Natural Resources and Environment Laboratory, Polydisciplinary Faculty of Taza, Sidi Mohamed Ben Abdellah University, Fez, Morocco.
Biotechnology, Environment, Agri-Food and Health Laboratory, Faculty of Sciences Dhar El Mahraz, Sidi Mohamed Ben Abdellah University, Fez, Morocco.
Extremophiles. 2022 Sep 23;26(3):30. doi: 10.1007/s00792-022-01278-9.
Chromium is one of the most widely used metals in industry. Hexavalent form [Cr(VI)], which is found in industrial discharges, is very toxic and very soluble in water. From soil taken from an abandoned lead and iron mine, a bacterial strain capable of reducing Cr(VI) was isolated and identified as Brachybacterium paraconglomeratum ER41. Objective of this work was to evaluate the power of this bacterium to reduce Cr(VI). Results obtained showed that this bacterium is capable of eliminating 100 mg/L of Cr(VI) after 48 h (pH 8 and temperature 30 °C). For modeling biosorption kinetics, pseudo-first-order and intraparticle diffusion models gave a better fit. Furthermore, the adsorption mechanism conformed well to Langmuir's isothermal model indicating monolayer type sorption. Biomass analysis of this bacterium before and after contact with chromium by scanning electron microscopy-energy-dispersive X-ray and by Fourier transform infrared spectroscopy showed that the surface ligands of bacterial wall are probably responsible for biosorption and bioreduction process. These results suggest a potential application of B. paraconglomeratum ER41 in bioremediation of polluted discharges.
铬是工业中应用最广泛的金属之一。六价形式[Cr(VI)]存在于工业排放物中，毒性很强，在水中溶解度很高。从废弃的铅铁矿中采集的土壤中分离出一种能够还原 Cr(VI)的细菌菌株，并鉴定为短杆菌属 ER41。本工作的目的是评估该细菌还原 Cr(VI)的能力。结果表明，该细菌在 pH 8 和温度 30°C 下 48 小时内能够消除 100mg/L 的 Cr(VI)。为了对生物吸附动力学进行建模，拟一级和内扩散模型的拟合效果更好。此外，吸附机制符合 Langmuir 等温模型，表明是单层吸附。扫描电子显微镜-能谱和傅里叶变换红外光谱分析表明，细菌细胞壁表面配体可能是生物吸附和生物还原过程的原因。这些结果表明，短杆菌属 ER41 有可能应用于受污染排放物的生物修复。
