Q. About Protein Expression !!!

[Miss ELLA CHAN]

  Dear all,

  Could somebody kindly tell me at which OD600 will be the optimum
  condition for the induction of protein expression by using IPTG
  in bacterial strain ?

  I have been heard that we can start the induction at OD600=0.6, that 
  is the pre-log phase of the growing bacteria or we can do it at 
  OD600=1.5 which is the late log phase. Which condition should be the 
  best?

  Thanks so much for your help ! 

  Regards,
  
  Ella Chan 
  boella at uststu.ust.hk