Microcystin-degrading bacteria affect mcyD expression and microcystin synthesis in Microcystis spp.

Zhu, Lin; Zuo, Jun; Song, Lirong; Gan, Nanqin

doi:10.1016/j.jes.2015.06.016

Cited by 15 publications

(5 citation statements)

References 45 publications

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“…Cyanobacteria treatment efficiency improvement requires an understanding of the cyanobacterial composition structure in response to treatment processes [21]. Molecular methods have been used to study the fate of the microbial community, including cyanobacteria, within different conditions [5,22]. Molecular methods can overcome the challenges of microscopic cell counts such as time and qualified person requirements, as well as changes in biovolumes during analyses [23][24][25].…”

Section: Introductionmentioning

confidence: 99%

Diversity Assessment of Toxic Cyanobacterial Blooms during Oxidation

Moradinejad

Trigui

Maldonado

et al. 2020

Toxins

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Fresh-water sources of drinking water are experiencing toxic cyanobacterial blooms more frequently. Chemical oxidation is a common approach to treat cyanobacteria and their toxins. This study systematically investigates the bacterial/cyanobacterial community following chemical oxidation (Cl2, KMnO4, O3, H2O2) using high throughput sequencing. Raw water results from high throughput sequencing show that Proteobacteria, Actinobacteria, Cyanobacteria and Bacteroidetes were the most abundant phyla. Dolichospermum, Synechococcus, Microcystis and Nostoc were the most dominant genera. In terms of species, Dolichospermum sp.90 and Microcystis aeruginosa were the most abundant species at the beginning and end of the sampling, respectively. A comparison between the results of high throughput sequencing and taxonomic cell counts highlighted the robustness of high throughput sequencing to thoroughly reveal a wide diversity of bacterial and cyanobacterial communities. Principal component analysis of the oxidation samples results showed a progressive shift in the composition of bacterial/cyanobacterial communities following soft-chlorination with increasing common exposure units (CTs) (0–3.8 mg·min/L). Close cyanobacterial community composition (Dolichospermum dominant genus) was observed following low chlorine and mid-KMnO4 (287.7 mg·min/L) exposure. Our results showed that some toxin producing species may persist after oxidation whether they were dominant species or not. Relative persistence of Dolichospermum sp.90 was observed following soft-chlorination (0.2–0.6 mg/L) and permanganate (5 mg/L) oxidation with increasing oxidant exposure. Pre-oxidation using H2O2 (10 mg/L and one day contact time) caused a clear decrease in the relative abundance of all the taxa and some species including the toxin producing taxa. These observations suggest selectivity of H2O2 to provide an efficient barrier against toxin producing cyanobacteria entering a water treatment plant.

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Section: Introductionmentioning

confidence: 99%

Diversity Assessment of Toxic Cyanobacterial Blooms during Oxidation

Moradinejad

Trigui

Maldonado

et al. 2020

Toxins

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“…The MC degradation process mediated by wild bacteria always show low efficiency and requires an adaptation period [ 45 , 46 ]. By contrast, heterologous expression of MlrA could greatly enhance the yields and the biodegradation abilities of MCs, as the MlrA activity of the cell-free extract from heterologous expression was 6800 times greater than that from the natural expression [ 32 ].…”

Section: Discussionmentioning

confidence: 99%

“…The pH and temperature of environmental water bodies fluctuate frequently during the cyanobacterial bloom period; however, these two parameters are crucial for MlrA activity [ 32 , 46 , 48 , 49 ]. In this study, the degradation activities of heterologously expressed MlrA were tested under different pH and temperature conditions, revealing the optimal conditions for MC degradation as 30 °C and pH 8.0, which were slightly different to those determined by Dziga [ 48 ] (i.e., pH 7.5 and 20 °C).…”

Section: Discussionmentioning

confidence: 99%

Simultaneous Removal of the Freshwater Bloom-Forming Cyanobacterium Microcystis and Cyanotoxin Microcystins via Combined Use of Algicidal Bacterial Filtrate and the Microcystin-Degrading Enzymatic Agent, MlrA

et al. 2021

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Freshwater cyanobacterial blooms (e.g., Microcystis blooms) constitute a major global environmental problem because of their risks to public health and aquatic ecological systems. Current physicochemical treatments of toxic cyanobacteria cause the significant release of cyanotoxin microcystins from damaged cells. Biological control is a promising eco-friendly technology to manage harmful cyanobacteria and cyanotoxins. Here, we demonstrated an efficient biological control strategy at the laboratory scale to simultaneously remove Microcystis and microcystins via the combined use of the algicidal bacterial filtrate and the microcystin-degrading enzymatic agent. The algicidal indigenous bacterium Paenibacillus sp. SJ-73 was isolated from the sediment of northern Lake Taihu, China, and the microcystin-degrading enzymatic agent (MlrA) was prepared via the heterologous expression of the mlrA gene in the indigenous microcystin-degrading bacterium Sphingopyxis sp. HW isolated from Lake Taihu. The single use of a fermentation filtrate (5%, v/v) of Paenibacillus sp. SJ-73 for seven days removed the unicellular Microcystis aeruginosa PCC 7806 and the native colonial Microcystis strain TH1701 in Lake Taihu by 84% and 92%, respectively, whereas the single use of MlrA removed 85% of microcystins. Used in combination, the fermentation filtrate and MlrA removed Microcystis TH1701 and microcystins by 92% and 79%, respectively. The present biological control thus provides an important technical basis for the further development of safe, efficient, and effective measures to manage Microcystis blooms and microcystins in natural waterbodies.

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“…Sphingomonas spp., a microcystin-degrading bacterium, was detected to upregulate mcyD expression in Microcystis spp. [41]. Diphylleia rotans, a zooplankton, was also found to elevate microcystin production of M. aeruginosa [42].…”

Section: Discussionmentioning

confidence: 99%

Corresponding Responses of Microcystis aeruginosa to <i>Eichhornia crassipes</i> (Mart.) Solms Stress

Qing¹,

Han²,

Zhang³

et al. 2020

Pol. J. Environ. Stud.

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As global climate changes and water eutrophication are aggravated, cyanobacterial blooms has become a worldwide ecological problem and poses risks to public health [1]. Microcystis aeruginosa may originate from the African continent and has depersed into Asia, Europe and America [2]. Toxic Microcystis aeruginosa is the most primary bloom-forming cyanobacteria in eutrophic freshwaters [3-4]. It produces microcystins that can lead to poisoning, cancer and even death of humans and animals [5]. The Toledo drinking water crisis in USA, the Wuxi drinking water crisis in China and the recreational water risk in Portugal have caused public health concerns [6-8]. Many methods for controlling cyanobacterial blooms have been

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Microcystin-degrading bacteria affect mcyD expression and microcystin synthesis in Microcystis spp.

Cited by 15 publications

References 45 publications

Diversity Assessment of Toxic Cyanobacterial Blooms during Oxidation

Diversity Assessment of Toxic Cyanobacterial Blooms during Oxidation

Simultaneous Removal of the Freshwater Bloom-Forming Cyanobacterium Microcystis and Cyanotoxin Microcystins via Combined Use of Algicidal Bacterial Filtrate and the Microcystin-Degrading Enzymatic Agent, MlrA

Corresponding Responses of Microcystis aeruginosa to <i>Eichhornia crassipes</i> (Mart.) Solms Stress

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