Comprehensive microbiological studies on screening bacteria for self-healing concrete

Influencia de las bacterias en la autocuración del concreto

“…Por otro lado, se utilizaron como agentes de autocuración, especies de Bacillus de tipo no patógeno, como Bacillus subtillis, Bacillus cereus, Bacillus licheniformis y Bacillus halodurans, mediante el estudio microbiológico denominado el proceso de tinción de Gram se identificó que los cuatro cultivos seleccionados son bacterias grampositivas y con forma de bastón, en el caso del medio de composición del hormigón, el B. halodurans ha mostrado la tasa de crecimiento más alta y ha mostrado un valor de velocidad de pulso ultrasónico de 4,6 km/s y con un 1,71% de absorción de agua, que es óptimo entre otros cultivos bacterianos, se recomienda el uso de B. halodurans como agente autocurativo en los trabajos de reparación del hormigón [37].…”

Humic Acid-Amended Formulation Improves Shelf-Life of Plant Growth-Promoting Rhizobacteria (PGPR) Under Laboratory Conditions

“…These spores can survive in hostile conditions for many years without necessary nutrition, and it is a type of PGPR with a short shelf-life due to its structural, and cellular components (Luu et al, 2022). Many factors influence a Bacillus spore's resistance to heat, strong proteinaceous coats, peptidoglycan cortex, moderate moisture content, and large amounts of di-picolinic acid and divalent cations within the spore core are all present (Durga et al, 2021;Cho & Chung, 2020;Mukherjee et al, 2022). Moreover, B. subtilis secretes extracellularly during nutrient scarcity, attempting to kill proteins that affect programmed cell death in siblings, releasing nutrients and allowing a portion of the population to expand.…”

Self-Healing of Cementitious Materials via Bacteria: A Theoretical Study

“…The ability of a large community of bacteria to transform a suitable nutrient source into insoluble calcite crystallites-known as microbially induced calcium carbonate precipitation (MICP)-has been used as a part of biotechnologies representing an alternative to traditionally applied methods. Among others, MICP is exploited in dentistry [1], soil bioconsolidation [2][3][4], grouting technologies [5,6], water remediation [7,8], conservation of stone artworks [9,10], and, in particular, civil engineering [11][12][13][14][15]. The formation of calcium carbonate (CaCO 3 ) requires the presence of sufficiently high concentrations of calcium cations (Ca 2+ ) and carbonate anions with a saturation level greater > 1 [16].…”

“…In this field of research, there are many detailed studies dealing with related subproblems, for example, the application of self-healing techniques [21], the selection of suitable bacteria species [15,22], and the optimal location of the bacterial inoculate on the material surface [23]. It must be clarified, however, that the analytical solutions of balance equations modelling the bacterial growth followed by subsequent analysis of the influence of external/internal conditions on the growth curves is not frequently applied in the literature.…”

“…The principal objective of the presented study is to theoretically follow the predictive microbiology and model the sensitivity of the exponential stage of bacterial growth on such individual parameters. However, it should be noted that in this field of research there exist many detailed studies dealing with related subproblems-for example, the application of selfhealing techniques [21], the selection of suitable bacteria species [15,22], and the optimal location of the bacterial inoculate on the material surface [23]-but analytical solutions of balance equations modelling bacterial growth followed by subsequent analysis of the influence of external/internal conditions on the growth curves are not frequently applied in the literature. It remains to be studied whether or not the bacterial growth curve can serve as an acceptable predictive indicator that allows one to estimate the rate of carbonate formation in cracked concrete.…”