Doing all the work. Microbes get no respect.
But also, can we attach these to natural methane producers? (Eg decomposing stuff or cows)
I think you're unfairly dismissing the massive amount of nanotech R&D and energy it takes to develop and operate the bazillion-unit cooperative mobile megafortress those bacteria are happily renting.
I'd guess waterfall then.
Maybe not in the mainstream?! But for many years people have had jobs specifically trying to get microbes to do useful work for us. [0]
Look up key terms like "directed evolution" in microbial research - which to me sounds like a fancy phrase for "breeding". But when breeding cycles can be measured in minutes across millions of units for something so small we can't see it... it kind of is a different thing so I guess it's fair to differentiate it.
Well, you know, there's brewing and bread. I like beer. I like sauerkraut. I like bread.
Insulin is handy. So is human growth hormone.
Why would they not be?
If you want to increase their number you need to give them a better environment.