Anaerobic digestion is a process in which organic matter, such as food waste or animal manure, is broken down by microorganisms in the absence of oxygen. This process occurs naturally in environments where there is no access to air and allows for the decomposition of complex compounds into simpler forms that can be utilized by other organisms. Anaerobic digestion is commonly used as a method of waste management, producing biogas (a mixture of methane and carbon dioxide) which can be used as an alternative energy source or as a fertilizer for agricultural purposes.