The medium was heat sterilised at 121 °C for 40 min to
achieve adequate heat penetration in the volume of medium. The
bacteria were grown in 5-l of broth at room temperature (20 °C) with
aeration (120 l/h) and harvested after 48 h incubation. Cell concentration
reached a mean of 1.27×109 cells/ml as determined by
direct counts using a Helber counting chamber