoo ink azo dyes. Degradation of azo dyes were calculated from measuring optical absorbance of soluble dyes at specific wavelengths. The initial high-throughput azo dye assay (step 1) showed that 79 isolates had a complete or partial degradation of azo dyes; > 90% of Methyl Red and Orange II were degraded within 24 h, by 74 and 20 isolates, respectively. A further evaluation of azo dye degradability for 10 selected isolates in step 2 showed that the isolates, belonging to Bacillus, Brevibacillus, Paenibacillus, and Pseudomonas, exhibited an excellent decolorization ability for a wide range of azo dyes. This study showed that phylogenetically diverse bacteria, isolated from azo dye-rich tattoo inks, is able to degrade a diverse range of azo dyes, including 3 azo dyes used in commercial tattoo inks. Some of the strains would be good candidates for future studies to provide a systematic understanding of azo dye degradation mechanisms.

中文翻译：

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从纹身墨水中分离出的系统发育多样的细菌，一种富含偶氮染料的环境，可以使多种偶氮染料脱色

微生物偶氮染料降解作为处理含偶氮染料废物的可选方法引起了人们的兴趣。纹身墨水是一种极其独特的富含偶氮染料的环境，在能够降解偶氮染料的微生物方面从未被探索过。此前，我们分离出被纹身墨水污染的 81 种系统发育不同的细菌，属于 18 属 52 种。在这项研究中，我们调查了这些可以在富含偶氮染料的环境中生存的细菌是否具有降解偶氮染料的能力。我们进行了两步偶氮染料降解（或脱色）测定。在步骤 1 中，使用甲基红和橙 II 对 79 种细菌分离物进行了高通量降解性测定。在步骤 2 中，用 11 种偶氮染料对 10 种选定的细菌进行了进一步的降解测定，包括 3 种商业纹身墨水偶氮染料。通过测量可溶性染料在特定波长的吸光度来计算偶氮染料的降解。最初的高通量偶氮染料测定（步骤 1）表明，79 株分离物完全或部分降解了偶氮染料；> 90% 的甲基红和橙 II 在 24 小时内分别被 74 和 20 个分离物降解。在步骤 2 中对 10 个选定分离物的偶氮染料降解能力的进一步评估表明，这些分离物属于芽孢杆菌属、短芽孢杆菌属、类芽孢杆菌属和假单胞菌属，对多种偶氮染料表现出优异的脱色能力。这项研究表明，从富含偶氮染料的纹身墨水中分离出的系统发育不同的细菌能够降解多种偶氮染料，包括商业纹身墨水中使用的 3 种偶氮染料。