Biomolecules Lab, School of Biosciences and Technology, Vellore Institute of Technology, Vellore, India.
Water Environ Res. 2020 Aug;92(8):1230-1241. doi: 10.1002/wer.1319. Epub 2020 Apr 26.
Reactive dyes are pernicious pollutants in textile effluent, which are to be treated passably before discharging into the environment. In the present study, a potential dye degrading bacterial strain Pseudomonas guariconensis was isolated from paddy rhizosphere and was characterized by 16S rRNA gene sequencing. The biodegradation ability of the strain was evaluated by time-based study with immobilized bacterial cells in calcium alginate biocarrier matrix and also with free cells. The results indicated that the strain exhibited maximum degradation of 91% when immobilized in the biocarrier matrix. The enzymatic study revealed the production of oxidoreductase enzymes. The degraded products were identified as 2-amino-3-phenylpropanoic acid and benzoquinone by gas chromatography-mass spectroscopy (GC-MS) analysis, and a degradative pathway was derived based on the enzymatic profile. A packed bed column was designed using P. guariconensis VITSAJ5 immobilized in calcium alginate beads as a biosorbent for the removal of Reactive Red 120. The immobilized bacterial cells exhibited 87% uptake of RR120, whereas the nonimmobilized bacterial cells exhibited a maximum uptake of 37%. The phytotoxicity analysis by seed germination assay revealed an enhanced plumule and radicle length, indicating the nontoxic byproducts after the treatment of Reactive Red 120 by VITSAJ5 compared to the untreated Reactive Red 120 solution. PRACTITIONER POINTS: Current study is the first report on Pseudomonas guariconensis capable of degrading reactive dyes (Reactive Red 120) It was observed that the degradation potential was maximum when cells were immobilized with Ca-Ag biocarrier matrix Breakdown metabolism of Reactive Red 120 was derived through pathway prediction Employing immobilized bacteria in a packed bed column found to possess a prominent biosorption ability on the matrix enhancing the degradation process Toxic reactive dye was converted into nontoxic compounds, evidenced by phytotoxicity studies.
反应性染料是纺织废水中的有害污染物，在排放到环境中之前需要进行适当处理。本研究从稻田根际中分离出一株潜在的染料降解细菌假单胞菌，并通过 16S rRNA 基因测序进行了鉴定。通过在海藻酸钙生物载体基质中固定化细菌细胞和游离细胞的时间研究评估了该菌株的生物降解能力。结果表明，当固定在生物载体基质中时，该菌株的最大降解率为 91%。酶学研究表明，该菌株产生了氧化还原酶。通过气相色谱-质谱（GC-MS）分析，鉴定降解产物为 2-氨基-3-苯丙酸和苯醌，并根据酶谱推导了降解途径。使用固定在海藻酸钙珠中的 P. guariconensis VITSAJ5 设计了填充床柱，作为去除活性红 120 的生物吸附剂。固定化细菌细胞对 RR120 的摄取率为 87%，而非固定化细菌细胞的最大摄取率为 37%。种子发芽试验的植物毒性分析表明，处理活性红 120 后的幼苗和根长增加，表明与未经处理的活性红 120 溶液相比，VITSAJ5 处理后的副产物无毒。
当前的研究是首次报道假单胞菌能够降解活性染料（活性红 120）。
观察到当细胞用 Ca-Ag 生物载体基质固定化时，降解潜力最大。
通过途径预测得出了活性红 120 的分解代谢。
在填充床柱中使用固定化细菌发现对基质具有突出的生物吸附能力，增强了降解过程。
有毒的活性染料被转化为无毒的化合物，这一点可以通过植物毒性研究得到证明。
