Yield

The amount of growth which can be obtained from a particular compound is of great interest to microbiologists, especially when the production of the maximum amount of bio- mass is required for the minimum cost.  Substrates, such as pure glucose, are suitable for use on a small scale, but when tens or hundreds of liters of medium are to be made up the most efficient use of resources must be employed. Yield can be calculated simply by growing the same organism under the same conditions but with two different car- bon and energy sources. The maximum OD at the end of each experiment signifies the best yield. However, this comparison is only valid if there is some way of normalizing the amount of carbon source added. An industrial microbiologist might look at yield in terms of grams of biomass per unit of currency spent on the medium. Biochemically, it would be more suitable to look at grams biomass produced per mole of carbon. If enough is known about the biochemical route by which the carbon source is utilized, it would be possible to estimate how much ATP should be generated or consumed during metabolism –example for in comparison of the metabolism of glucose and lactose. This gives the concept of YATP the yield according to energy generated.

                                             Figure .  Diauxic growth of bacteria.