Metatranscriptomics reveals the molecular mechanism of large granule formation in granular anammox reactor

Journal Article (2016)
Author(s)

Samik Bagchi (King Abdullah University of Science and Technology)

Regina Lamendella (Juniata College)

Steven Strutt (University of California)

Mark M.C. van Loosdrecht (TU Delft - BT/Environmental Biotechnology)

Pascal Saikaly (King Abdullah University of Science and Technology)

Research Group
BT/Environmental Biotechnology
Copyright
© 2016 Samik Bagchi, Regina Lamendella, Steven Strutt, Mark C.M. van Loosdrecht, Pascal E. Saikaly
DOI related publication
https://doi.org/10.1038/srep28327
More Info
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Publication Year
2016
Language
English
Copyright
© 2016 Samik Bagchi, Regina Lamendella, Steven Strutt, Mark C.M. van Loosdrecht, Pascal E. Saikaly
Research Group
BT/Environmental Biotechnology
Volume number
6
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Abstract

Granules enriched with anammox bacteria are essential in enhancing the treatment of ammonia-rich wastewater, but little is known about how anammox bacteria grow and multiply inside granules. Here, we combined metatranscriptomics, quantitative PCR and 16S rRNA gene sequencing to study the changes in community composition, metabolic gene content and gene expression in a granular anammox reactor with the objective of understanding the molecular mechanism of anammox growth and multiplication that led to formation of large granules. Size distribution analysis revealed the spatial distribution of granules in which large granules having higher abundance of anammox bacteria (genus Brocadia) dominated the bottom biomass. Metatranscriptomics analysis detected all the essential transcripts for anammox metabolism. During the later stage of reactor operation, higher expression of ammonia and nitrite transport proteins and key metabolic enzymes mainly in the bottom large granules facilitated anammox bacteria activity. The high activity resulted in higher growth and multiplication of anammox bacteria and expanded the size of the granules. This conceptual model for large granule formation proposed here may assist in the future design of anammox processes for mainstream wastewater treatment.