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Microbial induced carbonate precipitation (MICP) using Sporosarcina pasteurii has promising applications in soil stabilization and sustainable construction materials. MICP applications typically rely on freshly cultivated bacteria, although their storage stability is limited, as both urease activity and biomass decline within weeks (Erdmann et al. 2022; Mehring et al. 2021). The drying of bacterial cells for long-term storage and subsequent use after reactivation is common in various fields, such as for lactic acid bacteria in the food industry. Therefore, bacterial cells are dried using various methods, including freeze-drying or fluidized bed drying, either with or without using cryoprotectants such as maltodextrin, as applied in the present study (Hanisch et al. 2025). The organism S. pasteurii DSM33 was cultivated in bioreactors, subsequently prepared by centrifugation and used for freeze-drying or fluidized bed drying, with or without 15 % (w/w) maltodextrin as a protectant. After drying, the cell viability for each drying method was assessed by determining colony-forming units (CFUs). The dried bacterial cells were then stored under different conditions (room temperature, 4 °C, or 20 °C) for 92 days, with weekly measurements of urease activity. To evaluate whether the dried cells remained suitable for MICP applications, sand columns were prepared using the dried cells and compared to a freshly cultivated culture to assess the increase in column strength, based on the method according to Hanisch et al. 2024. Both drying methods produced powders that showed measurable urease activity, with freeze-dried samples with maltodextrin showing the highest viability (~21% relative to fresh culture). Storage of all dried bacterial cells at −20 °C proved most effective, resulting in a maximum urease activity loss of 22.63 % compared to the activity immediately after drying. Without maltodextrin as a cryoprotectant, the decline in urease activity during storage was slightly higher. All dried powders increased the uniaxial compressive strength of quartz sand columns through MICP, with values of up to ~10.8 N/mm² obtained using freeze-dried material, which were higher than those achieved with fluidized bed dried powders and comparable to the liquid culture controls. The results demonstrate that both drying approaches enable long-term storage of S. pasteurii, and that maltodextrin can improve stability and reactivation potential. These findings support the practical feasability of dried S. pasteurii for scalable, field-ready MICP applications in civil and geoengineering contexts.
Erdmann, Niklas et al. (2022): Sporosarcina pasteurii can be used to print a layer of calcium carbonate. In: Engineering in life sciences 22 (12), S. 760–768. DOI: 10.1002/elsc.202100074.
Hanisch, Patrick et al. (2025): Impact of drying methods and storage conditions on the reactivation of Sporosarcina pasteurii for microbial induced carbonate precipitation. In: Front. Mater. 12, Artikel 1616486. DOI: 10.3389/fmats.2025.1616486.
Hanisch, Patrick et al. (2024): The effect of different additives on bacteria adsorption, compressive strength and ammonia removal for MICP. In: Environ Earth Sci 83 (22). DOI: 10.1007/s12665-024-11929-z.
Mehring, A. et al. (2021): A simple and low-cost resazurin assay for vitality assessment across species. In: Journal of biotechnology 333, S. 63–66. DOI: 10.1016/j.jbiotec.2021.04.010.
| Country | Germany |
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