Colonies of bacteria grown on thin agar plate exhibit fractal patterns as a
result of adaptation to their environments. The bacterial colony pattern
formation is regulated crucially by chemotaxis, the movement of cells along a
chemical concentration gradient. Here, the dynamics of pattern formation in
bacterial colony is investigated theoretically through a continuum model that
considers chemotaxis. In the case of the gradient sensed by the bacterium is
nearly uniform, the bacterial colony patterns are self-similar, which they look
the same at every scale. The scaling law of the bacterial colony growth has
been revealed explicitly. Chemotaxis biases the movement of bacterial
population in colony trend toward the chemical attractant. Moreover, the
bacterial colonies evolve long time as the traveling wave with sharp front.Comment: 4 pages, 3 figures, accepted by Phys. Rev. E (Brief Report