Optimizing Bacillus pasteurii spore germination and unveiling impermeability mechanisms in microbial self-healing concrete

This study investigated the impact of key factors on spore germination of Bacillus pasteurii, a self-healing bacterium for concrete, and elucidated its impermeability mechanism to provide theoretical and practical guidance for advanced self-healing concrete development. Controlled experiments determ...

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Main Authors: Yingying Hu, Weitao Liu, Yutao Zhang, Xuelong Hu
Format: Article
Language:English
Published: Frontiers Media S.A. 2025-08-01
Series:Frontiers in Microbiology
Subjects:
Online Access:https://www.frontiersin.org/articles/10.3389/fmicb.2025.1653557/full
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author Yingying Hu
Weitao Liu
Yutao Zhang
Xuelong Hu
author_facet Yingying Hu
Weitao Liu
Yutao Zhang
Xuelong Hu
author_sort Yingying Hu
collection DOAJ
description This study investigated the impact of key factors on spore germination of Bacillus pasteurii, a self-healing bacterium for concrete, and elucidated its impermeability mechanism to provide theoretical and practical guidance for advanced self-healing concrete development. Controlled experiments determined optimal germination conditions: 2 g/L microcapsule concentration, pH 8, and 1 g/L inosine, yielding peak germination efficiency that highlights parameter synergies. Thermal stimulation for 3 minutes effectively triggered germination, presenting a practical activation approach. MIP and SEM analyses were employed to characterize concrete microstructure. Results showed the alkaline concrete matrix facilitated B. pasteurii physiology, while Ca2+ had no inhibitory effect, enabling calcium-based additives in formulations. B. pasteurii-containing mortar enhanced cement hydration stability; MIP revealed self-healing concrete had an infiltration fractal cone number of 2.832 and trunk fractal dimension of 2.306, similar to conventional materials, indicating no increased structural complexity. Environmental erosion primarily affects 300–10,000 nm pores, pinpointing durability targets. SEM and MIP analyses confirmed B. pasteurii-induced vaterite and aragonite calcium carbonate crystals integrated with tobermorite, reducing porosity and enhancing mechanical strength. These findings indicate the bacterium’s potential in self-healing systems, though future research should address complex physicochemical influences and bacterial gradient domestication to improve environmental adaptability.
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spelling doaj-art-d34ba3de7c564ead8280a458de5dca392025-08-20T03:40:45ZengFrontiers Media S.A.Frontiers in Microbiology1664-302X2025-08-011610.3389/fmicb.2025.16535571653557Optimizing Bacillus pasteurii spore germination and unveiling impermeability mechanisms in microbial self-healing concreteYingying Hu0Weitao Liu1Yutao Zhang2Xuelong Hu3Shandong Key Laboratory of Eco-Environmental Science for the Yellow River Delta, Shandong University of Aeronautics, Binzhou, ChinaCollege of Energy and Mining Engineering, Shandong University of Science and Technology, Qingdao, ChinaShandong Key Laboratory of Eco-Environmental Science for the Yellow River Delta, Shandong University of Aeronautics, Binzhou, ChinaKey Laboratory of Safety and High-Efficiency Coal Mining, Ministry of Education, Anhui University of Science and Technology, Huainan, ChinaThis study investigated the impact of key factors on spore germination of Bacillus pasteurii, a self-healing bacterium for concrete, and elucidated its impermeability mechanism to provide theoretical and practical guidance for advanced self-healing concrete development. Controlled experiments determined optimal germination conditions: 2 g/L microcapsule concentration, pH 8, and 1 g/L inosine, yielding peak germination efficiency that highlights parameter synergies. Thermal stimulation for 3 minutes effectively triggered germination, presenting a practical activation approach. MIP and SEM analyses were employed to characterize concrete microstructure. Results showed the alkaline concrete matrix facilitated B. pasteurii physiology, while Ca2+ had no inhibitory effect, enabling calcium-based additives in formulations. B. pasteurii-containing mortar enhanced cement hydration stability; MIP revealed self-healing concrete had an infiltration fractal cone number of 2.832 and trunk fractal dimension of 2.306, similar to conventional materials, indicating no increased structural complexity. Environmental erosion primarily affects 300–10,000 nm pores, pinpointing durability targets. SEM and MIP analyses confirmed B. pasteurii-induced vaterite and aragonite calcium carbonate crystals integrated with tobermorite, reducing porosity and enhancing mechanical strength. These findings indicate the bacterium’s potential in self-healing systems, though future research should address complex physicochemical influences and bacterial gradient domestication to improve environmental adaptability.https://www.frontiersin.org/articles/10.3389/fmicb.2025.1653557/fullself-healing concreteimpermeabilityBacillus pasteuriispore germinationgermination conditionsconcrete durability
spellingShingle Yingying Hu
Weitao Liu
Yutao Zhang
Xuelong Hu
Optimizing Bacillus pasteurii spore germination and unveiling impermeability mechanisms in microbial self-healing concrete
Frontiers in Microbiology
self-healing concrete
impermeability
Bacillus pasteurii
spore germination
germination conditions
concrete durability
title Optimizing Bacillus pasteurii spore germination and unveiling impermeability mechanisms in microbial self-healing concrete
title_full Optimizing Bacillus pasteurii spore germination and unveiling impermeability mechanisms in microbial self-healing concrete
title_fullStr Optimizing Bacillus pasteurii spore germination and unveiling impermeability mechanisms in microbial self-healing concrete
title_full_unstemmed Optimizing Bacillus pasteurii spore germination and unveiling impermeability mechanisms in microbial self-healing concrete
title_short Optimizing Bacillus pasteurii spore germination and unveiling impermeability mechanisms in microbial self-healing concrete
title_sort optimizing bacillus pasteurii spore germination and unveiling impermeability mechanisms in microbial self healing concrete
topic self-healing concrete
impermeability
Bacillus pasteurii
spore germination
germination conditions
concrete durability
url https://www.frontiersin.org/articles/10.3389/fmicb.2025.1653557/full
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