Moharrery Leila, Ardestani Nedasadat Saadati, Otadi Maryam
Department of Chemical Engineering, Pa.C., Islamic Azad University, Tehran, Iran.
Nanotechnology Research Center, Research Institute of Petroleum Industry (RIPI), P.O. Box: 14857-336, Tehran, Iran.
Sci Rep. 2025 Sep 26;15(1):33249. doi: 10.1038/s41598-025-18658-8.
Synthetic dye wastewater is a significant environmental concern, particularly due to its extensive usage in industries such as textiles, printing, and dyeing. Traditional methods for treating wastewater with synthetic dyes are often seen as costly and inefficient, primarily because of the dyes' robust chemical nature. In light of these challenges, there has been a growing interest in recent years in the use of biodegradation. This method utilizes specific microorganisms capable of breaking down these stubborn pollutants, offering a more sustainable and effective solution for their removal. Given the limited detailed studies on the bacterial decolorization of oil-soluble (solvent-soluble) azo dyes, there is a significant need to address this issue. The ability of salt-tolerant bacteria named Halomonas strain A3 to decolorize an oil soluble azo dye, Toluidine Red was investigated. Decolorization conditions, including initial dye concentration, pH, NaCl percent (w/v), and incubation temperature, were optimized using the one-factor-at-a-time method with dye as the sole carbon and energy source. The ultraviolet-visible spectrophotometric method, high-performance liquid chromatography, and gas chromatography mass spectrometry analyses were used to investigate the decolorization mechanism at optimum condition, including 25 ppm dye concentration, 5% (w/v) NaCl, pH 6.5, and incubation temperature of 35 °C. Compared to the parent dye, the ultraviolet-visible scan of the supernatant suggested that the degradation mechanism was the main reason for color removal rather than inactive surface adsorption. HPLC analysis confirmed this conclusion. The final compounds produced from TR degradation were identified as benzene diazonium (m/z 105 ± 1) and 3-Phenyl-acrylic acid (m/z 149 ± 1). According to the results, Halomonas strain A3 is a practical alternative for degrading effluents containing oil-soluble azo dyes in salty conditions. A pathway for dye degradation was predicted based on the obtained intermediate and final products.
合成染料废水是一个重大的环境问题，尤其是由于其在纺织、印染等行业的广泛使用。传统的合成染料废水处理方法通常被认为成本高且效率低，主要是因为染料具有稳定的化学性质。鉴于这些挑战，近年来人们对生物降解的应用越来越感兴趣。这种方法利用特定的微生物来分解这些顽固的污染物，为去除污染物提供了一种更可持续、更有效的解决方案。鉴于关于耐盐细菌对偶氮染料的细菌脱色的详细研究有限，因此迫切需要解决这个问题。研究了耐盐细菌嗜盐单胞菌菌株A3对偶氮染料甲苯胺红的脱色能力。以染料作为唯一碳源和能源，采用单因素法优化了脱色条件，包括初始染料浓度、pH值、NaCl质量分数（w/v）和培养温度。采用紫外可见分光光度法、高效液相色谱法和气相色谱-质谱分析法研究了在最佳条件下（染料浓度25 ppm、NaCl 5%（w/v）、pH 6.5、培养温度35℃）的脱色机理。与母体染料相比，上清液的紫外可见扫描表明，降解机理是脱色的主要原因，而不是非活性表面吸附。高效液相色谱分析证实了这一结论。甲苯胺红降解产生的最终化合物被鉴定为苯重氮（m/z 105±1）和3-苯基丙烯酸（m/z 149±1）。结果表明，嗜盐单胞菌菌株A3是在含盐条件下降解含油溶性偶氮染料废水的一种实用替代方法。根据获得的中间产物和最终产物预测了染料降解途径。
