I've usually induced my recombinant protein in E.Coli with 0,5 mM IPTG when A600 has reached 0,5-0,6. However last time I accidentally let the culture grow to 1,0 and the results have been confusing. It seems that I have got an almost 200% increase in the amount of my recombinant protein. I can't find any articles explaining this as according to my understanding when A600 has reached 0,9 the cells enter stationary phase of growth and recombinant yields should drop when inducing. Has anybody got an explanation or ideas? I would be very grateful.