Carbohydrates are organic molecules that contain carbon, hydrogen and oxygen in the ratio (CH2O)n. Organisms use carbohydrate differently depending upon their enzyme complement. The pattern of fermentation is characteristics of certain species, genera or groups of organisms and for this reason this property has been extensively used as method for biochemical differentiation of microbes. Glucose after entering a cell can be catabolized either aerobically in which molecular oxygen can serve as the final electron acceptor indicating oxidative metabolism or anaerobically in which inorganic ions other than oxygen, e.g. NO3¯ or SO4¯ ¯ can serve as the final electron acceptor indicating fermentative metabolism or both aerobic and anaerobic pathways and some organism lack the ability to oxidize glucose by either
