The potential of algae-based materials for carbon sequestration and energy savings in sustainable building design

Abstract

Microalgae are photosynthetic microorganisms known for their rapid growth, high photosynthetic efficiency, and diverse biochemical compositions. These characteristics make them promising agents for both ecological and industrial applications. Beyond their established roles in bioenergy, food, and pharmaceuticals, microalgae offer substantial environmental benefits, particularly in carbon dioxide (CO₂) sequestration and oxygen production. In urban environments, the Urban Heat Island (UHI) effect exacerbates local temperature increases, driven by heat-absorbing materials like concrete and asphalt, reduced vegetation, and high energy demand for cooling. This study investigates the potential of algae-based materials to address UHI impacts by acting as dual-purpose solutions for carbon sequestration and energy efficiency in sustainable building design. The research has three primary objectives: (i) to assess the impact of growth medium, pH, and photoperiod on the growth and chromaticity of green microalgae and cyanobacteria; (ii) to evaluate the ability of microalgae to sequester carbon under varying environmental stresses; and (iii) to explore the role of algae-based materials in modulating light intensity, thereby reducing indoor lighting requirements and lowering cooling energy consumption. The findings revealed that Pseudanabaena amphigranulata demonstrated optimal performance under a 12:12 light–dark cycle at pH 8, achieving a cell density of 2.4, a biomass of 0.87 g/L, and a carbon sequestration rate of 1.36 g/L CO₂e. This species also exhibited the highest chlorophyll absorbance (4.01) and effectively reduced indoor light intensity by 66.86%, from 1550 lux to 620 lux. These results highlight the significant potential of algae-based materials to enhance carbon sequestration and energy-saving capabilities in building design. In conclusion, this study underscores the multifunctional role of algae-based materials in creating climate-responsive, energy-efficient building systems. By integrating algae into sustainable design practices, this research positions algae-based materials as a valuable tool in mitigating UHI effects, reducing energy consumption, and promoting a resilient built environment.