The case study focuses on an organic spirulina production facility in Southern Italy, operating under certified organic standards. The facility integrates circular economy principles through a closed-loop system in which wastewater from pasta-making processes is purified via an oxidation system and reverse osmosis and then reused as a nutrient source for spirulina cultivation. Water consumption is managed through 1,300 m³/year sourced from treated pasta-process wastewater and 1,608 m³/year supplied by Acquedotto Pugliese, totaling 2,908 m³/year. The analyzed operating period corresponds to the facility’s seasonal production window (April–November 2023) carried out on a total area of 3,040 m², using two raceway ponds under greenhouse cover (1,440 m² established in 2021 and 1,600 m² established in 2023). Harvesting occurs every 1–3 days depending on culture density, followed by rapid quality checks and drying in an oven, producing an annual yield of approximately 3 tons of dried spirulina (about 1.5 tons per greenhouse). From a process perspective, production follows a greenhouse-compatible microalgae configuration based on open raceway pond cultivation requiring continuous mixing and circulation, followed by downstream processing where drying is necessary to stabilize biomass for food use. Because mixing/circulation and drying are electricity-intensive, energy demand is both an environmental hotspot and a key operational consideration addressed explicitly in the environmental discussion and limitations. The life-cycle inventory reflects the facility’s organic and circular inputs, including treated wastewater, organic fertilizers (NPK sources), and culture-management additives such as sodium bicarbonate, together with background datasets from Ecoinvent, and represents a pioneering model within the Italian agri-food sector. Case studies are widely used in sustainability research to provide context-specific insights into environmental, social, and economic performance (Binder et al., 2010; Campagnolo et al., 2018). By situating the analysis in a real-world factory, this study contributes practical evidence to the broader debate on sustainable food systems (FAO, 2017).

Data collection combined both primary and secondary sources to ensure methodological robustness. Primary data were obtained from the factory records detailing inputs such as electricity, water, fertilizers, labor and packaging, as well as outputs including biomass yields. In addition, surveys and interviews were conducted with managers, workers, and consumers to evaluate social wellbeing and perceptions of organic spirulina. All the operational data correspond to April–November 2023 (seasonal operation). Secondary data were drawn from official databases (CREA, 2023; FAO FishStatJ, 2024), international standards, and peer-reviewed literature on spirulina production and sustainability (Belay, 2013). This triangulation of sources aligns with best practices in sustainability assessment, enhancing the reliability and validity of the study (Dantsis et al., 2010; De Olde et al., 2016).

Three complementary methodologies were applied to evaluate sustainability performance: Life Cycle Assessment (LCA) for environmental impacts, SAFA tool and citizen survey for social wellbeing, and Cost–Benefit Analysis (CBA) for economic viability. This single tripartite assessment approach reflects the multidimensional nature of sustainability (Hayati et al., 2011). To ensure that environmental, social, and economic findings are interpreted through a cross-dimensional synthesis logic, we applied an integrative synthesis approach that explicitly identifies cross-dimensional synergies and trade-offs. Specifically, we interpret LCA hotspot drivers (e.g., electricity demand for drying and circulation) jointly with CBA cost drivers and with SAFA/survey insights on labor performance and consumer affordability, so that improvement options are evaluated for their combined sustainability consequences rather than within one pillar only. Similar integrated approaches combining environmental and economic assessments have been applied in nursery plant production under pest outbreaks (Frem et al., 2022), in table grape production (Cardone et al., 2018), highlighting the value of coupling LCA with CBA for agri-food sustainability.

The LCA of organic spirulina production revealed a GWP of approximately 15 kg CO₂-eq per kilogram of dried biomass (Table 4). Other impact categories from the LCIA confirmed moderate environmental burdens: acidification at 0.10 kg SO₂-eq/kg, eutrophication at 0.03 kg PO₄³⁻-eq/kg, photochemical oxidation at 0.05 kg NMVOC, abiotic depletion at 0. 0.0002 kg Sb-eq/kg, water scarcity at −22.19 m³eq, and ozone depletion at 2.5828E−07 kg CFC-11-eq/kg. The largest contributor to GWP is electricity (high voltage grid supply) accounting for 7.21 kg CO₂ eq (approximately 47.97% of the total impact) (Figure 2), calculated using the standard Italian grid emission factor without renewable energy adjustments. Other notable contributors include sodium bicarbonate (4.56 kg CO₂ eq), treated wastewater (2.277 kg CO₂ eq), and organic nitrogen fertilizer (1.54 kg CO₂ eq), while molasses contribute 0.78 kg CO₂ eq. In contrast, emissions were avoided from the use of local tap water and electricity from the local grid, totaling −2.704 kg CO₂ eq. As such, these findings confirm Spirulina’s potential as a climate-friendly protein source, with the negative water scarcity value indicating a significant water-saving advantage due to the use of treated wastewater. Furthermore, the baseline GWP is 15.05 kg CO₂-eq per kg of dried spirulina. Varying grid electricity use by ±20% changes the GWP to 13.61–16.49 kg CO₂-eq/kg (−9.6 to +9.6% relative to baseline), confirming electricity as the dominant robustness lever. Varying sodium bicarbonate by ±20% changes the GWP to 14.14–15.96 kg CO₂-eq/kg (−6.1 to +6.1%). Varying treated wastewater/avoided tap water by ±20% changes the GWP to 14.65–15.45 kg CO₂-eq/kg (−2.6 to +2.6%). Varying photovoltaic electricity/avoided grid electricity by ±20% changes the GWP to 15.43–14.67 kg CO₂-eq/kg (+2.5% to −2.5%), indicating that increasing the renewable share provides a consistent (though smaller) reduction in climate impacts under the current grid/PV split (Table 5).

The SAFA-based social sustainability assessment demonstrated “best performance” (80–100%) in “Decent Livelihood” and “Human Safety and Health,” reflecting strong wage levels, workplace safety, and access to medical care. “Good performance” (60–80%) was observed in “Fair Trading Practices,” while “Labour Rights” and “Equity” also achieved “Good” (60–80%), outperforming conventional spirulina production systems. “Cultural Diversity” was assessed as not relevant for this case study. These results, as visualized in Figures 3, 4, highlight the social sustainability of the firm, which ensures decent working conditions, fair wages, and responsible practices within its organizational model.

Table 3 consolidates all the survey results in terms of demographics, awareness, affordability, health motivations, and cultural perception. These findings are descriptive and indicative of themes within this specific case context, not statistically generalizable to broader populations. The majority of whom were between 18 and 39 years old (35 respondents), with only three participants aged 40–60, and their educational backgrounds ranged from high school diplomas to bachelor’s, master’s, and professional degrees. Awareness of spirulina was high, with 89% of respondents familiar with the product and 17 demonstrating comprehensive knowledge and suggesting strong market penetration. In terms of affordability, 39% of participants considered organic spirulina expensive, 32% viewed it neutrally, and 11% found it affordable, while smaller proportions rated it very expensive (5%), very affordable (3%), or were unsure (5%). As such, price remains a barrier, with nearly 40% perceiving spirulina as expensive. Health-related motivations were particularly strong, as 58% reported consuming spirulina for its nutritional and health value, with others citing novelty, ease of integration into their diet, or sustainability as reasons. As such, nutritional and health benefits are the main drivers of consumption. Finally, cultural and social perceptions revealed mixed views: 24% believed spirulina respects and preserves local culture, 42% were uncertain, and 29% did not perceive such a contribution, indicating potential for improved cultural integration strategies. These findings emphasize that while the firm demonstrates excellent social sustainability performance, the production and consumption of spirulina directly influence citizens’ perceptions of wellbeing, highlighting the dual dimension of social sustainability: the enterprise’s practices and the product’s societal impact. As such, these insights suggest that within this local market context, awareness and health perceptions are strengths, while price remains a notable barrier for a substantial segment. The mixed cultural perceptions highlight an area for potential communication and product positioning strategies by the enterprise. The survey thus serves to contextualize the strong SAFA performance at the production level with the lived perceptions within the local consumer environment.

The economic evaluation demonstrated clear advantages for organic spirulina production compared to average Italian farms. Annual revenues reached €712,500, far exceeding the Italian farm average of €87,545 and even dairy cattle farms at €269,275. The gross margin (GM) was €332,993.32, while net income (NI) amounted to €110,872.02, both substantially higher than the national averages of €35,501 for farming businesses and €99,873 for dairy cattle. These results are detailed in Tables 6, 7. Labor profitability metrics also confirmed Spirulina’s efficiency: the enterprise reported 1,150 labor days per year, equivalent to 3 labor units (LU), with a labor income of €124,200/year. Productivity indicators showed revenue per labor hour at €103.26/h, compared to around €12/h for Italian farms, and GM per labor hour at €48.26/h, compared to around €8/h. As such, these results confirm spirulina’s economic viability as a sustainable agri-food innovation. Higher revenues and margins reflect strong market demand and efficient resource use. Labor profitability metrics also exceeded benchmarks, suggesting spirulina can provide decent livelihoods while remaining competitive in the Italian agri-food sector.

In our case of the dried organic spirulina production compares GWP with other sources of protein which is beef production so the GWP for 1 kg of dried organic spirulina production is 15.049 kg CO₂-eq. However, when considering protein content as the functional unit (FU), spirulina contains approximately 65–70% protein by dry weight. Using the higher estimate (70%), the GWP for 1 kg of Spirulina protein would be 21.5 kg CO₂-eq per kg protein, this value is significantly lower compared to the upper limit of 640 kg CO₂-eq per kg of protein and the average of 342.5 kg CO₂-eq per kg of protein for beef production. This suggests that organic spirulina production has a substantially lower carbon footprint when compared to traditional protein sources like beef as in Figure 5.

As shown in Table 8, the GWP of organic spirulina production (including processing impacts) is compared with results from Quintero et al. (2021), specifically with the seasonal cultivation Scenario 5 (ORP). This scenario is aligned with favorable seasons, avoiding winter production and eliminating the need for energy-intensive heating, leading to a low GWP of 15.5 kg CO₂-eq per kg biomass. Both the studied organic spirulina system and this seasonal ORP system exhibit very similar total GWP values (15.05 and 15.5 kg CO₂-eq/kg, respectively). Electricity and sodium bicarbonate are major contributors in both systems. In contrast, the standard year-round cultivation scenario has the highest GWP (28.2 kg CO₂-eq/kg), where thermal regulation and infrastructure significantly raise impacts compared to the organic case (15.05 kg CO₂-eq/kg).

Electricity use for drying and sodium bicarbonate inputs emerged as the main hotspots (48% of GWP), consistent with prior studies on microalgae cultivation (Cuellar-Bermudez et al., 2015; Fernández-Ríos et al., 2023). These findings align with prior studies emphasizing the need to optimize energy inputs and bicarbonate use to reduce environmental burdens (Cuellar-Bermudez et al., 2015; Fernández-Ríos et al., 2023). This dominance of electricity in GWP (48%) is mechanistically driven by energy-intensive unit processes specific to microalgae biorefining. Drying, required to stabilize biomass for food use, consumes significant thermal and/or electrical energy to remove water from a high-moisture slurry. Mixing and circulation in open raceway ponds, necessary to prevent sedimentation and ensure gas exchange, require continuous pumping. These processes contrast with conventional field crops where fertilization typically dominates impacts, highlighting different intervention points for sustainability improvement in algae systems. The negative water scarcity result (−22.20 m³eq, Table 3) reflects the advantage of using treated wastewater, a significant benefit in water-stressed Mediterranean regions. In addition, integrating renewable energy (e.g., geothermal, solar) and carbon capture (brewery CO₂, direct air capture) could further reduce emissions, making spirulina a viable ingredient for sustainable processed foods. Similarly, the notable contribution of sodium bicarbonate (30% of GWP) stems from its role as the primary inorganic carbon source for photosynthesis in closed systems; its production via the Solvay process is energy- and emissions-intensive. This highlights that sustainability improvements for spirulina must target process engineering (e.g., low temperature drying, efficient mixing design) and input sourcing (e.g., alternative carbon sources like captured CO₂) rather than agronomic practices.

Finally, the one-way sensitivity analysis reinforces the hotspot interpretation: climate results are most sensitive to grid electricity consumption (mixing/aeration, pumping, and drying) and to sodium bicarbonate supply, while changes in other inputs have comparatively smaller leverage at ±20%. From an improvement perspective, this prioritizes (i) process energy efficiency (especially low temperature drying and mixing optimization) and (ii) decarbonization of electricity supply (higher PV share or renewable procurement), together with exploring alternative inorganic carbon strategies (e.g., captured CO₂) to reduce dependence on industrial sodium bicarbonate.

The SAFA assessment revealed excellent performance particularly in livelihood and human safety and health themes, and good performance in fair trading practices, labor rights, and equity. These results should be interpreted with recognition of potential self-reporting bias in interview-based assessments; future studies would benefit from third-party audits or longitudinal monitoring. The consumer survey, while limited to a small, local sample (N = 38), provides contextual insights from the local survey aligned with the SAFA findings, indicating within this specific market context, high product awareness and strong health-related motivations among engaged citizens. This duality, between strong producer-level practices and varied consumer perceptions, underscores the multifaceted nature of social sustainability in niche food systems (El Bilali et al., 2020). Compared to broader Italian agricultural labor benchmarks (CREA, 2023), the enterprise’s labor metrics (€124,200 labor income, €103.26/h revenue per labor hour, Table 6) indicate favorable working conditions within its high-tech operational model, However, perceptions of affordability were mixed, and cultural connections were not strongly established, suggesting areas where enterprise communication and community engagement could be enhanced. These case-specific insights underscore the importance of complementing standardized social assessments (SAFA) with localized perceptual data to inform tailored business and communication strategies. In addition, these results highlight spirulina’s potential to contribute to social sustainability goals, including decent work and community wellbeing (Zahm et al., 2008; FAO, 2014; El Bilali et al., 2020). As such, organic spirulina can serve as a model for socially responsible agri-food innovation, but policies to improve affordability and consumer education are needed to broaden access.

Economic benchmarking (Table 7) shows that spirulina’s revenue per m² (€234.38) vastly exceeds conventional farming (€0.42/m²) and dairy (€0.70/m²). A more structurally relevant comparison with high-intensity greenhouse vegetables (estimated €45/m²) still shows spirulina’s superior areal productivity, though the gap is less extreme. This reflects spirulina’s biorefinery-like production model rather than direct comparability with traditional agriculture. Scalability is constrained by several factors: high sensitivity to energy costs (electricity constitutes a major operational expense), dependence on premium market positioning, and need for technical expertise. However, spirulina’s high labor productivity (€48.26 GM/labor hour vs. ~€8/h for Italian farms) suggests potential for decent livelihoods within technologically advanced agri-food niches. Electricity-cost sensitivity is material because annual electricity demand across mixing/aeration (15,574 kWh), lab/lighting (3,892 + 3,892 kWh), drying (31,148 kWh), and pumping/treatment (23,360 kWh) sums to 77,866 kWh/year in the case dataset. Using the baseline tariff applied in the CBA inputs (€0.20/kWh), this corresponds to around €15,573/year in electricity expenditure, which is embedded within the reported baseline net income. Holding all other variables constant, net income would increase by around €3,893 under a €0.15/kWh scenario and decrease by around €7,787 under a €0.30/kWh scenario relative to the baseline net income reported for the case.

These findings echo prior studies on microalgae profitability, which emphasize efficiency gains in resource use and market demand for functional foods (Costa et al., 2019; Mkindi et al., 2021). As such, spirulina production can diversify farm income streams and strengthen rural economies, particularly in regions with limited arable land.

Seasonal production adjustments would affect both annualized metrics: production cessation would increase GWP per kg through reduced annual output, while heating would increase absolute emissions. Economic returns would similarly be affected by either reduced revenue (from seasonal stoppage) or increased costs (from heating). These dynamics highlight the importance of climate-adapted cultivation strategies, such as seasonal planning or integration with waste-heat sources, to optimize annual sustainability performance.

Furthermore, the economic scalability of this organic spirulina model outside the Italian context depends on several interrelated factors. First, energy costs and sources are critical: in regions with lower electricity prices or higher renewable energy penetration, the operational costs, and thus net income, could be more favorable. Conversely, in areas reliant on fossil-based grids, both economic and environmental performance would diminish. Second, market development varies significantly: while Italy and the EU offer premium markets for organic, functional foods (Annunziata and Vecchio, 2016), other regions may lack consumer awareness or willingness-to-pay, affecting revenue potential. Third, climate conditions influence both productivity and operational costs: warmer climates could reduce or eliminate heating needs, improving annual yields and reducing energy burdens, whereas temperate regions would face seasonal constraints as noted in our limitations. Fourth, policy and subsidy frameworks differ: the EU’s Green Deal and Algae Initiative (Gerhard et al., 2023) provide supportive structures that may not exist elsewhere. Moreover, circular economy integration, such as access to treated wastewater or organic waste streams, depends on local infrastructure. Therefore, while the core bioprocessing model is transferable, its economic viability at scale will be context-specific, requiring adaptation to local energy systems, market structures, climate, and policy environments. Consequently, the findings of this study, alongside analyses of socio-economic risks in Mediterranean agriculture (Frem et al., 2021; Cardone et al., 2022; Nardelli et al., 2024), highlight that the transition to sustainable food systems requires models that simultaneously quantify positive sustainability outcomes and potential vulnerabilities.

This tripartite assessment reveals both synergies and trade-offs. The environmental hotspot (electricity) coincides with a major economic cost driver, suggesting that investments in renewable energy (e.g., solar, geothermal) could simultaneously reduce GWP and improve long-term economic resilience (Tzachor et al., 2022). Socially, strong labor performance supports economic viability through workforce stability and quality compliance. However, the “triple win” may be context-dependent: the model’s economic viability relies on premium pricing, which may conflict with social goals of accessibility and affordability, as indicated by survey responses (39% found spirulina expensive). Spirulina thus aligns well with circular bioeconomy principles, especially water recycling and nutrient reuse, but its sustainable scaling requires integrated strategies that address energy intensity, market development, and inclusive access.

The integration of spirulina into processed foods (e.g., pasta, snacks, dairy products) offers opportunities to enhance nutritional quality while reducing environmental footprints. Landscape-level approaches (Bozzo et al., 2022) illustrate how spatial and ecological dimensions intersect with economic sustainability, a perspective relevant for scaling spirulina production. As functional food innovation expands, spirulina can contribute to EU policy goals on sustainable consumption and production (Gerhard et al., 2023). The successful evaluation of this organic spirulina model aligns with calls for structured approaches to classify and assess novel agri-food innovations, as highlighted in recent sectoral reviews (Campobasso et al., 2025). As such, promoting spirulina-based processed foods could support healthier diets, reduce reliance on animal proteins, and advance circular bioeconomy strategies.

Results are based on one Italian factory, single case study, limiting generalizability. The consumer insights are derived from a small, exploratory sample (N = 38) within a localized market and are not statistically representative. Their value lies in providing qualitative context for this single case study, not in generalizable claims about consumer behavior. Findings are therefore presented as descriptive insights to inform local decision-making. Some inputs (e.g., packaging impacts, consumer survey sample size) may not fully capture variability. Seasonal variations in energy and water use were not fully modeled. The LCA assumed the average national electricity grid mix. Future assessments could explore scenarios with renewable energy integration, which would likely substantially reduce GWP, particularly given electricity’s dominant contribution (48%).

The foreground production and cost dataset used in this study corresponds to the facility’s seasonal operating window (April–November) as documented in the case-study data. Therefore, the reported economic and environmental results should be interpreted as performance under seasonal Mediterranean operation, rather than as a forced year-round (winter-heated) scenario. If production is reduced or stopped during winter months, annual output and revenues would decrease and fixed costs would be allocated over fewer kilograms, potentially worsening annualized indicators (e.g., NI per year and impacts per kg when annualized). Conversely, maintaining winter production would likely require supplemental heating and thus higher energy demand, which would increase GWP because electricity is already the dominant contributor to climate impact in this case.

This boundary choice is consistent with comparative evidence reported in the thesis, where seasonal cultivation scenarios show markedly lower climate impacts than year-round thermally regulated scenarios (e.g., 15.5 kg CO₂-eq/kg seasonal vs. 28.2 kg CO₂-eq/kg standard/year-round in a reference ORP system).

The LCA and CBA assume continuous annual production, while in practice, spirulina cultivation in Southern Italy is typically reduced or suspended during winter months (December–February) due to suboptimal temperatures unless supplemental heating is employed. This seasonal variation has dual implications: (i) Economic impacts: Annualized net income (€110,872) likely represents an optimistic scenario, as winter production cessation would reduce annual revenue proportionally. If production stops completely for 3 months, revenues could decrease by approximately 25%, potentially reducing net income to around €83,000–€90,000, depending on fixed cost coverage. Conversely, maintaining winter production with heating would increase energy costs substantially, potentially reducing net income through higher variable costs. The current CBA thus reflects optimal seasonal conditions rather than annual operational reality. (ii) Environmental impacts: The reported GWP (15 kg CO₂-eq/kg) assumes consistent production across seasons. Winter production cessation would effectively increase the carbon footprint per kilogram on an annual basis, as the same facility-level overhead emissions would be allocated to reduced annual output. Alternatively, winter heating, typically from natural gas or electricity, would significantly increase the GWP per kg biomass, particularly given electricity’s already dominant contribution (48% of GWP). Previous studies in Mediterranean climates estimate that heating can increase spirulina’s GWP by 40–60% compared to seasonal operations (Quintero et al., 2021; Fernández-Ríos et al., 2023). As such, future assessments should implement dynamic LCA and CBA models that account for seasonal temperature variations, heating requirements, and production scheduling to provide more accurate annual sustainability metrics for temperate regions.

Benchmarking against Italian farm averages provides context but may not reflect global competitiveness. In other words, the economic comparison with conventional farm averages, while informative for contextual positioning, should be interpreted with recognition of fundamental structural differences between extensive agriculture and high-tech bioprocessing systems. For future research, assessing spirulina sustainability at larger industrial scales and across diverse geographic contexts merit attention. Also, extend LCA to include downstream processing (e.g., incorporation into pasta, snacks) would be relevant to capture full product footprints. Moreover, exploring consumer willingness-to-pay and long-term adoption patterns for spirulina-based processed foods (Annunziata and Vecchio, 2016) would be interesting to capture consumer behavior. Furthermore, continuous monitoring and surveillance (El Handi et al., 2022), highlight the importance of robust data collection frameworks for sustainability assessments. To propose specific follow-up studies, such as a discrete choice experiment (DCE) for spirulina-based products, mirroring the methodology used in the sea urchin study (Petrontino et al., 2023b) to quantify WTP for specific attributes (organic, local, high-protein). Finally, future research should develop scenario-based techno-economic models that explicitly parameterize scaling factors (e.g., capital expenditure scaling exponents, operational efficiency curves) and incorporate probabilistic forecasts of energy costs to provide more robust guidance for investors and policymakers planning industrial-scale facilities.