"..The chemical dissolution of materials by bacteria or other biological means"... "Organic material can be degraded aerobically with oxygen, or anaerobically, without oxygen. A term related to biodegradation is biomineralisation, in which organic matter is converted into minerals. Biosurfactant, an extracellular surfactant secreted by microorganisms, enhances the biodegradation process.
Biodegradable matter is generally organic material such as plant and animal matter and other substances originating from living organisms, or artificial materials that are similar enough to plant and animal matter to be put to use by microorganisms."
Note: Products that contain biodegradable matter and non-biodegradable matter are often marketed as biodegradable. Source: Wikipedia