• Energy Research

A 12-week feeding trial examined the dietary impact of replacing fishmeal (FM) with algal biomass (AB) derived from Pavlova sp. strain CCMP459 (Pav459) in Atlantic salmon diets. Three distinct diets were formulated: a control diet featuring 20% FM and 7% fish oil (FO), an experimental diet incorporating a 50:50 blend of FM and AB Pav459 and reduced FO (10% FM; 4.5% FO; 10% AB), and a second experimental diet with full replacement of FM with AB Pav459 and further reduction in FO (1.75% FO; 20% AB). Replacing FM with AB Pav459 showed no significant effects on the growth performance of Atlantic salmon. Fish across all diets exhibited growth exceeding 200% from their initial weight. Analysis of total lipid content after the 12-week trial revealed no significant differences among the diets. However, individual proportions of omega-3 (ω3) and omega-6 (ω6) fatty acids varied. Fatty acid profiling in muscle and liver tissues showed distinct compositions reflective of dietary treatments. Linoleic acid (LA) and α-linolenic acid (ALA) exhibited higher proportions in total fatty acids than in membrane lipids. Docosahexaenoic acid (DHA) emerged as the predominant fatty acid in the membranes of both liver and muscle tissues. Furthermore, an analysis of sterol composition in Pavlova and salmon muscle tissue showed the presence of important sterols, including conventionally animal-associated cholesterol. This emphasizes the suitability of microorganisms, such as Pav459, for synthesizing diverse nutrients. Stable isotope analysis demonstrated direct incorporation of eicosapentaenoic acid (EPA) and DHA from diets into salmon tissues. Notably, minimal biosynthesis from the precursor ALA was observed, reaffirming the utility of Pav459-derived fatty acids. The EPA+DHA proportions in the fillet consistently met daily human consumption requirements across all dietary conditions, supporting the use of Pav459 algal biomass as an alternative to FM.

A 12-week feeding trial examined the dietary impact of replacing fishmeal (FM) with algal biomass (AB) derived from Pavlova sp. strain CCMP459 (Pav459) in Atlantic salmon diets. Three distinct diets were formulated: a control diet featuring 20% FM and 7% fish oil (FO), an experimental diet incorporating a 50:50 blend of FM and AB Pav459 and reduced FO (10% FM; 4.5% FO; 10% AB), and a second experimental diet with full replacement of FM with AB Pav459 and further reduction in FO (1.75% FO; 20% AB). Replacing FM with AB Pav459 showed no significant effects on the growth performance of Atlantic salmon. Fish across all diets exhibited growth exceeding 200% from their initial weight. Analysis of total lipid content after the 12-week trial revealed no significant differences among the diets. However, individual proportions of omega-3 (ω3) and omega-6 (ω6) fatty acids varied. Fatty acid profiling in muscle and liver tissues showed distinct compositions reflective of dietary treatments. Linoleic acid (LA) and α-linolenic acid (ALA) exhibited higher proportions in total fatty acids than in membrane lipids. Docosahexaenoic acid (DHA) emerged as the predominant fatty acid in the membranes of both liver and muscle tissues. Furthermore, an analysis of sterol composition in Pavlova and salmon muscle tissue showed the presence of important sterols, including conventionally animal-associated cholesterol. This emphasizes the suitability of microorganisms, such as Pav459, for synthesizing diverse nutrients. Stable isotope analysis demonstrated direct incorporation of eicosapentaenoic acid (EPA) and DHA from diets into salmon tissues. Notably, minimal biosynthesis from the precursor ALA was observed, reaffirming the utility of Pav459-derived fatty acids. The EPA+DHA proportions in the fillet consistently met daily human consumption requirements across all dietary conditions, supporting the use of Pav459 algal biomass as an alternative to FM.

Abstract Production of microalgae is a potential technology for capturing and recycling carbon dioxide from cement kiln emissions. In this study, a process of selecting a suitable strain that would effectively utilize carbon dioxide and generate biomass was investigated. A down-selection screening method was applied to 28 strains isolated from the area surrounding a commercial cement plant. In laboratory-scale (1 L) continuous-mode chemostats, observed productivity was > 0.9 g L−1 d−1 for most strains studied. Chlorella sorokiniana (strain SMC-14M) appeared to be the most tolerant to cement kiln gas emissions in situ, delivered under control of a pH-stat system, and was down-selected to further investigate growth and biomass production at large-scale (1000 L) cultivation. Results demonstrated little variability in lipid, crude protein, and carbohydrate composition throughout growth between kiln-gas grown algal biomass and biomass produced with laboratory grade CO2. The growth rate at which the maximum quantity of CO2 from the emissions is recycled also produced the maximum amount of the targeted biomass components to increase commercial value of the biomass. An accumulation of some heavy metals throughout its growth demonstrates the necessity to monitor the biomass cultivated with industrial flue gases and to carefully consider the potential applications for this biomass; despite its other attractive nutritional properties. Key points • Studied high biomass producing algal strains grown on CO2from cement flue gas. • Chlorella sorokiniana SMC-14M grew well at large scale, in situ on cement flue gas. • Demonstrated the resulting commercial potential of the cultured algal biomass.

Abstract Production of microalgae is a potential technology for capturing and recycling carbon dioxide from cement kiln emissions. In this study, a process of selecting a suitable strain that would effectively utilize carbon dioxide and generate biomass was investigated. A down-selection screening method was applied to 28 strains isolated from the area surrounding a commercial cement plant. In laboratory-scale (1 L) continuous-mode chemostats, observed productivity was > 0.9 g L−1 d−1 for most strains studied. Chlorella sorokiniana (strain SMC-14M) appeared to be the most tolerant to cement kiln gas emissions in situ, delivered under control of a pH-stat system, and was down-selected to further investigate growth and biomass production at large-scale (1000 L) cultivation. Results demonstrated little variability in lipid, crude protein, and carbohydrate composition throughout growth between kiln-gas grown algal biomass and biomass produced with laboratory grade CO2. The growth rate at which the maximum quantity of CO2 from the emissions is recycled also produced the maximum amount of the targeted biomass components to increase commercial value of the biomass. An accumulation of some heavy metals throughout its growth demonstrates the necessity to monitor the biomass cultivated with industrial flue gases and to carefully consider the potential applications for this biomass; despite its other attractive nutritional properties. Key points • Studied high biomass producing algal strains grown on CO2from cement flue gas. • Chlorella sorokiniana SMC-14M grew well at large scale, in situ on cement flue gas. • Demonstrated the resulting commercial potential of the cultured algal biomass.

AbstractThe aims of this review are to describe the role of ‘blue‐food production’ (animals, plants and algae harvested from freshwater and marine environments) within a circular bioeconomy, discuss how such a framework can help the sustainability and resilience of aquaculture and to summarise key examples of novel nutrient sources that are emerging in the field of fed‐aquaculture species. Aquaculture now provides >50% of the global seafood supply, a share that is expected to increase to at least 60% within the next decade. Aquaculture is an important tool for reducing resource consumption in global protein production and increasing resilience to climate change and other global disruptions (i.e. pandemics, geo‐political instability). Importantly, blue foods also provide essential nutrition for a growing human population. Blue foods are helping to help the global goal of ‘zero hunger’ (United Nation's Sustainable Development Goal 2) while reducing the dependency on finite natural resources but further refinement and new solutions are needed to make the industry more ‘circular’ and sustainable, particularly with respect to sourcing raw materials for aquafeeds. This review describes the feed resources that are available or may be created within a circular bioeconomy framework, their role within the framework and in aquaculture and ultimately, how these resources contribute to de‐risking and establishing a resilient aquaculture production chain.

AbstractThe aims of this review are to describe the role of ‘blue‐food production’ (animals, plants and algae harvested from freshwater and marine environments) within a circular bioeconomy, discuss how such a framework can help the sustainability and resilience of aquaculture and to summarise key examples of novel nutrient sources that are emerging in the field of fed‐aquaculture species. Aquaculture now provides >50% of the global seafood supply, a share that is expected to increase to at least 60% within the next decade. Aquaculture is an important tool for reducing resource consumption in global protein production and increasing resilience to climate change and other global disruptions (i.e. pandemics, geo‐political instability). Importantly, blue foods also provide essential nutrition for a growing human population. Blue foods are helping to help the global goal of ‘zero hunger’ (United Nation's Sustainable Development Goal 2) while reducing the dependency on finite natural resources but further refinement and new solutions are needed to make the industry more ‘circular’ and sustainable, particularly with respect to sourcing raw materials for aquafeeds. This review describes the feed resources that are available or may be created within a circular bioeconomy framework, their role within the framework and in aquaculture and ultimately, how these resources contribute to de‐risking and establishing a resilient aquaculture production chain.

AbstractBACKGROUNDMicroalgae cultivation in wastewaters is a potential remediation technology for converting residual nutrients into valuable biomass for biofuels, fertilizers, animal and aquaculture feeds, and bio‐based chemicals. The objective of this study was to determine the potential for microalgae phycoremediation of aquaculture and agriculture wastewaters for sustainable production of nutrient‐rich algal biomass.RESULTSThirty‐seven aquaculture and agriculture wastewaters were evaluated as growth media for two freshwater, chlorophytic microalgae strains (Chlorella sorokiniana SMC14M and Scenedesmus sp. AMDD). Although nutrient levels and physicochemical parameters of the wastewaters varied widely, phycoremediation efficiency of nitrogen and phosphorous was high (> 70%) for a large majority of them, with both microalgae strains. Photobioreactor cultivation (300 L) of C. sorokiniana grown on finfish aquaculture wastewater (CA2) and standard growth medium (SGM) exhibited similar biomass production levels and nutritional compositions of moisture (4.9–5.0%), ash (5.9–6.1%), nitrogen (8.6–8.8%), protein (41.0–42.1%), lipid (8.6–8.8%), carbohydrate (38.3–39.3%) and gross energy (22.2–22.3 MJ⋅kg−1) with highly similar fatty acid and amino acid profiles.CONCLUSIONSThis study demonstrates that the use of freshwater microalgae to remediate various aquaculture and agriculture wastewaters, while producing valuable nutrient‐rich biomass, is feasible. We have found that a particular finfish aquaculture wastewater (CA2) contains all of the nutrients required for rapid microalgae growth, avoiding the need for expensive commercial fertilizers. The biochemical composition of C. sorokiniana grown on CA2 aquaculture wastewater has good potential for use as a nutrient‐rich ingredient for animal and aquaculture feeds, fertilizers products, biofuels and other applications, resulting in remediated water that could be reused. © 2023 National Research Council Canada. Reproduced with the permission of the Minister of Innovation, Science, and Economic Development.

AbstractBACKGROUNDMicroalgae cultivation in wastewaters is a potential remediation technology for converting residual nutrients into valuable biomass for biofuels, fertilizers, animal and aquaculture feeds, and bio‐based chemicals. The objective of this study was to determine the potential for microalgae phycoremediation of aquaculture and agriculture wastewaters for sustainable production of nutrient‐rich algal biomass.RESULTSThirty‐seven aquaculture and agriculture wastewaters were evaluated as growth media for two freshwater, chlorophytic microalgae strains (Chlorella sorokiniana SMC14M and Scenedesmus sp. AMDD). Although nutrient levels and physicochemical parameters of the wastewaters varied widely, phycoremediation efficiency of nitrogen and phosphorous was high (> 70%) for a large majority of them, with both microalgae strains. Photobioreactor cultivation (300 L) of C. sorokiniana grown on finfish aquaculture wastewater (CA2) and standard growth medium (SGM) exhibited similar biomass production levels and nutritional compositions of moisture (4.9–5.0%), ash (5.9–6.1%), nitrogen (8.6–8.8%), protein (41.0–42.1%), lipid (8.6–8.8%), carbohydrate (38.3–39.3%) and gross energy (22.2–22.3 MJ⋅kg−1) with highly similar fatty acid and amino acid profiles.CONCLUSIONSThis study demonstrates that the use of freshwater microalgae to remediate various aquaculture and agriculture wastewaters, while producing valuable nutrient‐rich biomass, is feasible. We have found that a particular finfish aquaculture wastewater (CA2) contains all of the nutrients required for rapid microalgae growth, avoiding the need for expensive commercial fertilizers. The biochemical composition of C. sorokiniana grown on CA2 aquaculture wastewater has good potential for use as a nutrient‐rich ingredient for animal and aquaculture feeds, fertilizers products, biofuels and other applications, resulting in remediated water that could be reused. © 2023 National Research Council Canada. Reproduced with the permission of the Minister of Innovation, Science, and Economic Development.