Inoculum train

The medium used to produce the inoculum should be designed for rapid growth of the production organism without exopolysaccharide production. Production of the latter in the inoculum train can give rise to highly viscous cultures that are difficult to transfer from one vessel to another. 

Contamination of the production vessel leads to serious financial penalties and each step in the inoculum train is monitored for contamination. To reduce the risk of contamination during sampling it is usual to take a sample from the residue left in each vessel after its contents have been transferred to the next reactor. Since these contamination checks are retrospective, a heavy reliance is placed on the growth characteristics of the production organism. Kinetic variables such as growth rate and oxygen consumption rate are also used to assess the quality of the inoculum. 

How many transfers are required for inoculation of a 200 m fermentor, using a 10% inoculum train The initial transfer is the inoculation of a 200 ml shake flask with a lyophilised culture. 

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