Gram-positive bacteria own a thick cell wall comprising of many layers of peptidoglycan and teichoic acids. In contrast, Gram-negative bacteria have a relatively thin cell wall consisting of a few layers of peptidoglycan surrounded by a second lipid membrane containing lipopolysaccharides and lipoproteins.
Bacteria-based self-healing concrete is a construction material used to repair cracks in concrete, in which bacteria carriers immobilize the bacterial spores.
When engineering multiple microorganisms for a similar output, a self-healing technique using bacteria can fill the cracks in concrete by inducing calcium carbonate precipitation through biomineralization. The basic mechanism of bacteria-based crack healing happens when the concrete crack occurs. The water will then leak via the formed cracks and the capillary pores of concrete [4 ]. With the presence of water and nutrients inside the concrete matrix, the germination of bacteria will take place, and the limestone produced can fill the cracks.