FIG 2.

Images of cracked and healed mortars treated with wild-type and modified bacteria. Spores of B. subtilis with the biosilicification gene were incorporated into a cracked mortar on day 0, and the cracked mortar was incubated with a rich bacterial growth medium for 28 days. (A and B) T-B. subtilis, B. subtilis carrying the biosilicification gene; (C and D) control, no bacterial treatment; (E and F) B. subtilis, wild type. (All images are reprinted from reference 80 with permission of the publisher [copyright 2015, Royal Society of Chemistry].)