The effect of biotic and abiotic environmental factors on Pd(II) adsorption and reduction by Bacillus megaterium Y-4

Yuan Chen; Keqiang Hu; Yuancai Chen

doi:10.1016/j.chemosphere.2019.01.011

The effect of biotic and abiotic environmental factors on Pd(II) adsorption and reduction by Bacillus megaterium Y-4

Chemosphere. 2019 Apr:220:1058-1066. doi: 10.1016/j.chemosphere.2019.01.011. Epub 2019 Jan 4.

Authors

Yuan Chen¹, Keqiang Hu², Yuancai Chen³

Affiliations

¹ Ministry of Education Key Laboratory of Pollution Control and Ecological Remediation for Industrial Agglomeration Area, School of Environment and Energy, South China University of Technology, Guangzhou, 510006, Guangdong, PR China. Electronic address: 740441104@qq.com.
² Ministry of Education Key Laboratory of Pollution Control and Ecological Remediation for Industrial Agglomeration Area, School of Environment and Energy, South China University of Technology, Guangzhou, 510006, Guangdong, PR China.
³ Ministry of Education Key Laboratory of Pollution Control and Ecological Remediation for Industrial Agglomeration Area, School of Environment and Energy, South China University of Technology, Guangzhou, 510006, Guangdong, PR China. Electronic address: chenyc@scut.edu.cn.

PMID: 33395792
DOI: 10.1016/j.chemosphere.2019.01.011

Abstract

In this study, we screened a new aerobic bacterium (Bacillus megaterium Y-4) that can efficiently reduce Pd(II) with different electron donors. The best electron donor was sodium formate and the best reduction of Pd(II) were by log growth phase cells. The high removal capacity of Pd(II) (1658.3 mg/g) was obtained with 30 mg/L dry cell weight and 50 mg/L Pd (II) in the presence of 5 mM sodium formate. The removal amount of Pd(II) increased with initial Pd(II) concentrations ranging from 50 to 200 mg/L with 100 mg/L Pd(II) being completely removed by 148 mg/L dry cell weight in 6 h. The cell wall, periplasmic space and intracellular contents of B. megaterium Y-4 contains different kinds of enzymes for reducing Pd(II). In addition, the activity of extracellular and periplasmic enzymes was more sensitive to temperature than intracellular enzymes. XRD and XPS analysis revealed that the enzyme for reducing Pd(II) in B. megaterium Y-4 can tolerate a broad range of temperatures (20-60 °C) and pH (2.0-7.0) but was sensitive to oxygen. TEM analysis showed that biogenic palladium nanoparticles (Pd-NPs) were mainly distributed evenly in the periplasmic space of the live cells and were released from cells into aqueous solution, which reduced the toxicity of Pd(II), allowing Pd-NP recovery without cell destruction. B. megaterium Y-4 is a potential bacterium for efficient treatment and reclamation of Pd(II) pollution and formation of Pd-NPs.

Keywords: Adsorption; Bacillus megaterium Y-4; Enzymes; Palladium; Reduction.