Department of Biological Sciences, Landmark University, PMB 1001, Omu Aran, Kwara State, Nigeria.
World J Microbiol Biotechnol. 2017 Dec 29;34(1):18. doi: 10.1007/s11274-017-2402-7.
The aim of this study was to assess the effect of sodium nitrate concentration on the decolouration of laboratory dyes (bromothymol blue, crystal violet, eosin blue, eosin yellow and methylene blue), by alginate immobilized cells of Pseudomonas aeruginosa and Bacillus subtilis. The sodium nitrate concentrations used in the study were 5, 10, 15 and 20 g/L. A control setup that contained no sodium nitrate was also studied. During incubation, aliquot samples were withdrawn from each flask every 24 for 144 h duration for the estimation of decolouration rate of the dyes, using standard procedures. The results revealed remarkable decolouration of the bromothymol blue and crystal violet in presence of the P. aeruginosa occurring at sodium nitrate concentrations of 10 and 15 g/L, respectively. In the case of media that was inoculated with the B. subtilis cells, although no remarkable decolouration of the bromothymol blue and crystal violet was observed throughout the period of incubation, highest decolouration were observed at sodium nitrate concentration of 5 and 10 g/L, respectively. For the eosin blue and methylene dyes, no remarkable decolouration were observed in presence of the test bacterial species at the respective sodium nitrate concentrations. Highest decolouration of the eosin yellow was however observed in media with sodium nitrate concentration of 5 g/L. The results of this study could be applied in scale up studies and continuous process, for implementation in biological decolouration of dye effluents.
本研究旨在评估硝酸钠浓度对固定化假单胞菌和枯草芽孢杆菌细胞对实验室染料（溴甲酚绿、结晶紫、伊红蓝、伊红黄和亚甲基蓝）脱色的影响。研究中使用的硝酸钠浓度分别为 5、10、15 和 20 g/L。还研究了一个不含硝酸钠的对照装置。在孵育过程中，每隔 24 小时从每个烧瓶中取出等分样品，持续 144 小时，使用标准程序估计染料的脱色率。结果表明，在 10 和 15 g/L 的硝酸钠浓度下，分别观察到假单胞菌存在时溴甲酚绿和结晶紫的显著脱色。在接种枯草芽孢杆菌细胞的培养基中，尽管在整个孵育期间都没有观察到溴甲酚绿和结晶紫的显著脱色，但在 5 和 10 g/L 的硝酸钠浓度下观察到最高的脱色。对于伊红蓝和亚甲基染料，在相应的硝酸钠浓度下，测试细菌物种存在时没有观察到显著的脱色。然而，在 5 g/L 的硝酸钠浓度下，伊红黄的脱色率最高。本研究的结果可应用于放大研究和连续过程，以实施染料废水的生物脱色。
