Elnabi Manar K Abd, Ghazy Mohamed A, Ali Sameh S, Eltarahony Marwa, Nassrallah Amr
Biotechnology Program, Basic and Applied Science Institute, Egypt-Japan University of Science and Technology (E-JUST), New Borg El-Arab City, Alexandria, 21934, Egypt.
Botany and Microbiology Department, Faculty of Science, Tanta University, Tanta, 31527, Egypt.
Microb Cell Fact. 2025 Jul 2;24(1):154. doi: 10.1186/s12934-025-02768-z.
The release of azo dyes into wastewater from textile industries poses a significant environmental challenge due to their toxicity and recalcitrance. Among these dyes, Reactive Black 5 (RB5) is one of the most widely used and environmentally persistent due to its complex aromatic structure, high stability, and extensive use in the textile sector. This study aimed to develop and optimize a highly efficient bacterial consortium for the decolorization and detoxification of RB5. Three bacterial species-Bacillus cereus, Proteus mirabilis, and Stenotrophomonas maltophilia-were isolated from industrial effluents and combined into a consortium based on compatibility testing. The optimization of cultural and incubation conditions using Plackett-Burman Design (PBD) and Central Composite Design (CCD) significantly enhanced RB5 decolorization efficiency, reaching 98.56% under static conditions. Enzymatic analysis revealed the crucial role of NADH-DCIP reductase and azoreductase in azo bond cleavage, while oxidative enzymes facilitated further degradation into non-toxic metabolites. Metabolite characterization using UV-Vis, FTIR, and GC-MS confirmed the breakdown of RB5 into intermediate compounds with reduced toxicity. Toxicity assessments demonstrated a 66.38-21.38% reduction in root growth inhibition, an increase in germination rate from 40 to 93.33%, a decrease in Artemia salina mortality from 86.7 to 23.3%, and a reduction in cytotoxicity from 55.31 to 14.45% in human breast epithelial cells. These findings demonstrate the potential of the developed consortium as an eco-friendly, cost-effective solution for RB5-contaminated wastewater. Future studies should focus on pilot-scale implementation, long-term stability under variable effluent conditions, and regulatory compliance for industrial deployment.
纺织工业将偶氮染料排放到废水中，由于其毒性和难降解性，对环境构成了重大挑战。在这些染料中，活性黑5（RB5）因其复杂的芳香结构、高稳定性以及在纺织行业的广泛使用，成为使用最广泛且在环境中持久存在的染料之一。本研究旨在开发并优化一种高效的细菌联合体，用于RB5的脱色和解毒。从工业废水中分离出三种细菌——蜡样芽孢杆菌、奇异变形杆菌和嗜麦芽窄食单胞菌，并根据相容性测试将它们组合成一个联合体。使用Plackett-Burman设计（PBD）和中心复合设计（CCD）对培养和孵育条件进行优化，显著提高了RB5的脱色效率，在静态条件下达到了98.56%。酶分析表明，NADH-DCIP还原酶和偶氮还原酶在偶氮键断裂中起关键作用，而氧化酶促进了其进一步降解为无毒代谢物。使用紫外可见光谱、傅里叶变换红外光谱和气相色谱-质谱联用对代谢物进行表征，证实了RB5分解为毒性降低的中间化合物。毒性评估表明，对根生长的抑制降低了66.38 - 21.38%，发芽率从40%提高到93.33%，卤虫死亡率从86.7%降低到23.3%，人乳腺上皮细胞的细胞毒性从55.31%降低到14.45%。这些发现表明，所开发的联合体具有作为一种生态友好、经济高效的解决方案来处理受RB5污染废水的潜力。未来的研究应集中在中试规模实施、可变废水条件下的长期稳定性以及工业应用的法规合规性方面。
