Mechanisms of ammonium assimilation by Chlorella vulgaris F1068: Isotope fractionation and proteomic approaches
2015; Elsevier BV; Volume: 190; Linguagem: Inglês
10.1016/j.biortech.2015.04.024
ISSN1873-2976
AutoresNa Liu, Feng Li, Fei Ge, Nengguo Tao, Qiongzhi Zhou, Ming Hung Wong,
Tópico(s)Wastewater Treatment and Nitrogen Removal
ResumoRemoval of ammonium (NH4+-N) by microalgae has evoked interest in wastewater treatment, however, the detailed mechanisms of ammonium assimilation remain mysterious. This study investigated the effects of NH4+-N concentration on the removal and biotransformation efficiency by Chlorella vulgaris F1068, and explored the mechanisms by 15N isotope fractionation and proteome approaches. The results showed NH4+-N was efficiently removed (84.8%) by F1068 at 10 mg L−1 of NH4+-N. The isotope enrichment factor (ε = −2.37 ± 0.08‰) of 15N isotope fractionation revealed 47.6% biotransformation at above condition, while 7.0% biotransformation at 4 mg L−1 of NH4+-N (ε = −1.63 ± 0.06‰). This was due to the different expression of glutamine synthetase, a key enzyme in ammonium assimilation, which was up-regulated 6.4-fold at proteome level and 18.0-fold at transcription level. The results will provide a better mechanistic understanding of ammonium assimilation by microalgae and this green technology is expected to reduce the burden of NH4+-N removal for municipal sewage treatment plants.
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