Biotransformation of the Cyanobacterial Hepatotoxin Microcystin-LR, as Determined by HPLC and Protein Phosphatase Bioassay

Lam, Angeline K.-Y.; Fedorak, Phillip M.; Prepas, E. E.

doi:10.1021/es00001a030

Cited by 82 publications

(34 citation statements)

References 16 publications

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“…Hydrogen peroxide promotes cell lysis, and if cyanotoxins are not degraded by the chemical itself, their degradation by natural mechanisms is of significance. It has been demonstrated that the bacteria found in activated sludge effluent (produced during wastewater treatment) are able to degrade cyanotoxins, particularly microcystin species (Ho et al, 2010;Lam et al, 1995). In particular, Ho et al (2010) compared the degradation rates of dissolved microcystins in both fresh activated sludge treated effluent and axenic tertiary-activated sludge treated effluent within the laboratory.…”

Section: Introductionmentioning

confidence: 99%

Cyanobacterial and microcystins dynamics following the application of hydrogen peroxide to waste stabilisation ponds

Barrington

Ghadouani

Ivey

2013

Hydrol. Earth Syst. Sci.

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Abstract. Cyanobacteria and cyanotoxins are a risk to human and ecological health, and a hindrance to biological wastewater treatment. This study investigated the use of hydrogen peroxide (H 2 O 2 ) for the removal of cyanobacteria and cyanotoxins from within waste stabilization ponds (WSPs). The daily dynamics of cyanobacteria and microcystins (commonly occurring cyanotoxins) were examined following the addition of H 2 O 2 to wastewater within both the laboratory and at the full scale within a maturation WSP, the final pond in a wastewater treatment plant. Hydrogen peroxide treatment at concentrations ≥ 0.1 mg H 2 O 2 µg −1 total phytoplankton chlorophyll a led to the lysis of cyanobacteria, in turn releasing intracellular microcystins to the dissolved state. In the full-scale trial, dissolved microcystins were then degraded to negligible concentrations by H 2 O 2 and environmental processes within five days. A shift in the phytoplankton assemblage towards beneficial Chlorophyta species was also observed within days of H 2 O 2 addition. However, within weeks, the Chlorophyta population was significantly reduced by the re-establishment of toxic cyanobacterial species. This re-establishment was likely due to the inflow of cyanobacteria from ponds earlier in the treatment train, suggesting that whilst H 2 O 2 may be a suitable short-term management technique, it must be coupled with control over inflows if it is to improve WSP performance in the longer term.

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Section: Introductionmentioning

confidence: 99%

Cyanobacterial and microcystins dynamics following the application of hydrogen peroxide to waste stabilisation ponds

Barrington

Ghadouani

Ivey

2013

Hydrol. Earth Syst. Sci.

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“…Aerobic biodegradation has been considered to be the main attenuation mechanism for MCs, and this process was reported to occur in diverse ecosystems, such as rivers [12], sand filters [11], reservoirs [20,21], coastal lagoons [22], lakes [17,23,24], and sewage effluent [25]. Bacterial strains of Sphingpoyxis sp.…”

Section: Introductionmentioning

confidence: 99%

Microcystin-LR biodegradation by Sphingopyxis sp. USTB-05

Xiao

Yan

Wang

et al. 2010

Front. Environ. Sci. Eng. China

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A promising bacterial strain for biodegrading microcystin-LR (MC-LR) as the sole carbon and nitrogen source was successfully isolated from Lake Dianchi, China. The strain was identified as Sphingopyxis sp. USTB-05, which was the first isolated MCs-biodegrading Sphingopyxis sp. in China. The average biodegradation rate of MC-LR by Sphingopyxis sp. USTB-05 was 28.8 mg$L -1 per day, which was apparently higher than those of other bacteria reported so far. The optimal temperature and pH for both strain USTB-05 growth and MC-LR biodegradation were 30°C and 7.0, respectively. The release of MC-LR from the cyanobacterial cells collected from Lake Guishui and the biodegradation of MC-LR by both strain and cell-free extract (CE) were investigated. The results indicated that MC-LR with the initial concentration of 4.0 mg$L -1 in water was biodegraded by Sphingopyxis sp. USTB-05 within 4 d, while MC-LR with the initial concentration of 28.8 mg$L -1 could be completely removed in 3 h by CE of Sphingopyxis sp. USTB-05 containing 350 mg$L -1 protein. During enzymatic biodegradation of MC-LR, two intermediate metabolites and a dead-end product were observed on an HPLC chromatogram. Moreover, the similar scanning profiles of MC-LR and its metabolic products indicate that the Adda side-chain of MC-LR was kept intact in all products.

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“…The lack of direct connection between microcystins in scums and the amount of dissolved microcystins in water can be affected by various factors, including mixing due to wind action or currents 29 . Furthermore, microcystins may be removed by many factors in the natural environmental condition, for example, biodegradation by bacteria in water and sediments 30 , photochemical breakdown and isomerisation 31 , and sorption onto sediment particles 32 . This study did not analyse microcystins extracted from Microcystis scum in a manner parallel to the microcystins in water and Microcystis amount because of many variances in the natural environmental condition mentioned previously.…”

Section: Dissolved Microcystins) Collected Frommentioning

confidence: 99%

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Prommana¹,

Peerapornpisal²,

Whangchai³

et al. 2006

ScienceAsia

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ABSTRACT:The presence of cyanobacterially-produced microcystins (cyclic peptide hepatotoxins) was determined by analysis of Microcystis spp. in scum and water samples collected from a surface cyanobacterial bloom at a giant freshwater prawn (Macrobrachium rosenbergii) farm in Teung District, Chiang Rai Province, in northern Thailand during March to August 2004. M. aeruginasa and M. wesenbergii were the dominant species of cyanobacteria at concentrations between 850,000±190,000 and 302,000±73,000 colonies l -1 . Microcystins were present at 0.44±0.020 g kg -1 dry weight with microcystin-LR and microcystin-RR as the dominant microcystin types, accounting for 45% and 48% of the total microcystins detected, respectively. Microcystins in pond water were present at between 2.2±3.0 µg l -1 and 9.4±2.0 µg l -1 . Total microcystin concentrations in water seemed to be positively correlated with the number of Microcystis colonies. A decrease of microcystins in water was observed from April to August 2004, which may have resulted from removal by mechanisms not examined in this study. The total microcystin in water was slightly negatively correlated with total culturable bacteria numbers. Microcystis spp. colony number showed a significant negative correlation with soluble reactive phosphorus (r = -0.98, p<0.05). Nitrate-N, ammonium-N and soluble reactive phosphorus concentrations were between 1.2-1.9, 0.85-1.15 and 0.9-1.1 mg l -1 , respectively. Phosphorus concentrations were higher than the permitted limit for waste water from a fishery farm (less than 0.4 mg l -1 ). This study suggested that surface blooms of Microcystis species in cultivation ponds may present a risk for microcystin bioaccumulation in prawns, either directly or via other organisms in the food web.

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Biotransformation of the Cyanobacterial Hepatotoxin Microcystin-LR, as Determined by HPLC and Protein Phosphatase Bioassay

Cited by 82 publications

References 16 publications

Cyanobacterial and microcystins dynamics following the application of hydrogen peroxide to waste stabilisation ponds

Cyanobacterial and microcystins dynamics following the application of hydrogen peroxide to waste stabilisation ponds

Microcystin-LR biodegradation by Sphingopyxis sp. USTB-05

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