Biology of Backyard Composting
Composting involves a wide variety of organisms which are naturally present in organic matter.
The first decomposers to arrive in your compost pile are physical decomposers -- actinomycetes, fungi, redworms, sowbugs, slugs and snails. It is useful to be aware of their value, lest they be mistaken as pests.
Microbial decomposers, such as bacteria, perform the primary breakdown of organic materials and generate the heat associated with composting. Bacteria don’t have to be added to the compost pile. They are present virtually everywhere and enter the pile on every single bit of organic matter. Many types of bacteria participate in the composting process, thriving at different temperatures and on different materials.