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Freshwater cyanobacteria produce highly toxic secondary metabolites, which can be transported downstream by rivers and waterways into the sea. Estuarine and coastal aquaculture sites exposed to toxic cyanobacteria raise concerns that shellfish may accumulate and transfer cyanotoxins in the food web. This study aims to describe the competitive pattern of uptake and depuration of a wide range of microcystins (MC-LR, MC-LF, MC-LW, MC-LY, [Asp3]-MC-LR/[Dha7]-MC-LR, MC-HilR) and nodularins (NOD cyclic and linear) within the common blue mussel Mytilus edulis exposed to a combined culture of Microcystis aeruginosa and Nodularia spumigena into the coastal environment. Different distribution profiles of MCs/NODs in the experimental system were observed. The majority of MCs/NODs were present intracellularly which is representative of healthy cyanobacterial cultures, with MC-LR and NOD the most abundant analogues. Higher removal rate was observed for NOD (≈96%) compared to MCs (≈50%) from the water phase. Accumulation of toxins in M. edulis was fast, reaching up to 3.4 μg/g shellfish tissue four days after the end of the 3-days exposure period, with NOD (1.72 μg/g) and MC-LR (0.74 μg/g) as the dominant toxins, followed by MC-LF (0.35 μg/g) and MC-LW (0.31 μg/g). Following the end of the exposure period depuration was incomplete after 27 days (0.49 μg/g of MCs/NODs). MCs/NODs were also present in faecal material and extrapallial fluid after 24 h of exposure with MCs the main contributors to the total cyanotoxin load in faecal material and NOD in the extrapallial fluid. Maximum concentration of MCs/NODs accumulated in a typical portion of mussels (20 mussels, ≈4 g each) was beyond greater the acute, seasonal and lifetime tolerable daily intake. Even after 27 days of depuration, consuming mussels harvested during even short term harmful algae blooms in close proximity to shellfish beds might carry a high health risk, highlighting the need for testing.

Marine dinoflagellates produce chemically diverse compounds, with a wide range of biological activity (antimicrobial, anticancer, treatment of neurodegenerative disease along with use as biomedical research tools). Chemical diversity is highlighted by their production of molecules such as the saxitoxin family of alkaloids (C10H17N7O4 - 299 g/mol) to the amphipathic maitotoxin (C164H256O68S2Na2 - 3,422 g/mol), representing one of the largest and most complex secondary metabolites characterised. Dinoflagellates, are most well-known for the production of red tides which are frequently toxic, including okadaic acid and related dinophysistoxins, which are tumour promoters. The mode of action for these phycotoxins, is by specific inhibition of protein phosphatases, enzymes essential in regulation of many cellular processes. Hence, these compounds are being used for vital cell regulation studies. However, the availability of useful amounts of these compounds has restricted research. Chemical synthesis of some compounds such as okadaic acid has been investigated, but the complexity of the molecule resulted in many lengthy steps and achieved only a poor yield. The use of naturally occurring phytoplankton has been investigated as a potential source of these compounds, but it has been shown to be unreliable and impractical. The most practical option is large scale culture with down-stream processing/purification which requires specialist facilities and expertise. This review, describes the biotechnological potential of these organisms and the challenges to achieve useful yields of high quality phycotoxins using Prorocentrum spp. as an example to produce okadaic acid.

Cost-effective, efficient, and sustainable water treatment solutions utilising existing materials and technology will make it easier for low and middle-income countries to adopt them, improving public health. The ability of biochar to mediate and support microbial degradation of contaminants, combined with its carbon-sequestration potential, has attracted attention in recent years. Biochar is a possible candidate for use in cost-effective and sustainable biological water treatment, especially in agrarian economies with easy access to abundant biomass in the form of crop residues and organic wastes. This review evaluates the scope, potential benefits (economic and environmental) and challenges of sustainable biological water treatment using 'Biologically-Enhanced Biochar' or BEB. We discuss the various processes occurring in BEB systems and demonstrate the urgent need to investigate microbial degradation mechanisms. We highlight the need to correlate biochar properties to biofilm development, which can eventually determine process efficiency. We also demonstrate the various opportunities in adopting BEB as a cheaper and more viable alternative in Low and Middle Income Countries and compare it to the current benchmark, 'Biological Activated Carbon'. We focus on the recent advances in the areas of data science, mathematical modelling and molecular biology to systematically and sustainably design BEB filters, unlike the largely empirical design approaches seen in water treatment. 'Sequential biochar systems' are introduced as specially designed end-of-life techniques to lower the environmental impact of BEB filters and examples of their integration into biological water treatment that can fulfil zero waste criteria for BEBs are given.

Microcystins and nodularin are toxic cyanobacterial secondary metabolites produced by cyanobacteria that pose a threat to human health in drinking water. Conventional water treatment methods often fail to remove these toxins. Advanced oxidation processes such as TiO2 photocatalysis have been shown to effectively degrade these compounds. A particular issue that has limited the widespread application of TiO2 photocatalysis for water treatment has been the separation of the nanoparticulate powder from the treated water. A novel catalyst format, TiO2 coated hollow glass spheres (Photospheres™), is far more easily separated from treated water due to its buoyancy. This paper reports the photocatalytic degradation of eleven microcystin variants and nodularin in water using Photospheres™. It was found that the Photospheres™ successfully decomposed all compounds in 5min or less. This was found to be comparable to the rate of degradation observed using a Degussa P25 material, which has been previously reported to be the most efficient TiO2 for photocatalytic degradation of microcystins in water. Furthermore, it was observed that the degree of initial catalyst adsorption of the cyanotoxins depended on the amino acid in the variable positions of the microcystin molecule. The fastest degradation (2min) was observed for the hydrophobic variants (microcystin-LY, -LW, -LF). Suitability of UV-LEDs as an alternative low energy light source was also evaluated.

Microcystins and nodularins, produced naturally by certain species of cyanobacteria, have been found to accumulate in aquatic foodstuffs such as fish and shellfish, resulting in a risk to the health of the seafood consumer. Monitoring of toxins in such organisms for risk management purposes requires the availability of certified matrix reference materials to aid method development, validation and routine quality assurance. This study consequently targeted the preparation of a mussel tissue reference material incurred with a range of microcystin analogues and nodularins. Nine targeted analogues were incorporated into the material as confirmed through liquid chromatography with tandem mass spectrometry (LC-MS/MS), with an additional 15 analogues detected using LC coupled to non-targeted high resolution mass spectrometry (LC-HRMS). Toxins in the reference material and additional source tissues were quantified using LC-MS/MS, two different enzyme-linked immunosorbent assay (ELISA) methods and with an oxidative-cleavage method quantifying 3-methoxy-2-methyl-4-phenylbutyric acid (MMPB). Correlations between the concentrations quantified using the different methods were variable, likely relating to differences in assay cross-reactivities and differences in the abilities of each method to detect bound toxins. A consensus concentration of total soluble toxins determined from the four independent test methods was 2425 ± 575 µg/kg wet weight. A mean 43 ± 9% of bound toxins were present in addition to the freely extractable soluble form (57 ± 9%). The reference material produced was homogenous and stable when stored in the freezer for six months without any post-production stabilization applied. Consequently, a cyanotoxin shellfish reference material has been produced which demonstrates the feasibility of developing certified seafood matrix reference materials for a large range of cyanotoxins and could provide a valuable future resource for cyanotoxin risk monitoring, managemen

Freshwater cyanobacteria produce highly toxic secondary metabolites, which can be transported downstream by rivers and waterways into the sea. Estuarine and coastal aquaculture sites exposed to toxic cyanobacteria raise concerns that shellfish may accumulate and transfer cyanotoxins in the food web. This study aims to describe the competitive pattern of uptake and depuration of a wide range of microcystins (MC-LR, MC-LF, MC-LW, MC-LY, [Asp3]-MC-LR/[Dha7]-MC-LR, MC-HilR) and nodularins (NOD cyclic and linear) within the common blue mussel Mytilus edulis exposed to a combined culture of Microcystis aeruginosa and Nodularia spumigena into the coastal environment. Different distribution profiles of MCs/NODs in the experimental system were observed. The majority of MCs/NODs were present intracellularly which is representative of healthy cyanobacterial cultures, with MC-LR and NOD the most abundant analogues. Higher removal rate was observed for NOD (?96%) compared to MCs (?50%) from the water phase. Accumulation of toxins in M. edulis was fast, reaching up to 3.4 ?g/g shellfish tissue four days after the end of the 3-days exposure period, with NOD (1.72 ?g/g) and MC-LR (0.74 ?g/g) as the dominant toxins, followed by MC-LF (0.35 ?g/g) and MC-LW (0.31 ?g/g). Following the end of the exposure period depuration was incomplete after 27 days (0.49 ?g/g of MCs/NODs). MCs/NODs were also present in faecal material and extrapallial fluid after 24 h of exposure with MCs the main contributors to the total cyanotoxin load in faecal material and NOD in the extrapallial fluid. Maximum concentration of MCs/NODs accumulated in a typical portion of mussels (20 mussels, ?4 g each) was beyond greater the acute, seasonal and lifetime tolerable daily intake. Even after 27 days of depuration, consuming mussels harvested during even short term harmful algae blooms in close proximity to shellfish beds might carry a high health risk, highlighting the need for testing.

Cost-effective, efficient, and sustainable water treatment solutions utilising existing materials and technology will make it easier for low and middle-income countries to adopt them, improving public health. The ability of biochar to mediate and support microbial degradation of contaminants, combined with its carbon-sequestration potential, has attracted attention in recent years. Biochar is a possible candidate for use in cost-effective and sustainable biological water treatment, especially in agrarian economies with easy access to abundant biomass in the form of crop residues and organic wastes. This review evaluates the scope, potential benefits (economic and environmental) and challenges of sustainable biological water treatment using 'Biologically-Enhanced Biochar' or BEB. We discuss the various processes occurring in BEB systems and demonstrate the urgent need to investigate microbial degradation mechanisms. We highlight the need to correlate biochar properties to biofilm development, which can eventually determine process efficiency. We also demonstrate the various opportunities in adopting BEB as a cheaper and more viable alternative in Low and Middle Income Countries and compare it to the current benchmark, 'Biological Activated Carbon'. We focus on the recent advances in the areas of data science, mathematical modelling and molecular biology to systematically and sustainably design BEB filters, unlike the largely empirical design approaches seen in water treatment. 'Sequential biochar systems' are introduced as specially designed end-of-life techniques to lower the environmental impact of BEB filters and examples of their integration into biological water treatment that can fulfil zero waste criteria for BEBs are given.

Microcystins and nodularin are toxic cyanobacterial secondary metabolites produced by cyanobacteria that pose a threat to human health in drinking water. Conventional water treatment methods often fail to remove these toxins. Advanced oxidation processes such as TiO2 photocatalysis have been shown to effectively degrade these compounds. A particular issue that has limited the widespread application of TiO2 photocatalysis for water treatment has been the separation of the nanoparticulate powder from the treated water. A novel catalyst format, TiO2 coated hollow glass spheres (Photospheres™), is far more easily separated from treated water due to its buoyancy. This paper reports the photocatalytic degradation of eleven microcystin variants and nodularin in water using Photospheres™. It was found that the Photospheres™ successfully decomposed all compounds in 5min or less. This was found to be comparable to the rate of degradation observed using a Degussa P25 material, which has been previously reported to be the most efficient TiO2 for photocatalytic degradation of microcystins in water. Furthermore, it was observed that the degree of initial catalyst adsorption of the cyanotoxins depended on the amino acid in the variable positions of the microcystin molecule. The fastest degradation (2min) was observed for the hydrophobic variants (microcystin-LY, -LW, -LF). Suitability of UV-LEDs as an alternative low energy light source was also evaluated.

Marine dinoflagellates produce chemically diverse compounds, with a wide range of biological activity (antimicrobial, anticancer, treatment of neurodegenerative disease along with use as biomedical research tools). Chemical diversity is highlighted by their production of molecules such as the saxitoxin family of alkaloids (C10H17N7O4 - 299 g/mol) to the amphipathic maitotoxin (C164H256O68S2Na2 - 3,422 g/mol), representing one of the largest and most complex secondary metabolites characterised. Dinoflagellates, are most well-known for the production of red tides which are frequently toxic, including okadaic acid and related dinophysistoxins, which are tumour promoters. The mode of action for these phycotoxins, is by specific inhibition of protein phosphatases, enzymes essential in regulation of many cellular processes. Hence, these compounds are being used for vital cell regulation studies. However, the availability of useful amounts of these compounds has restricted research. Chemical synthesis of some compounds such as okadaic acid has been investigated, but the complexity of the molecule resulted in many lengthy steps and achieved only a poor yield. The use of naturally occurring phytoplankton has been investigated as a potential source of these compounds, but it has been shown to be unreliable and impractical. The most practical option is large scale culture with down-stream processing/purification which requires specialist facilities and expertise. This review, describes the biotechnological potential of these organisms and the challenges to achieve useful yields of high quality phycotoxins using Prorocentrum spp. as an example to produce okadaic acid.