Direct Black G (DBG) is a highly toxic synthetic azo dye which is difficult to degrade. Biological treatment seems to be a promising option for the treatment of azo dye containing effluent. A thermophilic bacterial strain (Anoxybacillus sp. PDR2) previously isolated from the soil can effectively remove DBG. However, the molecular underpinnings of DBG degradation and the microbial detoxification ability remains unknown. In the present study, the genetic background of PDR2 for the efficient degradation of DBG and its adaptation to azo dye-contaminated environments was revealed by bioinformatics. Moreover, the possible biodegradation pathways were speculated based on the UV–vis spectral analysis, FTIR, and intermediates identified by LC-MS. Additionally, phytotoxicity and the comet experiment studies clearly indicated that PDR2 converts toxic azo dye (DBG) into low toxicity metabolites. The combination of biodegradation pathways and detoxification analysis were utilized to explore the molecular degradation mechanism and bioremediation of azo dye for future applications. These findings will provide a valuable theoretical basis for the practical treatment of azo dye wastewater.

直接黑G（DBG）是一种高毒性的合成偶氮染料，很难降解。生物处理似乎是处理含偶氮染料的废水的有前途的选择。嗜热细菌菌株（Anoxybacillussp。先前从土壤中分离出来的PDR2）可以有效去除DBG。然而，DBG降解的分子基础和微生物的解毒能力仍然未知。在当前的研究中，生物信息学揭示了PDR2有效降解DBG的遗传背景及其对偶氮染料污染环境的适应性。此外，根据紫外可见光谱分析，FTIR和LC-MS鉴定的中间体推测了可能的生物降解途径。此外，植物毒性和彗星实验研究清楚地表明，PDR2将有毒的偶氮染料（DBG）转化为低毒的代谢产物。利用生物降解途径与解毒分析相结合的方法，探索了偶氮染料的分子降解机理和生物修复方法，以备将来应用。