Author(s): W. T. Evert Ting, Chen-Hsuan Chiu and Chien-Chung Chen
Paper category: Proceedings
Book title: Proceedings of the Final Conference of RILEM 253-MCI Microorganisms-Cementitious Materials Interactions Volume II
Editor(s): Alexandra Bertron and Henk Jonkers
ISBN: 978-2-35158-207-7 (Set)
ISBN: 978-2-35158-210-7 (Volume 2)
e-ISBN: 978-2-35158-206-0
Publisher: RILEM Publications SARL
Publication year: 2018
Pages: 491-500
Total Pages: 308
Language : English

Abstract: To make bacteria based self-healing concrete, alkaline-resistant bacterial spores, growth substrates, and a calcium source are incorporated into a concrete matrix as self-healing agents. High concentrations (106~109 CFU/cm3 ) of spores were typically added to the concrete mix to ensure proper healing performance. It is essential to find a suitable medium for producing bacterial spores efficiently. In this study, we compared sporulation rates of four bacterial healing agents used in previous studies and two alkaline-resistant spore-forming bacteria isolated from an alkaline lake on six media at 30°C. Results of this study showed that sporulation rates of the six bacteria were greatly influenced by the growth medium used. The best sporulation medium for Bacillus pseudofirmus and B. cohnii was alkaline R2A agar (AR2A). Mean sporulation rates of the two bacteria were 93 and 99% respectively after incubation for 3 days. The best sporulation medium for Sporosarcina pasteurii was TSA agar supplemented with 2% urea (TSAU). Mean sporulation rate was 89% after incubation for 3 days. The highest mean sporulation rate (63%) of Lysinibacillus sphaericus was detected on R2A agar supplemented with 2% urea (R2AU) after incubation for 3 days. The most vigorous spore former was Bacillus cereus which reached 77, 83 and 89% mean sporulation rates after 1 day incubation on TSAU, sporulation agar supplemented with 2% urea (SAU), and R2AU respectively. Extending incubation period from 3 to 7 days did not significantly improve sporulation rates of these five bacteria. The best sporulation medium for Sporosarcina spp. was SAU. However, it required 7 days of incubation to achieve 91% mean spore rate.

Online publication : 2018
Publication type : full_text
Public price (Euros) : 0.00

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