Flocculation-Related Gene Identification by Whole-Genome Sequencing of Thauera aminoaromatica MZ1T Floc-Defective Mutants

Thauera aminoaromatica MZ1T, a floc-forming bacterium isolated from an industrial activated-sludge wastewater treatment plant, overproduces exopolysaccharide (EPS), leading to viscous bulking. This phenomenon results in poor sludge settling and dewatering during the clarification process. To identif...

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Main Authors:	Prombutara, P., Allen, M. S.
Format:	Online
Language:	English
Published:	American Society for Microbiology 2016
Online Access:	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4784049/

id	pubmed-4784049
recordtype	oai_dc
spelling	pubmed-47840492016-04-04 Flocculation-Related Gene Identification by Whole-Genome Sequencing of Thauera aminoaromatica MZ1T Floc-Defective Mutants Prombutara, P. Allen, M. S. Environmental Microbiology Thauera aminoaromatica MZ1T, a floc-forming bacterium isolated from an industrial activated-sludge wastewater treatment plant, overproduces exopolysaccharide (EPS), leading to viscous bulking. This phenomenon results in poor sludge settling and dewatering during the clarification process. To identify genes responsible for bacterial flocculation, a whole-genome phenotypic-sequencing technique was applied. Genomic DNA of MZ1T flocculation-deficient mutants was subjected to massively parallel sequencing. The resultant high-quality reads were assembled and compared to the reference genome of the wild type (WT). We identified nine nonsynonymous mutations and one nonsense mutation putatively involved in EPS biosynthesis. Complementation of the nonsense mutation located in an EPS deacetylase gene restored the flocculating phenotype. The Fourier transform infrared (FTIR) spectra of EPS isolated from the wild type showed a reduced C=O peak of the N-acetyl group at 1,665 cm−1 compared to the spectra of MZ1T floc-deficient mutant EPS, suggesting that the WT EPS was partially deacetylated. Gene expression analysis also demonstrated that the putative deacetylase gene transcript increased before flocculation occurred. These data suggest that targeting deacetylation processes via direct chemical modification of EPS or enzyme inhibition may prove useful in combating viscous bulking in this and related bacteria. American Society for Microbiology 2016-03-07 /pmc/articles/PMC4784049/ /pubmed/26712552 http://dx.doi.org/10.1128/AEM.02917-15 Text en Copyright © 2016 Prombutara and Allen. http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International license (http://creativecommons.org/licenses/by/4.0/) .
repository_type	Open Access Journal
institution_category	Foreign Institution
institution	US National Center for Biotechnology Information
building	NCBI PubMed
collection	Online Access
language	English
format	Online
author	Prombutara, P. Allen, M. S.
spellingShingle	Prombutara, P. Allen, M. S. Flocculation-Related Gene Identification by Whole-Genome Sequencing of Thauera aminoaromatica MZ1T Floc-Defective Mutants
author_facet	Prombutara, P. Allen, M. S.
author_sort	Prombutara, P.
title	Flocculation-Related Gene Identification by Whole-Genome Sequencing of Thauera aminoaromatica MZ1T Floc-Defective Mutants
title_short	Flocculation-Related Gene Identification by Whole-Genome Sequencing of Thauera aminoaromatica MZ1T Floc-Defective Mutants
title_full	Flocculation-Related Gene Identification by Whole-Genome Sequencing of Thauera aminoaromatica MZ1T Floc-Defective Mutants
title_fullStr	Flocculation-Related Gene Identification by Whole-Genome Sequencing of Thauera aminoaromatica MZ1T Floc-Defective Mutants
title_full_unstemmed	Flocculation-Related Gene Identification by Whole-Genome Sequencing of Thauera aminoaromatica MZ1T Floc-Defective Mutants
title_sort	flocculation-related gene identification by whole-genome sequencing of thauera aminoaromatica mz1t floc-defective mutants
description	Thauera aminoaromatica MZ1T, a floc-forming bacterium isolated from an industrial activated-sludge wastewater treatment plant, overproduces exopolysaccharide (EPS), leading to viscous bulking. This phenomenon results in poor sludge settling and dewatering during the clarification process. To identify genes responsible for bacterial flocculation, a whole-genome phenotypic-sequencing technique was applied. Genomic DNA of MZ1T flocculation-deficient mutants was subjected to massively parallel sequencing. The resultant high-quality reads were assembled and compared to the reference genome of the wild type (WT). We identified nine nonsynonymous mutations and one nonsense mutation putatively involved in EPS biosynthesis. Complementation of the nonsense mutation located in an EPS deacetylase gene restored the flocculating phenotype. The Fourier transform infrared (FTIR) spectra of EPS isolated from the wild type showed a reduced C=O peak of the N-acetyl group at 1,665 cm−1 compared to the spectra of MZ1T floc-deficient mutant EPS, suggesting that the WT EPS was partially deacetylated. Gene expression analysis also demonstrated that the putative deacetylase gene transcript increased before flocculation occurred. These data suggest that targeting deacetylation processes via direct chemical modification of EPS or enzyme inhibition may prove useful in combating viscous bulking in this and related bacteria.
publisher	American Society for Microbiology
publishDate	2016
url	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4784049/
_version_	1613549357168066560

Flocculation-Related Gene Identification by Whole-Genome Sequencing of Thauera aminoaromatica MZ1T Floc-Defective Mutants

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