Abstract The decolorization of toxic azo dye Ponceau 4R by three strains of bacteria Bacillus sp. strain AK1, Lysinibacillus sp. strain AK2 and Kerstersia sp. strain VKY1 individually and in consortia was studied. At optimal conditions, up to 95%, 93% and 87% of the dye was decolorized by the strains AK1, AK2 and VKY1, respectively, in 24 h at 200 mg/L of the dye. Decolorization of the dye was optimized for different parameters such as the concentration of dye, pH, temperature and NaCl concentration. These strains were able to decolorize Ponceau 4R up to an initial concentration of 800 mg/L in the pH range of 5–10, temperature 25–55 °C and NaCl concentration up to 30 g/L. The dye decolorization efficiency of these strains was further enhanced by using different consortia of AK1, AK2 and VKY1 in various combinations. The complete decolorization of the dye by a consortium was achieved within 18 h at 200 mg/L. The cell-free extract of these strains grown on this dye exhibited a remarkable activity of azoreductase which is involved in the breakage of the azo bond. The steady-state kinetics of azoreductase, validated the ping pong Bi-Bi mechanism of enzyme action. UV–Vis spectra, HPLC, FTIR and LC-MS analysis of the dye decolorized samples showed the formation of 4-aminonaphthalene-1-sulphonic acid and 5-amino-6-hydroxynaphthalene-2, 4-disulphonic acid as the products of azo bond breakage. The phytotoxicity test of decolorized sample revealed a considerable reduction in the toxicity in comparison with the parent dye.

中文翻译：

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单菌群和混合菌群对磺化偶氮染料丽春红4R的高效脱色解毒

摘要 三株芽孢杆菌对有毒偶氮染料丽春红4R的脱色作用。菌株 AK1，赖氨酸杆菌属。菌株 AK2 和 Kerstersia sp。单独和联合研究了菌株 VKY1。在最佳条件下，菌株 AK1、AK2 和 VKY1 在 24 小时内以 200 毫克/升的染料分别使高达 95%、93% 和 87% 的染料脱色。针对染料浓度、pH、温度和NaCl浓度等不同参数优化染料的脱色。这些菌株能够在 5-10 的 pH 值范围、25-55°C 的温度和高达 30 g/L 的 NaCl 浓度下将 Ponceau 4R 脱色至初始浓度为 800 mg/L。通过以各种组合使用不同的 AK1、AK2 和 VKY1 菌群，这些菌株的染料脱色效率进一步提高。联合体在 18 小时内实现了染料的完全脱色，浓度为 200 mg/L。在这种染料上生长的这些菌株的无细胞提取物表现出显着的偶氮还原酶活性，该酶参与偶氮键的断裂。偶氮还原酶的稳态动力学验证了酶作用的乒乓Bi-Bi机制。染料脱色样品的 UV-Vis 光谱、HPLC、FTIR 和 LC-MS 分析表明形成 4-aminonaphthalene-1-sulphonic acid 和 5-amino-6-hydroxynaphthalene-2, 4-disulphonic acid 作为偶氮的产物债券断裂。脱色样品的植物毒性试验表明，与母体染料相比，其毒性显着降低。在这种染料上生长的这些菌株的无细胞提取物表现出显着的偶氮还原酶活性，该酶参与偶氮键的断裂。偶氮还原酶的稳态动力学验证了酶作用的乒乓Bi-Bi机制。染料脱色样品的 UV-Vis 光谱、HPLC、FTIR 和 LC-MS 分析表明形成了 4-aminonaphthalene-1-sulphonic acid 和 5-amino-6-hydroxynaphthalene-2, 4-disulphonic acid 作为偶氮的产物债券断裂。脱色样品的植物毒性试验表明，与母体染料相比，其毒性显着降低。在这种染料上生长的这些菌株的无细胞提取物表现出显着的偶氮还原酶活性，该酶参与偶氮键的断裂。偶氮还原酶的稳态动力学验证了酶作用的乒乓Bi-Bi机制。染料脱色样品的 UV-Vis 光谱、HPLC、FTIR 和 LC-MS 分析表明形成 4-aminonaphthalene-1-sulphonic acid 和 5-amino-6-hydroxynaphthalene-2, 4-disulphonic acid 作为偶氮的产物债券断裂。脱色样品的植物毒性试验表明，与母体染料相比，其毒性显着降低。染料脱色样品的 FTIR 和 LC-MS 分析表明，形成了 4-氨基萘-1-磺酸和 5-氨基-6-羟基萘-2, 4-二磺酸作为偶氮键断裂的产物。脱色样品的植物毒性试验表明，与母体染料相比，其毒性显着降低。染料脱色样品的 FTIR 和 LC-MS 分析表明，形成了 4-氨基萘-1-磺酸和 5-氨基-6-羟基萘-2, 4-二磺酸作为偶氮键断裂的产物。脱色样品的植物毒性试验表明，与母体染料相比，其毒性显着降低。