Production of cell mass and ethanol yield

The manufacture of potable and industrial ethanol requires that as little substrate as possible is diverted into production of new cell mass. In theory, Ig of glucose should yield 0.511 g of ethanol and 0.489g of carbon dioxide but in practice, in batch aerobic fermentations, it is usually found that about 0.1 g of the glucose is diverted into new cell mass such that (Maiorella et al., 1981) 

More glucose can be converted to ethanol if cell recycle is used (Jackman, 1987) or by excluding a nitrogen source from the fermentation medium and using anaerobic conditions so that produced ethanol cannot be reconsumed. This principle was applied by Moebus and 

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