Bacillus sphaericus LMG 22257 is physiologically suitable for self-healing concrete

Jianyun Wang, Henk M. Jonkers, Nico Boon, Nele De Belie

Research output: Contribution to journalArticleScientificpeer-review

39 Citations (Scopus)


The suitability of using a spore-forming ureolytic strain, Bacillus sphaericus, was evaluated for self-healing of concrete cracks. The main focus was on alkaline tolerance, calcium tolerance, oxygen dependence, and low-temperature adaptability. Experimental results show that B. sphaericus had a good tolerance. It can grow and germinate in a broad range of alkaline pH. The optimal pH range is 7 ∼ 9. High alkaline conditions (pH 10 ∼ 11) slow down but not stop the growth and germination. Oxygen was strictly needed during bacterial growth and germination, but not an essential factor during bacterial urea decomposition. B. sphaericus also had a good Ca tolerance, especially at a high bacterial concentration of 108 cells/mL; no significant influence was observed on bacterial ureolytic activity of the presence of 0.9M Ca2+. Furthermore, at a low temperature (10 °C), bacterial spores germinated and revived ureolytic activity with some retardation. However, this retardation can be counteracted by using a higher bacterial concentration and by supplementing yeast extract. It can be concluded that B. sphaericus is a suitable bacterium for application in bacteria-based self-healing concrete.

Original languageEnglish
Pages (from-to)5101-5114
Number of pages14
JournalApplied Microbiology and Biotechnology
Issue number12
Publication statusPublished - 1 Jun 2017


  • Alkaline tolerance
  • Bio-CaCO
  • Ca tolerance
  • Oxygen dependence
  • Temperature adaptability
  • Ureolytic activity


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