Lade Harshad, Kadam Avinash, Paul Diby, Govindwar Sanjay
Department of Environmental Engineering, Konkuk University, Seoul 143-701, Korea.
Department of Environmental Engineering, Kyungpook National University, Daegu 702-701, Korea.
Int J Environ Res Public Health. 2015 Mar 25;12(4):3480-505. doi: 10.3390/ijerph120403480.
Environmental release of benzidine-based dyes is a matter of health concern. Here, a microbial consortium was enriched from textile dye contaminated soils and investigated for biodegradation of the carcinogenic benzidine-based dye Trypan Blue using wheat bran (WB) as growth medium. The PCR-DGGE analysis of enriched microbial consortium revealed the presence of 15 different bacteria. Decolorization studies suggested that the microbial consortium has high metabolic activity towards Trypan Blue as complete removal of 50 mg∙L-1 dye was observed within 24 h at 30 ± 0.2 °C and pH 7. Significant reduction in TOC (64%) and COD (88%) of dye decolorized broths confirmed mineralization. Induction in azoreductase (500%), NADH-DCIP reductase (264%) and laccase (275%) proved enzymatic decolorization of dye. HPLC analysis of dye decolorized products showed the formation of six metabolites while the FTIR spectrum indicated removal of diazo bonds at 1612.30 and 1581.34 cm-1. The proposed dye degradation pathway based on GC-MS and enzyme analysis suggested the formation of two low molecular weight intermediates. Phytotoxicity and acute toxicity studies revealed the less toxic nature of the dye degradation products. These results provide experimental evidence for the utilization of agricultural waste as a novel low-cost growth medium for biodegradation of benzidine-based dyes, and suggested the potential of the microbial consortium in detoxification.
联苯胺类染料的环境释放是一个备受关注的健康问题。在此，从受纺织染料污染的土壤中富集了一个微生物群落，并以麦麸（WB）作为生长培养基，研究其对致癌性联苯胺类染料锥虫蓝的生物降解作用。对富集的微生物群落进行的PCR-DGGE分析表明存在15种不同的细菌。脱色研究表明，该微生物群落在30±0.2°C和pH 7的条件下，对锥虫蓝具有较高的代谢活性，在24小时内可完全去除50mg∙L-1的染料。染料脱色肉汤中TOC（64%）和COD（88%）的显著降低证实了矿化作用。偶氮还原酶（500%）、NADH-DCIP还原酶（264%）和漆酶（275%）的诱导证明了染料的酶促脱色。对染料脱色产物的HPLC分析显示形成了六种代谢物，而FTIR光谱表明在1612.30和1581.34 cm-1处偶氮键被去除。基于GC-MS和酶分析提出的染料降解途径表明形成了两种低分子量中间体。植物毒性和急性毒性研究表明染料降解产物的毒性较低。这些结果为利用农业废弃物作为联苯胺类染料生物降解的新型低成本生长培养基提供了实验证据，并表明了该微生物群落在解毒方面的潜力。
