Attachment on mortar surfaces by cyanobacterium Gloeocapsa PCC 73106 and sequestration of CO₂ by microbially induced calcium carbonate

Abstract

Cyanobacterial carbonate precipitation induced by cells and extracellular polymeric substances (EPS) enhances mortar durability. The percentage of cell/EPS attachment regulates the effectiveness of the mortar restoration. This study investigates the cell coverage on mortar and microbially induced carbonate precipitation. Statistical analysis of results from scanning electron and fluorescence microscopy shows that the cell coverage was higher in the presence of UV‐killed cells than living cells. Cells are preferably attached to cement paste than sand grains, with a difference of one order of magnitude. The energy‐dispersive X‐ray spectroscopy analyses and Raman mapping suggest cyanobacteria used atmospheric CO 2 to precipitate carbonates.

Impact of bacterial admixtures on the compressive and tensile strengths, permeability, and pore structure of ternary mortars: Comparative study of ureolytic and phototrophic bacteria

“…MIP peaks <0.004 μm were not observed likely due to spore durability [ 42 ] and EPS protection (Figure 6). [ 9,10 ] In contrast, Singh and Gupta [ 41 ] detected a decrease in compressive strength up to 39.67% compared to the control due to the higher cellulose fiber volume fraction compared to this study. Homogenously distributed fiber additions with immobilized Bacillus species have been found to improve compressive strength in concrete.…”

“…Yet, photoautotrophic strains have not been broadly considered for applications in mortar and cement repair besides in very few investigations which demonstrated an improvement in mortar properties and reduction in CO 2 footprint resulting from an addition of phototrophs. [9][10][11][12] However, no studies exist so far that compare heterotrophic and photoautotrophic microbial species for mortar and cement biotechnology.…”

“…Synechocystis, Synechococcus, and Gloeocapsa cyanobacteria species were able to adhere to mortar surfaces and successfully precipitated carbonates in both live and UV-killed states when incubated with a calcium and a carbonate source. [9,10] Photosynthetic organisms shift the calcium carbonate equilibrium to calcium carbonate production because of photosynthesis. Bacterial cells can increase the local calcium oversaturation through binding of Ca 2+ on the cell surface and on the EPS.…”

Influencing factors on ureolytic microbiologically induced calcium carbonate precipitation for biocementation

“…(3) Oxygenic photosynthesis Gloeocapsa sp. PCC 73106 (Zhu et al 2021) Synechococcus pevalekii BDHKU 35101 (Sidhu et al 2022) Tolerance of most strains to alkaline environment No toxic by-products Cheap media for cultivation CO 2 limitation in sand Light dependent Slow growth rates during phototrophic cultivation Dhami et al (2014), Zhu et al (2015) Ureolysis Sporosarcina pasteurii (Ma et al 2020;Zhao et al 2019) Bacillus sphaericus (Sharma et al 2022) Bacillus cereus (Oualha et al 2020) Bacillus megaterium (Mukherjee et al 2022) Easy to control Cheap media components High calcium carbonate precipitation rates High tolerance of strains to alkaline enviroment Toxic ammonia as byproduct Production of urea coupled to CO 2 emissions Hammes and Verstraete (2002), Muynck et al (2010a), Stocks-Fischer et al (1999) Denitrification Castellianelle denitrificans (Jin et al 2022) Pseudomonas denitrificans (Hamdan et al 2017) By-products calcium formiate and calcium nitrate are commercial additives for cement Nitrite ions can inhibit corrosion Usage of carriers for alkaline environments necessary Erşan et al (2016) precipitation. The creation of the advantageous microenvironment results in the formation of crystals on the cell surface, ensuing in the encapsulation of the cell (Muynck et al 2010a).…”