Effects of Pb(II) and Cr(VI) Stress on Phosphate-Solubilizing Bacteria ( Bacillus sp. Strain MRP-3): Oxidative Stress and Bioaccumulation Potential

Wen Shao, Min Li, Zedong Teng, Bin Qiu, Yaoqiang Huo and Keyao Zhang
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Wen Shao: College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China
Min Li: College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China
Zedong Teng: College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China
Bin Qiu: College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China
Yaoqiang Huo: College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China
Keyao Zhang: College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China

IJERPH, 2019, vol. 16, issue 12, 1-14

Abstract: The aim of this work was to ascertain the effects of Pb(II) and Cr(VI) on bacterial growth, generation of reactive oxygen species (ROS), activities of superoxide dismutase (SOD), and catalase (CAT), as well as the localization of bioaccumulated heavy metals in a phosphate-solubilizing bacterium. The results showed that the ROS increased from 1.4-fold to 1.8-fold of control under Pb(II) stress and decreased from 1.6-fold to 1.1-fold of control under Cr(VI) stress corresponding to metal concentrations (0.5–5 mmol·L −1 ). The SOD activities were ROS dependent; however, the CAT activities increased under both Pb(II) and Cr(VI) stress, from 11.4 to 21.8 U·mg −1 and 11.4 to 32.9 U·mg −1 , respectively. Intra/extracellular accumulation were investigated by scanning transmission electron microscopy with energy dispersive X-ray spectroscopy (STEM-EDS) and it was calculated that extracellular accumulated Pb accounted for 61.7–95.9% of the total accumulation, while extracellular accumulated Cr only accounted for up to 3.6% of the total accumulation. Attenuated total reflection/Fourier-transform infrared spectroscopy (ATR-FTIR) analysis confirmed that the functional groups involved in those extracellular accumulation were not located in the loosely bound extracellular polysaccharides substances.

Keywords: phosphate-solubilizing bacteria; heavy metal tolerance; reactive oxygen species (ROS); antioxidative enzymes; bioaccumulation (search for similar items in EconPapers)
JEL-codes: I I1 I3 Q Q5 (search for similar items in EconPapers)
Date: 2019
References: View complete reference list from CitEc
Citations: View citations in EconPapers (1)

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