A novel perchlorate- and nitrate-reducing bacterium, Azospira sp. PMJ

Issue Date

7-2016

Abstract

A novel perchlorate-reducing bacterium (PCRB), PMJ, was isolated from the mixed liquor suspended solids in the aerobic tank of a wastewater treatment plant. The 16S ribosomal RNA (rRNA), perchlorate reductase, and chlorite dismutase gene sequences revealed that PMJ belonged to the genus Azospira. PMJ was removed high-strength (700 mg/L) perchlorate and also removed low-strength (≤50 mg/L) perchlorate below the detection limit (2 μg/L) when acetate was used as a sole and carbon source. The maximum specific perchlorate utilization rate, qmax, was 0.96 mg ClO4−/mg dry cell weight day, and the half-saturation constant, KS, was lower than 0.002 mg ClO4−/L. PMJ also utilized inorganic electron donors [(H2, S0, and Fe(II)] with perchlorate as an electron acceptor. Perchlorate reduction by PMJ was completely inhibited by oxygen and chlorate but was not inhibited by nitrate. In the presence of similar concentrations (100∼140 mg/L) of nitrate and perchlorate, PMJ simultaneously removed both electron acceptors. Therefore, it was concluded that the strains PMJ might possess separate pathways for perchlorate and nitrate reduction. These results indicated that Azospira sp. PMJ could be efficiently used for treating perchlorate-contaminated groundwater and wastewater because many of these water bodies are known to contain both perchlorate and nitrate. In addition, low KS value and autotrophic perchlorate reduction of PMJ might be useful to design the biological treatment systems.

Source or Periodical Title

Applied Microbiology and Biotechnology

ISSN

0175-7598

Volume

100

Issue

13

Page

6055-6068

Document Type

Article

Physical Description

illustrations, graphs

Language

English

Subject

Autotrophic perchlorate reduction, Azospira sp. PMJ, Kinetic parameters, Perchlorate-reducing bacteria (PCRB), Simultaneous perchlorate and nitrate reduction

Identifier

DOI:100. 10.1007/s00253-016-7401-3.

Digital Copy

yes

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