[pazimzadeh]

Hence the importance of feeding your microbes in a predictable manner, with something that is not too easy to digest but calms them down so that they don't overrun the place.

Mucus acts as both a barrier and a food source with an extremely diverse O-linked glycans which decorate its backbone. ~800k permutations of the 5 possible O-linked if you consider a glycan chain of length 5, and 3 possible linkages types. In actually the diversity is likely greater given chain branching patterns, randomized expression of glycosyl hydrolases which generate the mucus, etc..