There are processes that have two names, despite it being same thing. One name called when it is good for humans, and another when it is bad for humans.
Let’s talk about tearing small, small things apart. Dissolving them and changing into something else, preformed by tiny, tiny organisms, living off these changes. There are leftovers after this. Waste.
When it is good, humans call it fermentation.
When it is bad, humans call it rotting.
Think about it next time in pub: you basically drink bacteria piss.