Biodegradation of Nodularin by a Microcystin-Degrading Bacterium: Performance, Degradation Pathway, and Potential Application

Currently, studies worldwide have comprehensively recognized the importance of <i>Sphingomonadaceae</i> bacteria and the <i>mlrCABD</i> gene cluster in microcystin (MC) degradation. However, knowledge about their degradation of nodularin (NOD) is still unclear. In this study,...

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Autores principales:	Mengxuan Yuan, Qin Ding, Rongli Sun, Juan Zhang, Lihong Yin, Yuepu Pu
Formato:	article
Lenguaje:	EN
Publicado:	MDPI AG 2021
Materias:	NOD <i>Sphingopyxis</i> biodegradation degradation pathway <i>mlr</i> gene cluster recombinase Medicine R
Acceso en línea:	https://doaj.org/article/8da7b051efc74b28bdff033094b8d9cb
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spelling	oai:doaj.org-article:8da7b051efc74b28bdff033094b8d9cb2021-11-25T19:09:02ZBiodegradation of Nodularin by a Microcystin-Degrading Bacterium: Performance, Degradation Pathway, and Potential Application10.3390/toxins131108132072-6651https://doaj.org/article/8da7b051efc74b28bdff033094b8d9cb2021-11-01T00:00:00Zhttps://www.mdpi.com/2072-6651/13/11/813https://doaj.org/toc/2072-6651Currently, studies worldwide have comprehensively recognized the importance of <i>Sphingomonadaceae</i> bacteria and the <i>mlrCABD</i> gene cluster in microcystin (MC) degradation. However, knowledge about their degradation of nodularin (NOD) is still unclear. In this study, the degradation mechanism of NOD by <i>Sphingopyxis</i> sp. m6, an efficient MC degrader isolated from Lake Taihu, was investigated in several aspects, including degradation ability, degradation products, and potential application. The strain degraded NOD of 0.50 mg/L with a zero-order rate constant of 0.1656 mg/L/d and a half-life of 36 h. The average degradation rate of NOD was significantly influenced by the temperature, pH, and initial toxin concentrations. Moreover, four different biodegradation products, linear NOD, tetrapeptide H-Glu-Mdhb-MeAsp-Arg-OH, tripeptide H-Mdhb-MeAsp-Arg-OH, and dipeptide H-MeAsp-Arg-OH, were identified, of which the latter two are the first reported. Furthermore, the four <i>mlr</i> genes were upregulated during NOD degradation. The microcystinase MlrA encoded by the <i>mlrA</i> gene hydrolyzes the Arg-Adda bond to generate linear NOD as the first step of NOD biodegradation. Notably, recombinant MlrA showed higher degradation activity and stronger environmental adaptability than the wild strain, suggesting future applications in NOD pollution remediation. This research proposes a relatively complete NOD microbial degradation pathway, which lays a foundation for exploring the mechanisms of NOD degradation by MC-degrading bacteria.Mengxuan YuanQin DingRongli SunJuan ZhangLihong YinYuepu PuMDPI AGarticleNOD<i>Sphingopyxis</i>biodegradationdegradation pathway<i>mlr</i> gene clusterrecombinaseMedicineRENToxins, Vol 13, Iss 813, p 813 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	NOD <i>Sphingopyxis</i> biodegradation degradation pathway <i>mlr</i> gene cluster recombinase Medicine R
spellingShingle	NOD <i>Sphingopyxis</i> biodegradation degradation pathway <i>mlr</i> gene cluster recombinase Medicine R Mengxuan Yuan Qin Ding Rongli Sun Juan Zhang Lihong Yin Yuepu Pu Biodegradation of Nodularin by a Microcystin-Degrading Bacterium: Performance, Degradation Pathway, and Potential Application
description	Currently, studies worldwide have comprehensively recognized the importance of <i>Sphingomonadaceae</i> bacteria and the <i>mlrCABD</i> gene cluster in microcystin (MC) degradation. However, knowledge about their degradation of nodularin (NOD) is still unclear. In this study, the degradation mechanism of NOD by <i>Sphingopyxis</i> sp. m6, an efficient MC degrader isolated from Lake Taihu, was investigated in several aspects, including degradation ability, degradation products, and potential application. The strain degraded NOD of 0.50 mg/L with a zero-order rate constant of 0.1656 mg/L/d and a half-life of 36 h. The average degradation rate of NOD was significantly influenced by the temperature, pH, and initial toxin concentrations. Moreover, four different biodegradation products, linear NOD, tetrapeptide H-Glu-Mdhb-MeAsp-Arg-OH, tripeptide H-Mdhb-MeAsp-Arg-OH, and dipeptide H-MeAsp-Arg-OH, were identified, of which the latter two are the first reported. Furthermore, the four <i>mlr</i> genes were upregulated during NOD degradation. The microcystinase MlrA encoded by the <i>mlrA</i> gene hydrolyzes the Arg-Adda bond to generate linear NOD as the first step of NOD biodegradation. Notably, recombinant MlrA showed higher degradation activity and stronger environmental adaptability than the wild strain, suggesting future applications in NOD pollution remediation. This research proposes a relatively complete NOD microbial degradation pathway, which lays a foundation for exploring the mechanisms of NOD degradation by MC-degrading bacteria.
format	article
author	Mengxuan Yuan Qin Ding Rongli Sun Juan Zhang Lihong Yin Yuepu Pu
author_facet	Mengxuan Yuan Qin Ding Rongli Sun Juan Zhang Lihong Yin Yuepu Pu
author_sort	Mengxuan Yuan
title	Biodegradation of Nodularin by a Microcystin-Degrading Bacterium: Performance, Degradation Pathway, and Potential Application
title_short	Biodegradation of Nodularin by a Microcystin-Degrading Bacterium: Performance, Degradation Pathway, and Potential Application
title_full	Biodegradation of Nodularin by a Microcystin-Degrading Bacterium: Performance, Degradation Pathway, and Potential Application
title_fullStr	Biodegradation of Nodularin by a Microcystin-Degrading Bacterium: Performance, Degradation Pathway, and Potential Application
title_full_unstemmed	Biodegradation of Nodularin by a Microcystin-Degrading Bacterium: Performance, Degradation Pathway, and Potential Application
title_sort	biodegradation of nodularin by a microcystin-degrading bacterium: performance, degradation pathway, and potential application
publisher	MDPI AG
publishDate	2021
url	https://doaj.org/article/8da7b051efc74b28bdff033094b8d9cb
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Biodegradation of Nodularin by a Microcystin-Degrading Bacterium: Performance, Degradation Pathway, and Potential Application

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