Abstract：
Bacillus nitratireducens was isolated from textile effluent and showed high tolerance to chromium (Cr), reaching up to a 1000 mg/L MIC value. This research was aimed at utilizing biosorbents from live and dead cells of B. nitratireducens to remove Cr from an aqueous solution. A batch biosorption test was performed, and mechanisms analysis was approached by an adsorption-desorption test, SEM-EDS, and FTIR analysis. Cr removal by dead cells in 25, 50, and 100 mg/L of Cr were 58.99 ± 0.7%, 69.8 ± 0.2%, and 82.87 ± 0.11%, respectively, while that by live cells was 73.08 ± 1.9%, 80.27 ± 6.33%, and 86.17 ± 1.93%, respectively. Live cells showed significantly higher Cr removal and adsorption capacities as compared to dead cells. In all concentrations, absorption contributed more than adsorption to the Cr removal by both live and dead cells. Absorption of Cr was subjected to occur due to passive mechanisms in dead cells while involving some active mechanisms in live cells. SEM-EDS confirmed the detection of Cr on the cell surface, while FTIR revealed the shifting of some peaks after the biosorption test, suggesting interactions between Cr and functional groups. Further TEM analysis is suggested to be conducted as a future approach to reveal the inner structure of cells and confirm the involvement of absorption mechanisms.
摘要：
从纺织废水中分离出硝化还原芽孢杆菌，对铬（Cr）具有较高的耐受性，达到1000mg/L的MIC值。这项研究旨在利用硝化还原芽孢杆菌的活细胞和死细胞中的生物吸附剂从水溶液中去除Cr。进行了分批生物吸附测试，并通过吸附-解吸试验进行了机理分析，SEM-EDS,和FTIR分析。在25、50和100mg/L的Cr中，死细胞的Cr去除率为58.99±0.7％，69.8±0.2%,和82.87±0.11%，分别,而活细胞的比例为73.08±1.9%，80.27±6.33%,和86.17±1.93%，分别。与死细胞相比，活细胞显示出明显更高的Cr去除和吸附能力。在所有浓度中，吸收对活细胞和死细胞去除Cr的贡献大于吸附。Cr的吸收是由于死细胞中的被动机制而发生的，而在活细胞中涉及一些主动机制。SEM-EDS证实了细胞表面Cr的检测，而FTIR显示了生物吸附试验后一些峰的移动，表明Cr和官能团之间的相互作用。建议进行进一步的TEM分析，以揭示细胞的内部结构并确认吸收机制的参与。
