Carbon capture through 3D bioprinting and in situ biomineralization: investigation of physical and mechanical properties

Global warming has fostered the development of new technologies to convert CO 2 to valuable products. Inspired by natural mineralization mechanisms, this study presents a novel approach to capture CO 2 through microbial mineralization in 3D-printed bioconstructs. The proposed approach employs biocatalytic carbon capture facilitated via carbonic anhydrase enzyme produced by Sporosarcina pasteurii bacteria. Therefore, the developed living bactoink is capable of capturing CO 2 by in situ biomineral trapping (i.e., transforming CO 2 to CaCO 3 in the printed constructs). For this purpose, the optimized blend of carboxymethyl cellulose and alginate is first obtained to prepare the required hydrogel basis of bactoink. Next, the bactoink comprising bacteria and hydrogel is prepared, and its printability is assessed. Finally, a comprehensive evaluation of the physical properties and mechanical performance of the printed constructs is conducted after their exposure to CO 2 . The CaCO 3 precipitation is confirmed by SEM, XRD, and Raman spectroscopy. The method shows rapid strength gain of the printed bio-constructs, achieving up to 8.6 MPa after 2 days of mineralization, highlighting promising characteristics for real-world applications. These findings underscore the potential of biocatalytic 3D-printing as a viable strategy for sustainable carbon capture and utilization. Furthermore, unlike common microbially induced carbonate precipitation (MICP) techniques, our proposed method relies on direct microbial CO 2 capture, effectively reducing undesirable by-products such as ammonium ions produced in conventional ureolytic MICP. 3D bioprinting of living CO 2 absorbing constructs not only facilitates the synthesis of bioinspired materials for industrial and biomedical applications but also advances construction technology for earth and extraterrestrial settlements.