Abstract: “This study focused on identification of denitrifiers that can be used to achieve microbial self-healing concrete. By using heat treatment and minimal medium, 9 denitrifying strains were isolated from soil. Upon identification of the strains, their capability of handling dehydration stress was investigated. Qualifying 7 strains were further investigated at N:P ratio of 70:1. Finally, 2 strains, Pseudomonas aeruginosa and Diaphorobacter nitroreducens, were selected and investigated at pH 7, pH 9.5 and pH 13 with and without protection. As a protective carrier diatomaceous earth and expanded clay were used. Significant activity observed at pH 9.5 and with protection both strains could survive pH 13 for 14 days and reduced 20-30 mg/L NO3- in 4 days after the pH adjustment to ~10. Overall, the results indicated that Pseudomonas aeruginosa and Diaphorobacter nitroreducens can resist mild heat, dehydration, starvation and relatively alkali environment, which are the main concerns in use of ba”

Keywords: alkali pH, self-healing, Gram-negative, phosphorus limitation