Bacterial degradation of microcystin toxins within a biologically active sand filter

Ho, Lionel; Meyn, Thomas; Keegan, Alexandra; Hoefel, Daniel; Brookes, Justin D.; Saint, Christopher P.; Newcombe, Gayle

doi:10.1016/j.watres.2005.12.009

Cited by 136 publications

(86 citation statements)

References 28 publications

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“…More than 60 different analogues of MCs have been isolated from natural blooms or laboratory cultures of cyanobacteria [9] in which the most common and toxic analog is microcystin-LR (MC-LR) [10][11][12][13]. (2S,3S,8S,9S)-3-amino-9-methoxy-2,4,6-trimethyl-10-phenyldeca-4,6-dienoic dienoic acid (Adda) as one of the constituent amino acids in MC-LR is essential for the characteristic biologic activities of MCs [14,15].…”

Section: Introductionmentioning

confidence: 99%

“…The stable cyclic structure of MCs has presented many challenges to traditional water treatment technologies [16] where conventional processes, such as adsorption [17], ozone oxidation [18], photo-degradation [14], and electrochemical oxidation [19], have limited effect on their removal [11]. 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].…”

Section: Introductionmentioning

confidence: 99%

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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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Section: Introductionmentioning

confidence: 99%

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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“…Several experiments indicated that biologically active filters (granular activated carbon and sand) may be an attractive water treatment option [17]- [19]. It has been documented that MC removal in this system is not only due to physical processes but mainly to biological degradation.…”

Section: Discussionmentioning

confidence: 99%

Genetically Engineered Bacteria Immobilized in Alginate as an Option of Cyanotoxins Removal

Dziga¹,

Sworzen²,

Władyka³

et al. 2013

IJESD

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“…Concentrations of dissolved MCs tended to decrease during the further steps of the water treatment, which might be attributed to their biodegradation during rapid sand filtration (Ho et al, 2006) or chlorination (Merel et al, 2010). However, the applied water treatment procedures in some instances actually resulted in the increase of dissolved MC concentrations even in the final treated water (Weija, January 24 th , and Kpong, March 24 th ), which indicates that the conventional treatment procedures are only partially effective for removal of dissolved toxins.…”

Section: Discussionmentioning

confidence: 99%

Cyanobacteria and microcystin contamination in untreated and treated drinking water in Ghana

Addico¹,

Hardege²,

Kohoutek³

et al. 2017

Adv Ocean Limnol

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Although cyanobacterial blooms and cyanotoxins represent a worldwide-occurring phenomenon, there are large differences among different countries in cyanotoxin-related human health risk assessment, management practices and policies. While national standards, guideline values and detailed regulatory frameworks for effective management of cyanotoxin risks have been implemented in many industrialized countries, the extent of cyanobacteria occurrence and cyanotoxin contamination in certain geographical regions is underreported and not very well understood. Such regions include major parts of tropical West and Central Africa, a region constisting of more than 25 countries occupying an area of 12 million km 2 , with a total population of 500 milion people. Only few studies focusing on cyanotoxin occurrence in this region have been published so far, and reports dealing specifically with cyanotoxin contamination in drinking water are extremely scarce. In this study, we report seasonal data on cyanobacteria and microcystin (MC) contamination in drinking water reservoirs and adjacent treatment plants located in Ghana, West Africa. During January-June 2005, concentrations of MCs were monitored in four treatment plants supplying drinking water to major metropolitan areas in Ghana: the treatment plants Barekese and Owabi, which serve Kumasi Metropolitan Area, and the plants Kpong and Weija, providing water for Accra-Tema Metropolitan Area. HPLC analyses showed that 65% samples of raw water at the intake of the treatment plants contained intracellular MCs (maximal detected concentration was 8.73 µg L -1 ), whereas dissolved toxins were detected in 33% of the samples. Significant reduction of cyanobacterial cell counts and MC concentrations was achieved during the entire monitoring period by the applied conventional water treatment methods (alum flocculation, sedimentation, rapid sand filtration and chlorination), and MC concentration in the final treated water never exceeded 1 µg L -1 (WHO guideline limit for MC-LR in drinking water). However, cyanobacterial cells (93-3,055 cell mL -1 ) were frequently found in the final treated water and intracellular MCs were detected in 17% of the samples (maximal concentration 0.61 µg L -1 ), while dissolved MCs were present in 14% of the final treated water samples (maximal concentration 0.81 µg L -1 ). It indicates a borderline efficiency of the water treatment, thus MC concentrations in drinking water might exceed the WHO guideline limit if the treatment efficiency gets compromised. In addition, MC concentrations found in the raw water might represent significant human health risks for people living in areas with only a limited access to the treated or underground drinking water.

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Bacterial degradation of microcystin toxins within a biologically active sand filter

Cited by 136 publications

References 28 publications

Microcystin-LR biodegradation by Sphingopyxis sp. USTB-05

Microcystin-LR biodegradation by Sphingopyxis sp. USTB-05

Genetically Engineered Bacteria Immobilized in Alginate as an Option of Cyanotoxins Removal

Cyanobacteria and microcystin contamination in untreated and treated drinking water in Ghana

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