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Nicholas A Paul - One of the best experts on this subject based on the ideXlab platform.
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Bioremediation of Aluminium from the Waste Water of a Conventional Water Treatment Plant Using the Freshwater Macroalga Oedogonium
MDPI AG, 2018Co-Authors: David A. Roberts, Rocky De Nys, Laura Shiels, Julian Tickle, Nicholas A PaulAbstract:Conventional water treatment processes use aluminium sulphate (alum) as a coagulant in the production of potable water. While alum is an inexpensive and reliable means of treating water, the process generates waste water containing dissolved Al. This waste water is primarily dealt with via on-site retention. In this study we investigate the cultivation of the freshwater macroalga Oedogonium as a means to sequester dissolved Al from waste water from a conventional water treatment plant. Furthermore, we examine the use of CO2 to manipulate the pH of cultivation as a means of enhancing the sequestration of Al by either increasing the productivity of Oedogonium or increasing the bioavailability of Al in the waste water. The relative bioavailability of Al under conditions of CO2 and no-CO2 provision was contrasted by comparing Al uptake by Diffusive Gradients in Thin Films (DGTs). Oedogonium was able to grow rapidly in the waste water (12 g dry weight m−2 day−1) while consistently sequestering Al. The Oedogonium-treated waste water had a sufficiently low Al concentration that it could be used in unrestricted irrigation in the surrounding region. When CO2 was added to the waste water containing concentrations of Al up to 8 mg L−1, there was a slight increase (~10%) in the rate of sequestration of Al by Oedogonium relative to waste water not receiving CO2. This was due to two concurrent processes. The provision of CO2 increased the productivity of Oedogonium by 15% and the bioavailability of Al by up to 200%, as measured by the DGTs. Despite this strong effect of CO2 on Al bioavailability, the increase in Al sequestration by Oedogonium when CO2 was provided was modest (~10%). Al was sequestered by Oedogonium to concentrations below permissible limits for discharge without the need for the addition CO2. The cultivation of Oedogonium in waste water from conventional treatments plants can simultaneously treat waste water for re-use and provide a biomass source for value-added applications
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Identification and biological activities of carotenoids from the freshwater alga Oedogonium intermedium.
Food chemistry, 2017Co-Authors: Na Wang, Nicholas A Paul, Yuki Manabe, Tatsuya Sugawara, Jian ZhaoAbstract:Abstract The chemical and biological properties of carotenoids in the freshwater alga Oedogonium intermedium were investigated in this study. Carotenoids were extracted from the alga by dichloromethane and purified by saponification. The carotenoid content was determined both spectrometrically and by HPLC, the carotenoids identified by HPLC-PDA-APCI-IT-TOF-MS and the extracts analysed for several health-related bioactivities. The crude and saponified extracts contained 3,411.2 ± 20.7 and 2,929.6 ± 5.9 µg carotenoids/g dry algal biomass, respectively. Seven major carotenoids were identified, namely neoxanthin, 9′- cis -neoxanthin, loroxanthin, violaxanthin, lutein, α-carotene and β-carotene, which were present in similar amounts in the alga. Both the crude and saponified carotenoid extracts exhibited significant antioxidant activities as well as potent inhibitory effects against several metabolically important enzymes including α-amylase, α-glucosidase, pancreatic lipase and hyaluronidase, but they were poor inhibitors of angiotensin converting enzyme (ACE). Oedogonium could be an important new source of carotenoids, specifically loroxanthin, which is lacking in terrestrial plants.
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Selecting Reliable and Robust Freshwater Macroalgae for Biomass Applications
2016Co-Authors: Rebecca J. Lawton, Rocky De Nys, Nicholas A PaulAbstract:Intensive cultivation of freshwater macroalgae is likely to increase with the development of an algal biofuels industry and algal bioremediation. However, target freshwater macroalgae species suitable for large-scale intensive cultivation have not yet been identified. Therefore, as a first step to identifying target species, we compared the productivity, growth and biochemical composition of three species representative of key freshwater macroalgae genera across a range of cultivation conditions. We then selected a primary target species and assessed its competitive ability against other species over a range of stocking densities. Oedogonium had the highest productivity (8.0 g ash free dry weight m22 day21), lowest ash content (3–8%), lowest water content (fresh weigh: dry weight ratio of 3.4), highest carbon content (45%) and highest bioenergy potential (higher heating value 20 MJ/kg) compared to Cladophora and Spirogyra. The higher productivity of Oedogonium relative to Cladophora and Spirogyra was consistent when algae were cultured with and without the addition of CO2 across three aeration treatments. Therefore, Oedogonium was selected as our primary target species. The competitive ability of Oedogonium was assessed by growing it in bi-cultures and polycultures with Cladophora and Spirogyra over a range of stocking densities. Cultures were initially stocked with equal proportions of each species, but after three weeks of growth the proportion of Oedogonium had increased to at least 96 % (67 S.E.) in Oedogonium-Spirogyra bi-cultures, 86 % (616 S.E.) in Oedogonium-Cladophora bi-cultures and 82 % (618 S.E.) in polycultures. The high productivity, bioenergy potential an
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Removing Constraints on the Biomass Production of Freshwater Macroalgae by Manipulating Water Exchange to Manage Nutrient Flux
2016Co-Authors: Andrew J Cole, Rocky De Nys, Nicholas A PaulAbstract:Freshwater macroalgae represent a largely overlooked group of phototrophic organisms that could play an important role within an industrial ecology context in both utilising waste nutrients and water and supplying biomass for animal feeds and renewable chemicals and fuels. This study used water from the intensive aquaculture of freshwater fish (Barramundi) to examine how the biomass production rate and protein content of the freshwater macroalga Oedogonium responds to increasing the flux of nutrients and carbon, by either increasing water exchange rates or through the addition of supplementary nitrogen and CO2. Biomass production rates were highest at low flow rates (0.1–1 vol.day 21) using raw pond water. The addition of CO2 to cultures increased biomass production rates by between 2 and 25 % with this effect strongest at low water exchange rates. Paradoxically, the addition of nitrogen to cultures decreased productivity, especially at low water exchange rates. The optimal culture of Oedogonium occurred at flow rates of between 0.5–1 vol.day21, where uptake rates peaked at 1.09 g.m22.day21 for nitrogen and 0.13 g.m22.day21 for phosphorous. At these flow rates Oedogonium biomass had uptake efficiencies of 75.2 % for nitrogen and 22.1 % for phosphorous. In this study a nitrogen flux of 1.45 g.m22.day21 and a phosphorous flux of 0.6 g.m22.day21 was the minimum required to maintain the growth of Oedogonium at 16–17 g DW.m22.day21 and a crude protein content of 25%. A simple model of minimum inputs shows tha
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dose response effects of asparagopsis taxiformis and Oedogonium sp on in vitro fermentation and methane production
Journal of Applied Phycology, 2016Co-Authors: Lorenna Machado, Nicholas A Paul, Marie Magnusson, Nigel William TomkinsAbstract:This study aimed to identify the optimal doses of the macroalgae Asparagopsis taxiformis and Oedogonium sp., individually and in combination, which would decrease the in vitro production of methane while minimizing adverse effects on fermentation, using rumen inoculant from Bos indicus steers. The dose-response experiment evaluated ten doses of Asparagopsis [ranging from 0 to 16.7 % of the organic matter (OM) incubated] and seven doses of Oedogonium (ranging from 0 to 100 % OM) using Rhodes grass hay as a basal substrate. Asparagopsis was highly effective in decreasing the production of methane with a reduction of 99 % at doses as low as 2 % OM basis. However, a dose of 2 % OM also decreased the production of volatile fatty acids (VFA). Oedogonium was less effective with doses ≥50 % OM significantly decreasing the production of methane. A combination of Asparagopsis (2 % OM) and Oedogonium (25 and 50 % OM) continued to suppress the production of methane, independent of the inclusion rate of Oedogonium. The effectiveness of Asparagopsis demonstrates its potential for the mitigation of methane emissions from ruminants at inclusion rates of ≤2 % OM. Oedogonium is a potential feed supplement due to its nutritional value, but supplements ≤25 % OM are recommended to avoid adverse effects on apparent in vitro fermentation.
Rocky De Nys - One of the best experts on this subject based on the ideXlab platform.
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Evaluating the performance of freshwater macroalgae in the bioremediation of nutrient-enriched water in temperate environments
Journal of Applied Phycology, 2019Co-Authors: J. M. Valero-rodriguez, Rocky De Nys, Tim Dempster, Stephen E. Swearer, A. J. ColeAbstract:Algal bioremediation can significantly improve the quality of wastewater by assimilating nutrients. However, the efficiency and stability of this approach depends on identifying suitable algae based on their biomass productivity and ability to outcompete less desirable algae. Here, we compare the productivity and competitive ability of three taxa of filamentous macroalgae under the seasonal light and temperature conditions experienced in temperate environments, including extremes of heat and cold. Specific growth rate was greatest for the tropical isolate of Oedogonium under summer conditions (36–40%; P 90% for both) and, in its absence, Hyalotheca also dominate over Oedogonium. Our results suggest that rather than finding an optimal taxon for all four seasons, the best decision for maximising stable biomass production will require either seasonal rotation of algae, or bi-cultures of the most dominant ones. Further, prioritising competition over production when selecting freshwater algae for wastewater bioremediation is likely to prove the most successful strategy.
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Bioremediation of Aluminium from the Waste Water of a Conventional Water Treatment Plant Using the Freshwater Macroalga Oedogonium
MDPI AG, 2018Co-Authors: David A. Roberts, Rocky De Nys, Laura Shiels, Julian Tickle, Nicholas A PaulAbstract:Conventional water treatment processes use aluminium sulphate (alum) as a coagulant in the production of potable water. While alum is an inexpensive and reliable means of treating water, the process generates waste water containing dissolved Al. This waste water is primarily dealt with via on-site retention. In this study we investigate the cultivation of the freshwater macroalga Oedogonium as a means to sequester dissolved Al from waste water from a conventional water treatment plant. Furthermore, we examine the use of CO2 to manipulate the pH of cultivation as a means of enhancing the sequestration of Al by either increasing the productivity of Oedogonium or increasing the bioavailability of Al in the waste water. The relative bioavailability of Al under conditions of CO2 and no-CO2 provision was contrasted by comparing Al uptake by Diffusive Gradients in Thin Films (DGTs). Oedogonium was able to grow rapidly in the waste water (12 g dry weight m−2 day−1) while consistently sequestering Al. The Oedogonium-treated waste water had a sufficiently low Al concentration that it could be used in unrestricted irrigation in the surrounding region. When CO2 was added to the waste water containing concentrations of Al up to 8 mg L−1, there was a slight increase (~10%) in the rate of sequestration of Al by Oedogonium relative to waste water not receiving CO2. This was due to two concurrent processes. The provision of CO2 increased the productivity of Oedogonium by 15% and the bioavailability of Al by up to 200%, as measured by the DGTs. Despite this strong effect of CO2 on Al bioavailability, the increase in Al sequestration by Oedogonium when CO2 was provided was modest (~10%). Al was sequestered by Oedogonium to concentrations below permissible limits for discharge without the need for the addition CO2. The cultivation of Oedogonium in waste water from conventional treatments plants can simultaneously treat waste water for re-use and provide a biomass source for value-added applications
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The freshwater macroalga Oedogonium intermedium can meet the nutritional requirements of the herbivorous fish Ancistrus cirrhosus
Algal Research, 2017Co-Authors: Matthew J. Vucko, Andrew J Cole, Jonathan A. Moorhead, Josiah Pit, Rocky De NysAbstract:Abstract The macroalga Oedogonium intermedium has a diverse elemental profile, high energy potential, high lipid content, a high proportion of essential amino acids and a total concentration of protein with the potential to meet the nutritional requirements of herbivorous fishes. The aim of this study was to assess growth, condition, colouration and reproductive output in an herbivorous ornamental fish. The catfish Ancistrus cirrhosus was fed one of three pelletised experimental feeds, Oedogonium , a formulated commercial feed and a 50:50 mix of the two, over a 10 month trial. After 10 months, fish that were fed exclusively on Oedogonium had equivalent growth rates, body condition, colouration, fecundity and fertilisation rates compared to those fed the commercial and mixed feeds. The absence of any major differences of these characteristics between feeds, especially between Oedogonium and the commercial feed, demonstrates the viability of Oedogonium as a feed, or significant feed ingredient, for this herbivorous fish. As such, linking the cultivation of Oedogonium with the production of herbivorous fish may provide an ideal application for Oedogonium .
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Selecting Reliable and Robust Freshwater Macroalgae for Biomass Applications
2016Co-Authors: Rebecca J. Lawton, Rocky De Nys, Nicholas A PaulAbstract:Intensive cultivation of freshwater macroalgae is likely to increase with the development of an algal biofuels industry and algal bioremediation. However, target freshwater macroalgae species suitable for large-scale intensive cultivation have not yet been identified. Therefore, as a first step to identifying target species, we compared the productivity, growth and biochemical composition of three species representative of key freshwater macroalgae genera across a range of cultivation conditions. We then selected a primary target species and assessed its competitive ability against other species over a range of stocking densities. Oedogonium had the highest productivity (8.0 g ash free dry weight m22 day21), lowest ash content (3–8%), lowest water content (fresh weigh: dry weight ratio of 3.4), highest carbon content (45%) and highest bioenergy potential (higher heating value 20 MJ/kg) compared to Cladophora and Spirogyra. The higher productivity of Oedogonium relative to Cladophora and Spirogyra was consistent when algae were cultured with and without the addition of CO2 across three aeration treatments. Therefore, Oedogonium was selected as our primary target species. The competitive ability of Oedogonium was assessed by growing it in bi-cultures and polycultures with Cladophora and Spirogyra over a range of stocking densities. Cultures were initially stocked with equal proportions of each species, but after three weeks of growth the proportion of Oedogonium had increased to at least 96 % (67 S.E.) in Oedogonium-Spirogyra bi-cultures, 86 % (616 S.E.) in Oedogonium-Cladophora bi-cultures and 82 % (618 S.E.) in polycultures. The high productivity, bioenergy potential an
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Removing Constraints on the Biomass Production of Freshwater Macroalgae by Manipulating Water Exchange to Manage Nutrient Flux
2016Co-Authors: Andrew J Cole, Rocky De Nys, Nicholas A PaulAbstract:Freshwater macroalgae represent a largely overlooked group of phototrophic organisms that could play an important role within an industrial ecology context in both utilising waste nutrients and water and supplying biomass for animal feeds and renewable chemicals and fuels. This study used water from the intensive aquaculture of freshwater fish (Barramundi) to examine how the biomass production rate and protein content of the freshwater macroalga Oedogonium responds to increasing the flux of nutrients and carbon, by either increasing water exchange rates or through the addition of supplementary nitrogen and CO2. Biomass production rates were highest at low flow rates (0.1–1 vol.day 21) using raw pond water. The addition of CO2 to cultures increased biomass production rates by between 2 and 25 % with this effect strongest at low water exchange rates. Paradoxically, the addition of nitrogen to cultures decreased productivity, especially at low water exchange rates. The optimal culture of Oedogonium occurred at flow rates of between 0.5–1 vol.day21, where uptake rates peaked at 1.09 g.m22.day21 for nitrogen and 0.13 g.m22.day21 for phosphorous. At these flow rates Oedogonium biomass had uptake efficiencies of 75.2 % for nitrogen and 22.1 % for phosphorous. In this study a nitrogen flux of 1.45 g.m22.day21 and a phosphorous flux of 0.6 g.m22.day21 was the minimum required to maintain the growth of Oedogonium at 16–17 g DW.m22.day21 and a crude protein content of 25%. A simple model of minimum inputs shows tha
Rebecca J. Lawton - One of the best experts on this subject based on the ideXlab platform.
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Selecting Reliable and Robust Freshwater Macroalgae for Biomass Applications
2016Co-Authors: Rebecca J. Lawton, Rocky De Nys, Nicholas A PaulAbstract:Intensive cultivation of freshwater macroalgae is likely to increase with the development of an algal biofuels industry and algal bioremediation. However, target freshwater macroalgae species suitable for large-scale intensive cultivation have not yet been identified. Therefore, as a first step to identifying target species, we compared the productivity, growth and biochemical composition of three species representative of key freshwater macroalgae genera across a range of cultivation conditions. We then selected a primary target species and assessed its competitive ability against other species over a range of stocking densities. Oedogonium had the highest productivity (8.0 g ash free dry weight m22 day21), lowest ash content (3–8%), lowest water content (fresh weigh: dry weight ratio of 3.4), highest carbon content (45%) and highest bioenergy potential (higher heating value 20 MJ/kg) compared to Cladophora and Spirogyra. The higher productivity of Oedogonium relative to Cladophora and Spirogyra was consistent when algae were cultured with and without the addition of CO2 across three aeration treatments. Therefore, Oedogonium was selected as our primary target species. The competitive ability of Oedogonium was assessed by growing it in bi-cultures and polycultures with Cladophora and Spirogyra over a range of stocking densities. Cultures were initially stocked with equal proportions of each species, but after three weeks of growth the proportion of Oedogonium had increased to at least 96 % (67 S.E.) in Oedogonium-Spirogyra bi-cultures, 86 % (616 S.E.) in Oedogonium-Cladophora bi-cultures and 82 % (618 S.E.) in polycultures. The high productivity, bioenergy potential an
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The effect of salinity on the biomass productivity, protein and lipid composition of a freshwater macroalga
Algal Research-Biomass Biofuels and Bioproducts, 2015Co-Authors: Rebecca J. Lawton, Marie Magnusson, Nicholas A PaulAbstract:Abstract A critical knowledge gap in the production of macroalgae for protein (animal feed) and lipid (bioenergy) is the ability of target species to grow in saline groundwater and thereby avoid competition with traditional crops. We assessed the effect of increased salinity (0.11 ppt–3 ppt) on the growth of 5 strains of the freshwater macroalga Oedogonium in laboratory cultures and subsequently on the productivity and biochemical composition in outdoor cultures under ambient conditions. Growth and biomass productivity decreased with increasing salinity in both experiments across all strains. However, in contrast to biomass productivity, protein content increased with increasing salinity and consequently, protein productivity (0.2–0.6 g DW m − 2 day − 1 ) did not decrease markedly as salinity increased. Salinity had inconsistent effects on the lipid content among the strains, with the content of 2 strains increasing 3 to 4-fold under the 3 ppt treatment compared to 0.11 ppt. However, lipid productivity decreased with increasing salinity for 4 of the 5 strains. Similarly, biomass energy values increased with increasing salinity across all strains while bioenergy productivity decreased. These findings demonstrate that Oedogonium grown in salinities of up to 3 ppt maintains its productivity as a source of protein, potentially for animal feed, but not for bioenergy.
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Isolation and identification of Oedogonium species and strains for biomass applications.
PloS one, 2014Co-Authors: Rebecca J. Lawton, Rocky De Nys, Stephen Skinner, Nicholas A PaulAbstract:Freshwater macroalgae from the genus Oedogonium have recently been targeted for biomass applications; however, strains of Oedogonium for domestication have not yet been identified. Therefore, the objective of this study was to compare the performance of isolates of Oedogonium collected from multiple geographic locations under varying environmental conditions. We collected and identified wild-type isolates of Oedogonium from three geographic locations in Eastern Australia, then measured the growth of these isolates under a range of temperature treatments corresponding to ambient conditions in each geographic location. Our sampling identified 11 isolates of Oedogonium that could be successfully maintained under culture conditions. It was not possible to identify most isolates to species level using DNA barcoding techniques or taxonomic keys. However, there were considerable genetic and morphological differences between isolates, strongly supporting each being an identifiable species. Specific growth rates of species were high (>26% day−1) under 7 of the 9 temperature treatments (average tested temperature range: 20.9–27.7°C). However, the variable growth rates of species under lower temperature treatments demonstrated that some were better able to tolerate lower temperatures. There was evidence for local adaptation under lower temperature treatments (winter conditions), but not under higher temperature treatments (summer conditions). The high growth rates we recorded across multiple temperature treatments for the majority of species confirm the suitability of this diverse genus for biomass applications and the domestication of Oedogonium.
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Selecting Reliable and Robust Freshwater Macroalgae for Biomass Applications
PloS one, 2013Co-Authors: Rebecca J. Lawton, Rocky De Nys, Nicholas A PaulAbstract:Intensive cultivation of freshwater macroalgae is likely to increase with the development of an algal biofuels industry and algal bioremediation. However, target freshwater macroalgae species suitable for large-scale intensive cultivation have not yet been identified. Therefore, as a first step to identifying target species, we compared the productivity, growth and biochemical composition of three species representative of key freshwater macroalgae genera across a range of cultivation conditions. We then selected a primary target species and assessed its competitive ability against other species over a range of stocking densities. Oedogonium had the highest productivity (8.0 g ash free dry weight m−2 day−1), lowest ash content (3–8%), lowest water content (fresh weigh: dry weight ratio of 3.4), highest carbon content (45%) and highest bioenergy potential (higher heating value 20 MJ/kg) compared to Cladophora and Spirogyra. The higher productivity of Oedogonium relative to Cladophora and Spirogyra was consistent when algae were cultured with and without the addition of CO2 across three aeration treatments. Therefore, Oedogonium was selected as our primary target species. The competitive ability of Oedogonium was assessed by growing it in bi-cultures and polycultures with Cladophora and Spirogyra over a range of stocking densities. Cultures were initially stocked with equal proportions of each species, but after three weeks of growth the proportion of Oedogonium had increased to at least 96% (±7 S.E.) in Oedogonium-Spirogyra bi-cultures, 86% (±16 S.E.) in Oedogonium-Cladophora bi-cultures and 82% (±18 S.E.) in polycultures. The high productivity, bioenergy potential and competitive dominance of Oedogonium make this species an ideal freshwater macroalgal target for large-scale production and a valuable biomass source for bioenergy applications. These results demonstrate that freshwater macroalgae are thus far an under-utilised feedstock with much potential for biomass applications.
Xavier Lazzaro - One of the best experts on this subject based on the ideXlab platform.
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Association of a Specific Algal Group with Methylmercury Accumulation in Periphyton of a Tropical High-Altitude Andean Lake
Archives of Environmental Contamination and Toxicology, 2017Co-Authors: William G. Lanza, Darío Achá, David Point, Jeremy Masbou, Lucia Alanoca, David Amouroux, Xavier LazzaroAbstract:Periphyton relevance for methylmercury (MeHg) production and accumulation are now well known in aquatic ecosystems. Sulfate-reducing bacteria and other microbial groups were identified as the main MeHg producers, but the effect of periphyton algae on the accumulation and transfer of MeHg to the food web remains little studied. Here we investigated the role of specific groups of algae on MeHg accumulation in the periphyton of Schoenoplectus californicus ssp. (Totora) and Myriophyllum sp. in Uru Uru, a tropical high-altitude Bolivian lake with substantial fishing and mining activities accruing around it. MeHg concentrations were most strongly related to the cell abundance of the Chlorophyte genus Oedogonium ( r ^2 = 0.783, p = 0.0126) and to no other specific genus despite the presence of other 34 genera identified. MeHg was also related to total chlorophyll-a (total algae) ( r ^2 = 0.675, p = 0.0459), but relations were more significant with chlorophyte cell numbers, chlorophyll-b (chlorophytes), and chlorophyll-c (diatoms and dinoflagellates) ( r ^2 = 0.72, p = 0.028, r ^2 = 0.744, p = 0.0214, and r ^2 = 0.766, p = 0.0161 respectively). However, Oedogonium explains most variability of chlorophytes and chlorophyll-c ( r ^2 = 0.856, p =
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Association of a Specific Algal Group with Methylmercury Accumulation in Periphyton of a Tropical High-Altitude Andean Lake
Archives of Environmental Contamination and Toxicology, 2017Co-Authors: William G. Lanza, Darío Achá, David Point, Jeremy Masbou, Lucia Alanoca, David Amouroux, Xavier LazzaroAbstract:Periphyton relevance for methylmercury (MeHg) production and accumulation are now well known in aquatic ecosystems. Sulfate-reducing bacteria and other microbial groups were identified as the main MeHg producers, but the effect of periphyton algae on the accumulation and transfer of MeHg to the food web remains little studied. Here we investigated the role of specific groups of algae on MeHg accumulation in the periphyton of Schoenoplectus californicus ssp. (Totora) and Myriophyllum sp. in Uru Uru, a tropical high-altitude Bolivian lake with substantial fishing and mining activities accruing around it. MeHg concentrations were most strongly related to the cell abundance of the Chlorophyte genus Oedogonium (r2 = 0.783, p = 0.0126) and to no other specific genus despite the presence of other 34 genera identified. MeHg was also related to total chlorophyll-a (total algae) (r2 = 0.675, p = 0.0459), but relations were more significant with chlorophyte cell numbers, chlorophyll-b (chlorophytes), and chlorophyll-c (diatoms and dinoflagellates) (r2 = 0.72, p = 0.028, r2 = 0.744, p = 0.0214, and r2 = 0.766, p = 0.0161 respectively). However, Oedogonium explains most variability of chlorophytes and chlorophyll-c (r2 = 0.856, p = < 0.001 and r2 = 0.619, p = 0.002, respectively), suggesting it is the most influential group for MeHg accumulation and periphyton algae composition at this particular location and given time.
Marie Magnusson - One of the best experts on this subject based on the ideXlab platform.
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dose response effects of asparagopsis taxiformis and Oedogonium sp on in vitro fermentation and methane production
Journal of Applied Phycology, 2016Co-Authors: Lorenna Machado, Nicholas A Paul, Marie Magnusson, Nigel William TomkinsAbstract:This study aimed to identify the optimal doses of the macroalgae Asparagopsis taxiformis and Oedogonium sp., individually and in combination, which would decrease the in vitro production of methane while minimizing adverse effects on fermentation, using rumen inoculant from Bos indicus steers. The dose-response experiment evaluated ten doses of Asparagopsis [ranging from 0 to 16.7 % of the organic matter (OM) incubated] and seven doses of Oedogonium (ranging from 0 to 100 % OM) using Rhodes grass hay as a basal substrate. Asparagopsis was highly effective in decreasing the production of methane with a reduction of 99 % at doses as low as 2 % OM basis. However, a dose of 2 % OM also decreased the production of volatile fatty acids (VFA). Oedogonium was less effective with doses ≥50 % OM significantly decreasing the production of methane. A combination of Asparagopsis (2 % OM) and Oedogonium (25 and 50 % OM) continued to suppress the production of methane, independent of the inclusion rate of Oedogonium. The effectiveness of Asparagopsis demonstrates its potential for the mitigation of methane emissions from ruminants at inclusion rates of ≤2 % OM. Oedogonium is a potential feed supplement due to its nutritional value, but supplements ≤25 % OM are recommended to avoid adverse effects on apparent in vitro fermentation.
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The treatment of municipal wastewater by the macroalga Oedogonium sp. and its potential for the production of biocrude
Algal Research, 2016Co-Authors: Nicolas Neveux, Marie Magnusson, R. De Nys, Leonardo Mata, Anna Whelan, Nicholas A PaulAbstract:Abstract Municipal wastewater represents a significant yet under-utilised resource for the commercial production of algae. However, in order to realise this potential, two constraints must first be addressed — the treatment of wastewater to levels comparable with existing technologies and the reliable production of monocultures as the basis for commercial products. In this study, three municipal wastewater sources were investigated at various water exchange rates for the cultivation of the filamentous freshwater macroalga Oedogonium sp., demonstrating that the delivery of nutrients through primary effluent at a low exchange rate of 5% volume per day supported high biomass productivity. A continuous high-density culture of Oedogonium (0.25–1.5 g/L fresh weight) in a pilot-scale pond system yielded biomass productivities of 7–10 g/m 2 /d dry weight and nutrient removal rates of 0.50 g nitrogen/m 2 /d and 0.11 g phosphorus/m 2 /d without the addition of CO 2 . Nitrogen, phosphorus and chemical oxygen demand were reduced by 62%, 75% and 57% respectively in the treated water. The concentration of microbes was reduced by 99% and some metal contaminants that can impede the reuse of treated water were also reduced by 99%. The biomass produced had a relatively consistent biochemical composition that would yield 26–27% of the dry weight as biocrude oil through hydrothermal liquefaction. The results demonstrate that monocultures of Oedogonium sp. can be used to treat multiple components of municipal wastewater and simultaneously deliver biomass that can be conveniently harvested and converted to biocrude for the production of drop-in fuels.
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The effect of salinity on the biomass productivity, protein and lipid composition of a freshwater macroalga
Algal Research-Biomass Biofuels and Bioproducts, 2015Co-Authors: Rebecca J. Lawton, Marie Magnusson, Nicholas A PaulAbstract:Abstract A critical knowledge gap in the production of macroalgae for protein (animal feed) and lipid (bioenergy) is the ability of target species to grow in saline groundwater and thereby avoid competition with traditional crops. We assessed the effect of increased salinity (0.11 ppt–3 ppt) on the growth of 5 strains of the freshwater macroalga Oedogonium in laboratory cultures and subsequently on the productivity and biochemical composition in outdoor cultures under ambient conditions. Growth and biomass productivity decreased with increasing salinity in both experiments across all strains. However, in contrast to biomass productivity, protein content increased with increasing salinity and consequently, protein productivity (0.2–0.6 g DW m − 2 day − 1 ) did not decrease markedly as salinity increased. Salinity had inconsistent effects on the lipid content among the strains, with the content of 2 strains increasing 3 to 4-fold under the 3 ppt treatment compared to 0.11 ppt. However, lipid productivity decreased with increasing salinity for 4 of the 5 strains. Similarly, biomass energy values increased with increasing salinity across all strains while bioenergy productivity decreased. These findings demonstrate that Oedogonium grown in salinities of up to 3 ppt maintains its productivity as a source of protein, potentially for animal feed, but not for bioenergy.
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biocrude yield and productivity from the hydrothermal liquefaction of marine and freshwater green macroalgae
Bioresource Technology, 2014Co-Authors: Nicolas Neveux, Nicholas A Paul, Marie Magnusson, Alexander K L Yuen, Christopher Jazrawi, Brian S Haynes, A F Masters, Alejandro Montoya, Thomas MaschmeyerAbstract:Six species of marine and freshwater green macroalgae were cultivated in outdoor tanks and subsequently converted to biocrude through hydrothermal liquefaction (HTL) in a batch reactor. The influence of the biochemical composition of biomass on biocrude yield and composition was assessed. The freshwater macroalgae Oedogonium afforded the highest biocrude yield of all six species at 26.2%, dry weight (dw). Derbesia (19.7% dw) produced the highest biocrude yield for the marine species followed by Ulva (18.7% dw). In contrast to significantly different yields across species, the biocrudes elemental profiles were remarkably similar with higher heating values of 33–34 MJ kg−1. Biocrude productivity was highest for marine Derbesia (2.4 g m−2 d−1) and Ulva (2.1 g m−2 d−1), and for freshwater Oedogonium (1.3 g m−2 d−1). These species were therefore identified as suitable feedstocks for scale-up and further HTL studies based on biocrude productivity, as a function of biomass productivity and the yield of biomass conversion to biocrude.
