I worked in bioelectrochemostry. We had looked into that to see if we could juice reactors. Turns out it's not the bugs that limit things, but godamn did that stuff make them boogie.

There is also a Mycotoxin ATP Inhibitor called Tri-Nitro-Propionic Acid, which causes complete organ failure after a couple of days of being unconsious (because the body keeps attempting to create ineffective ATP and then starves). It generally only gets produced by certain fungal strains such as tropical Arthrinium, but can also be a very small percentage biproduct in some biofuel production methoda which utilize propionibacteria to conver grains and grasses similarly to how yeast creates alcohol.