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| Effects of Phosphorus at Various Concentrations on Adsorption, Uptake and Transformation of Arsenate by Spirulina platensis |
| Received:December 23, 2014 |
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| KeyWord:Spirulina platensis;phosphorus;arsenic;adsorption;absorption;transformation |
| Author Name | Affiliation | E-mail | | WANG Shu | College of Resource and Environmental Science, Nanjing Agricultural University, Nanjing 210095, China | | | XU Ping-ping | College of Resource and Environmental Science, Nanjing Agricultural University, Nanjing 210095, China | | | LIU Cong | College of Resource and Environmental Science, Nanjing Agricultural University, Nanjing 210095, China | | | WANG Ya | College of Resource and Environmental Science, Nanjing Agricultural University, Nanjing 210095, China | | | ZHANG Chun-hua | Laboratory Centre of Life Science, Nanjing Agricultural University, Nanjing 210095, China | | | GE Ying | College of Resource and Environmental Science, Nanjing Agricultural University, Nanjing 210095, China | yingge711@njau.edu.cn |
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| Abstract: |
| Arsenic(As) accumulation in Spirulina platensis may reduce the quality of health products produced from this microalga. Phosphorus(P) may influence the algal uptake and biotransformation of As. Thus it would be possible to reduce the accumulation of As in algae by manipulating P concentrations in growth media. To test this, we first sat up an experiment to examine the As(Ⅴ) adsorption and absorption characteristics of S. platensis under 0~300 μg·L-1 As(Ⅴ), and then conducted another experiment to study the effects of normal and low P levels on the As(Ⅴ) uptake, adsorption and biotransformation by S. platensis at 300 μg·L-1As(Ⅴ). Algal biomass was not significantly affected by As(Ⅴ) treatments, compared with the control. However, arsenic accumulation increased with As(Ⅴ) levels in the growth media. At 150~300 μg·L-1 As(Ⅴ), S. platensis contained 1.006 to 1.569 mg·kg-1, which exceeded the national standard(GB 16740-1997) for health(functional) foods(1.0 mg·kg-1). The As absorption was reduced by increasing P concentrations. At P levels of 1/10 normal or higher, P did not change As speciation in S. platensis, whereas only 3.28% of As was transformed to As(Ⅲ) at 1/25 normal P level. When P concentration was lowered to 1/50 of normal P level, As uptake increased significantly to 1.457 mg·kg-1, of which 9.24% and 37.35% were converted to As(Ⅲ) and DMA, respectively. In conclusion, decrease in P supply promoted the uptake, reduction and methylation of As(Ⅴ), though As(Ⅴ) was still the main As species in the microalgae. The majority of As was adsorbed on the surface of algal cells, suggesting that more than 95% of As in the S. platensis could be removed by washing with phosphate buffered saline(PBS) solution. |
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