Biofilm is a structure built by a community of bacteria. When the density of one type of bacteria is high, all the other bacteria sense that. At a certain point in the population density of those bacteria is reached, the bacteria realize that a “ quorum “ has been reached: they then begin to exude a material ( a complex carbohydrate-protein hybrid ) that binds them all together in an interlocked group. but, how does a nutrient affect a biofilm formation?