Environmental Impacts of Large-Scale Spirulina (Arthrospira platensis) Production in Hellisheidi Geothermal Park Iceland: Life Cycle Assessment

Partial substitution of soybean meal with microalgae meal (Arthrospira spp. - Spirulina) in grower and finisher diets for broiler chickens: implications on performance parameters, footpad dermatitis occurrence, breast meat quality traits, amino acid digestibility and plasma metabolomics profile

This trial was conducted to evaluate the effects of replacing soybean meal with microalgae meal (MM; Arthrospira spp.) during grower and finisher phases on productive performance, footpad dermatitis (FPD) occurrence, breast meat quality, amino acid digestibility and plasma metabolomics profile of broiler chickens. One thousand day-old Ross 308 male chicks were divided into 5 experimental groups (8 replicates, 25 birds/each): CON, fed a commercial soybean-based diet throughout the trial (0-41 d); F3 and F6, fed the CON diet up to 28 d of age and then a finisher diet (29-41 d) with either 30 or 60 g MM/kg, respectively; and GF3 and GF6, receiving CON diet until 14 d and then diets containing 30 or 60 g MM/kg from 15 to 41 d, respectively. All diets were iso-energetic and with a similar amino acid profile. Growth performances were recorded on a pen basis at the end of each feeding phase and apparent ileal amino acid digestibility was determined at 41 d. Footpad dermatitis occurrence was assessed on all processed birds, while breast and plasma samples were collected for meat quality and metabolomics analysis (proton nuclear magnetic resonance - 1H-NMR). At 41 d, CON group showed higher body weight than F6 and GF6 ones (2,541 vs. 2,412 vs. 2,384 g, respectively; P < 0.05). Overall, GF6 group exhibited the highest feed conversion ratio, while F3 did not present significant differences compared to CON (1.785 vs. 1.810 vs. 1.934 g feed/g gain, respectively for CON, F3 and GF6; P < 0.01). The occurrence and the risk of developing FPD were similar among groups. MM administration increased breast meat yellowness and reduced amino acid digestibility (P < 0.001). The 1H-NMR analysis revealed variations in the levels of some circulating metabolites, including histidine, arginine and creatine, which play important metabolic roles. Overall, these findings can contribute to expand the knowledge about the use of Arthrospira spp. as protein source in broiler diets.

Investigation on the enhancement of crack restoration properties in cement incorporated with Arthrospira platensis cultured in modified medium

This study investigated the potential use of microalgae as partial cement replacement to heal cracks in cement mortar. Microbially induced calcite (CaCO3) precipitation (MICP) from Arthrospira platensis (A. platensis) (UMACC162) was utilised for crack-healing applications. Microalgae was cultivated in Kosaric Media (KM) together with filtered cement water (FCW), and used as a cement replacement material. The microalgal species was further evaluated for its capacity and adaptability towards large-scale culturing. The results showed that A. platensis could adapt and survive in cement water solution and cement mortar, suggesting the potential for self-healing in cement mortar. Further, the cultured species grown in both conditions (KM and KM & FCW) were harvested and incorporated into the cement mortar as a partial cement replacement material at different levels of 5%, 10%, 20%, and 30% of cement weight. The cement mortars partially replaced with microalgae were cured in water for 28 days. Pre-cracks were induced in the cured mortar with the 75% of their ultimate load. It took just 14 days for the microalgae-incorporated mortar to heal the cracks. The specimens with microalgae cultured in FCW showed a better performance and recovered 59% of their strength, with a maximum healed crack width of 0.7 mm. In terms of water tightness and porosity, they are comparable to the control mortar. The compressive strength measurements indicated the formation of calcite aggregate (crystal) that sealed the surface cracks, which was confirmed by a microstructural analysis. The results also demonstrate that the incorporation of microalgae into cement produced a self-healing effect, providing a new direction for crack healing. Additionally, the investigation indicated that replacing cement with microalgae reduced CO2 emissions by as much as 30%, with a substitution of 30% of microalgae. Exploring microalgae as a cement replacement could reduce carbon emissions and improve the state of the environment.

Scenario analysis of the socioeconomic impacts of achieving zero-carbon energy by 2030

This study uses scenario analysis to assess the socioeconomic impacts of achieving zero-carbon energy by 2030. Three scenarios are developed: 1) business as usual; 2) accelerated deployment of renewable energy and electric vehicles; and 3) scenario 2 plus comprehensive energy efficiency improvements. Quantitative models are used to evaluate the impacts on employment, productivity, consumer costs, inequality and energy security under each scenario. The results show that scenario 3, with the most ambitious decarbonization and efficiency measures, can generate the most jobs (2.1 million more than business as usual) and the lowest consumer costs (12% reduction). However, it may also lead to a small productivity loss (1.2% lower than business as usual) due to higher costs of new technologies. Income and health inequality are projected to decrease across all scenarios due to improved energy access and reduced fuel poverty. Energy security is expected to improve significantly in scenarios 2 and 3 due to reduced oil dependence. This study provides an analytical framework to assess the integrated socioeconomic impacts of zero-carbon transitions under uncertainty. The scenarios and findings can inform policymaking by highlighting the opportunities and challenges around the low-carbon transition, enabling decision makers to maximize benefits and minimize negative consequences.

Overview and Challenges of Large-Scale Cultivation of Photosynthetic Microalgae and Cyanobacteria

Microalgae and cyanobacteria are diverse groups of organisms with great potential to benefit societies across the world. These organisms are currently used in food, feed, pharmaceutical and cosmetic industries. In addition, a variety of novel compounds are being isolated. Commercial production of photosynthetic microalgae and cyanobacteria requires cultivation on a large scale with high throughput. However, scaling up production from lab-based systems to large-scale systems is a complex and potentially costly endeavor. In this review, we summarise all aspects of large-scale cultivation, including aims of cultivation, species selection, types of cultivation (ponds, photobioreactors, and biofilms), water and nutrient sources, temperature, light and mixing, monitoring, contamination, harvesting strategies, and potential environmental risks. Importantly, we also present practical recommendations and discuss challenges of profitable large-scale systems associated with economical design, effective operation and maintenance, automation, and shortage of experienced phycologists.

Microalgae-Sustainable Source for Alternative Proteins and Functional Ingredients Promoting Gut and Liver Health

Dietary proteins derived from animal sources, although containing well-balanced profiles of essential amino acids, have considerable environmental and adverse health effects associated with the intake of some animal protein-based products. Consuming foods based on animal proteins carries a higher risk of developing non-communicable diseases such as cancer, heart disease, non-alcoholic fatty liver disease (NAFLD), and inflammatory bowel disease (IBD). Moreover, dietary protein consumption is increasing due to population growth, posing a supply challenge. There is, therefore, growing interest in discovering novel alternative protein sources. In this context, microalgae have been recognized as strategic crops that can provide a sustainable source of protein. Compared to conventional high-protein crops, using microalgal biomass for protein production presents several advantages in food and feed in terms of productivity, sustainability, and nutritional value. Moreover, microalgae positively impact the environment by not exploiting land or causing water pollution. Many studies have revealed the potential of microalgae as an alternative protein source with the added value of positive effects on human health due to their anti-inflammatory, antioxidant, and anti-cancer properties. The main emphasis of this review is on the potential health-promoting applications of microalgae-based proteins, peptides, and bioactive substances for IBD and NAFLD.

The Potential Role of Iceland in Northern Europe's Protein Self-Sufficiency: Feasibility Study of Large-Scale Production of Spirulina in a Novel Energy-Food System

Europe is dependent on protein-rich crop imports to meet domestic food demand. This has moved the topic of sustainable protein self-sufficiency up the policy agenda. The current study assesses the feasibility of protein self-sufficiency in Iceland, and its capacity to meet Northern Europe's demand, based on industrial-scale cultivation of Spirulina in novel production units. Production units currently operating in Iceland, and laboratory-derived nutritional profile for the Spirulina cultivated, provide the basis for a theoretical protein self-sufficiency model. Integrating installed and potentially installed energy generation data, the model elaborates six production scale-up scenarios. Annual biomass produced is compared with recommended dietary allowance figures for protein and essential amino acids to determine whether Northern Europe's population demands can be met in 2030. Results show that Iceland could be protein self-sufficient under the most conservative scenario, with 20,925 tonnes of Spirulina produced using 15% of currently installed capacity. In a greater allocation of energy capacity used by heavy industry, Iceland could additionally meet the needs of Lithuania, or Latvia, Estonia, Jersey, Isle of Man, Guernsey, and Faroe Islands. Under the most ambitious scenario utilizing planned energy projects, Iceland could support itself plus Denmark, or Finland, or Norway, or Ireland with up to 242,366 tonnes of biomass. On a protein-per-protein basis, each kilogram of Spirulina consumed instead of beef could save 0.315 tonnes CO₂-eq. Under the most ambitious scenario, this yields annual savings of 75.1 million tonnes CO₂-eq or 7.3% of quarterly European greenhouse gas emissions. Finally, practicalities of production scale-up are discussed.