Vitamin B by nature is a Microbe. the different B's were named from spinning yeast in a centrifuge. B1 settled first, b12 later.
Before the advent of Synthetic fertilizers and chemicals, B12 was found in the soil. Wild foods from an old growth forest is the best option at the moment, worms work too. Its also found on the skin of fruits and vegetables, when grown organically, also the pollens of flowers. There is a particular flower thats highest, but having trouble remembering the name right now.