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Genomic and Metabolic Insights into Two Novel Thiothrix Species from Enhanced Biological Phosphorus Removal Systems

Authors :
Andrey V. Mardanov
Eugeny V. Gruzdev
Dmitry D. Smolyakov
Tatyana S. Rudenko
Alexey V. Beletsky
Maria V. Gureeva
Nikita D. Markov
Yulia Yu. Berestovskaya
Nikolai V. Pimenov
Nikolai V. Ravin
Margarita Yu. Grabovich
Source :
Microorganisms, Vol 8, Iss 12, p 2030 (2020)
Publication Year :
2020
Publisher :
MDPI AG, 2020.

Abstract

Two metagenome-assembled genomes (MAGs), obtained from laboratory-scale enhanced biological phosphorus removal bioreactors, were analyzed. The values of 16S rRNA gene sequence identity, average nucleotide identity, and average amino acid identity indicated that these genomes, designated as RT and SSD2, represented two novel species within the genus Thiothrix, ‘Candidatus Thiothrix moscowensis’ and ‘Candidatus Thiothrix singaporensis’. A complete set of genes for the tricarboxylic acid cycle and electron transport chain indicates a respiratory type of metabolism. A notable feature of RT and SSD2, as well as other Thiothrix species, is the presence of a flavin adenine dinucleotide (FAD)-dependent malate:quinone oxidoreductase instead of nicotinamide adenine dinucleotide (NAD)-dependent malate dehydrogenase. Both MAGs contained genes for CO2 assimilation through the Calvin–Benson–Bassam cycle; sulfide oxidation (sqr, fccAB), sulfur oxidation (rDsr complex), direct (soeABC) and indirect (aprBA, sat) sulfite oxidation, and the branched Sox pathway (SoxAXBYZ) of thiosulfate oxidation to sulfur and sulfate. All these features indicate a chemoorganoheterotrophic, chemolithoautotrophic, and chemolithoheterotrophic lifestyle. Both MAGs comprise genes for nitrate reductase and NO-reductase, while SSD2 also contains genes for nitrite reductase. The presence of polyphosphate kinase and exopolyphosphatase suggests that RT and SSD2 could accumulate and degrade polyhosphates during the oxic-anoxic growth cycle in the bioreactors, such as typical phosphate-accumulating microorganisms.

Details

Language :
English
ISSN :
20762607
Volume :
8
Issue :
12
Database :
Directory of Open Access Journals
Journal :
Microorganisms
Publication Type :
Academic Journal
Accession number :
edsdoj.414f5bab724e04a6e706a7e4b6a6dd
Document Type :
article
Full Text :
https://doi.org/10.3390/microorganisms8122030