Departamento de Ingeniería Bioquímica, Escuela Nacional de Ciencias Biológicas, IPN, Carpio y Plan de Ayala, Col. Santo Tomás, México, D.F., Mexico.
Appl Biochem Biotechnol. 2010 Nov;162(6):1689-707. doi: 10.1007/s12010-010-8950-z. Epub 2010 Apr 8.
A microbial community able to aerobically degrade the azo dye Acid Orange 7 was selected from riparian or lacustrine sediments collected at sites receiving textile wastewaters. Three bacterial strains, pertaining to the genera Pseudomonas, Arthrobacter, and Rhizobium, constitute the selected community. The biodegradation of AO7 was carried out in batch-suspended cell culture and in a continuously operated multistage packed-bed BAC reactor. The rapid decolorization observed in batch culture, joined to a delay of about 24 h in COD removal and cell growth, suggests that enzymes involved in biodegradation of the aromatic amines generated after AO7 azo-bond cleavage (1-amino-2-naphthol [1-A2N] and 4-aminobenzenesulfonic acid [4-ABS]), are inducible in this microbial consortium. After this presumptive induction period, the accumulated byproducts, measured through COD, were partially metabolized and transformed in cell mass. At all azo dye loading rates used, complete removal of AO7 and 1-A2N was obtained in the multistage packed-bed BAC reactor (PBR).; however, the overall COD (eta ( COD )) and 4-ABS (eta ( ABS )) removal efficiencies obtained in steady state continuous culture were about 90%. Considering the toxicity of 1-A2N, its complete removal has particular relevance. In the first stages of the packed-bed BAC reactor (Fig. 4a-c), major removal was observed. In the last stage, only a slight removal of COD and 4-ABS was obtained. Comparing to several reported studies, the continuously operated multistage packed-bed BAC reactor showed similar or superior results. In addition, the operation of large-packed-bed BAC reactors could be improved by using several shallow BAC bed stages, because the pressure drop caused by bed compaction of a support material constituted by small and fragile particles can be reduced.
从接收纺织废水的河岸或湖泊沉积物中选择了能够好氧降解偶氮染料酸性橙 7 的微生物群落。三个细菌菌株，属于假单胞菌、节杆菌和根瘤菌属，构成了所选的群落。AO7 的生物降解在分批悬浮细胞培养和连续操作的多级填充床 BAC 反应器中进行。在分批培养中观察到的快速脱色，加上 COD 去除和细胞生长延迟约 24 小时，表明在 AO7 偶氮键断裂后（1-氨基-2-萘酚[1-A2N]和 4-氨基苯磺酸[4-ABS]）生成的芳香胺的生物降解酶在该微生物共混物中是可诱导的。在这个假定的诱导期之后，通过 COD 测量积累的副产物部分代谢并转化为细胞物质。在使用的所有偶氮染料加载速率下，多级填充床 BAC 反应器（PBR）都能完全去除 AO7 和 1-A2N；然而，在稳态连续培养中获得的总 COD（eta（COD））和 4-ABS（eta（ABS））去除效率约为 90%。考虑到 1-A2N 的毒性，其完全去除具有特殊意义。在填充床 BAC 反应器的最初几个阶段（图 4a-c）中观察到主要去除。在最后一个阶段，仅获得 COD 和 4-ABS 的轻微去除。与几项已报道的研究相比，连续操作的多级填充床 BAC 反应器显示出相似或更好的结果。此外，通过使用几个浅层 BAC 床阶段，可以改善大型填充床 BAC 反应器的运行，因为由小而脆弱的颗粒组成的支撑材料的床压实引起的压降可以降低。
