Why does bacteria smell awful?

Question

old sponges and washclothes smell bad from fungi and bacteria right? What is it in these 2 things (which protein?) that makes them smell so bad, and how does it benefit them?

If anything you would think they would evolve to smell like roses so people would never rinse out their washclothes!

Answer 1

Because of the gases they produce!

Answer 2

Not all bacteria produce foul odors.  Some smell sweet, some smell musty, some smell sharp and acrid, and others smell rotten.  Generally the smell comes from metabolic byproducts.  Remember that bacteria, like all living things digest sources of food and produce waste products which smell bad.  Generally, protein (any type) digestion produces the stinkiest byproducts.  The reason why your stool smells so bad is due to bacteria - bacteria make up about 25% of the weight of f***s.

Molds (mildew) are what usually attack wet fabric/sponges.  They can survive under conditions that wouldn't support the growth of bacteria.