Efficient ammonium removal through heterotrophic nitrification-aerobic denitrification by Acinetobacter baumannii strain AL-6 in the presence of Cr(VI)

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A novel strain AL-6, which was identified as Acinetobacter baumannii, presented an efficient ability to remove ammonium. Nitrogen balance indicates that 55.8% of the initial NH4+–N was ultimately converted to N2 through heterotrophic nitrification and aerobic denitrification, while 30.6% was contributed to assimilation. More interestingly, efficient ammonium removal could be achieved in the presence of Cr(VI) of 0–10 mg L−1 by strain AL-6. Meanwhile, Cr(VI) reduction was observed. The Cr(VI) was mainly reduced to less toxic Cr(III) by strain AL-6 in the culture, while a small part of Cr(VI) might be accumulated in bacterial cells in the formation of Cr(III). The optimal conditions for ammonium removal as well as Cr(VI) reduction was pH of 7 and C/N ratio of 10–15. This study provided a potential prospect for the treatment of Cr(VI)-containing ammonium wastewater.

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Media

The bacterial enrichment medium (EM) consisted of following components (per liter): 10 g peptone, 10 g beef extract, 5 g NaCl, 4.78 g Na2HPO4·12H2O, 1.24 g NaH2PO4·2H2O.

The basal medium (BM) used for bacterial isolation and NH4+–N removal experiments contained (per liter): 0.30 g NH4Cl, 2.73 g CH3COONa, 0.75 g K2HPO4·3H2O, 0.28 g KH2PO4, 1.00 g NaCl and 3.0 mL trace element solution. The agar plates were prepared by adding 20 g agar per liter to BM.

The Cr(VI)-containing medium (CM) for Cr(VI)

Identification of strain AL-6

By repeated streaking on fresh agar plates, six isolates were purified, and their nitrogen removal capabilities were tested individually. Strain AL-6 with the highest growth rate and nitrogen removal in the presence of Cr(VI) was selected for the following trials. The mature colony of strain AL-6 was translucent, smooth and round, with a pale pink under natural light. The partial 16S rRNA gene sequence of strain AL-6 was obtained and deposited in GenBank with the accession number KY930369. The

Acknowledgments

This work was supported by the technology innovation and application demonstration project of Chongqing CSTC (Project No. xstc2018jscx-msybX0308).

References (44)

  • Q.L. Zhang et al.

    The characteristics of a novel heterotrophic nitrification-aerobic denitrification bacterium, Bacillus methylotrophicus strain L7

    Bioresour. Technol.

    (2012)
  • F. Fu et al.

    Removal of heavy metal ions from wastewaters: a review

    J. Environ. Manag.

    (2011)
  • U. Duran et al.

    Two combined mechanisms responsible to hexavalent chromium removal on active anaerobic granular consortium

    Chemosphere

    (2018)
  • D. He et al.

    Interaction of Cr(VI) reduction and denitrification by strain Pseudomonas aeruginosa PCN-2 under aerobic conditions

    Bioresour. Technol.

    (2015)
  • Y. Yu et al.

    Highly synergistic effects on ammonium removal by the co-system of Pseudomonas stutzeri XL-2 and modified walnut shell biochar

    Bioresour. Technol.

    (2019)
  • S. Sharma et al.

    Bioremediation of tannery wastewater by chromium resistant novel fungal consortium

    Ecol. Eng.

    (2016)
  • D. Park et al.

    XAS and XPS studies on chromium-binding groups of biomaterial during Cr(VI) biosorption

    J. Colloid Interf. Sci.

    (2008)
  • B. Zhao et al.

    Characterization of an aerobic denitrifier Pseudomonas stutzeri strain XL-2 to achieve efficient nitrate removal

    Bioresour. Technol.

    (2018)
  • S. Zhang et al.

    Heterotrophic nitrification and aerobic denitrification by Diaphorobacter polyhydroxybutyrativorans SL-205 using poly(3-hydroxybutyrate-co-3-hydroxyvalerate) as the sole carbon source

    Bioresour. Technol.

    (2017)
  • J.R. Yang et al.

    Ammonium removal characteristics of an acid-resistant bacterium Acinetobacter sp. JR1 from pharmaceutical wastewater capable of heterotrophic nitrification-aerobic denitrification

    Bioresour. Technol.

    (2019)
  • S. Yao et al.

    Heterotrophic nitrification and aerobic denitrification at low temperature by a newly isolated bacterium, Acinetobacter sp. HA2

    Bioresour. Technol.

    (2013)
  • T. Wang et al.

    Heterotrophic nitrogen removal by a newly-isolated alkalitolerant microorganism, Serratia marcescens W5

    Bioresour. Technol.

    (2016)

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