Polysaccharide synergy of alginate/kappa carrageenan with microalgal system for sustainable heavy metal remediation.

As environmental pollution escalates, the need for sustainable and efficient bioremediation solutions has become increasingly urgent. Microalgae, with their inherent ability to capture and metabolize pollutants, offer a promising approach to wastewater treatment and environmental restoration. This, three-dimensional (3D) bioprinting of microalgae is emerging as a transformative environmental technology with significant potential for addressing critical ecological challenges. The advent of 3D bioprinting has now enabled the creation of optimized, high-surface-area structures that enhance the efficacy and stability of microalgae in bioremediation applications. Here we develop a novel method of fabricating Chlorophyceae Dunaliella tertiolecta encased within a hydrogel scaffold consisting of sodium alginate and kappa carrageenan crosslinked by cations (Ca2+ and K+). To accomplish well-designed and spatially defined patterns of microalgal cells with robust mechanical strength is challenging. But here we present a biocompatible 3D matrix for supporting microalgal cells with a substantially robust mechanical property. This study explores the sustainable fabrication of 3D bioprinted microalgae-laden constructs, employing eco-friendly biopolymers as support materials to enhance algal growth, pollutant uptake, and structural integrity. The bioprinted microalgae structures demonstrated robust performance in heavy metal adsorption and organic pollutant degradation, even under diverse wastewater conditions. Key findings indicate that the optimized 3D structures enable faster contaminant removal, higher reusability, and minimal environmental impact compared to traditional bioremediation approaches. This work highlights the potential of integrating 3D bioprinting and microalgae bioremediation as a scalable, sustainable strategy for wastewater treatment and environmental preservation. This approach not only contributes to cleaner water resources (SDG 6) but also supports climate action (SDG 13) through carbon sequestration, while fostering innovation in sustainable industrial practices (SDG 9).