Microbials (Bacteria) are unique living organisms that live their life as a single cell for its entirety. Bacillus is a specific type of (genus) of bacteria which grow aerobically (with oxygen) and to some extent anaerobically (without oxygen and forms spores. Microbial pre-treatment, also known as pre-acidification or multi-stage fermentation, is a simple kind of pre-treatment technology in which the first steps of anaerobic digestion (hydrolysis and acidogenesis) are separated from acetogenesis and methanogenesis.