Hi Ritaja Chattopadhyay

We have tried to purify recombinant proteins in this way. The following suggestions may help you. a) Extend the incubation time (with IPTG and antibiotics), 10-12 hours may be better. b) How about the time of sonication? Adding lysozyme and ultrasonic lysate in an ice bath for 30 mins was the way we often use it. ​c) Too much or not enough lysate buffer leads to a low yield. ​We used 10ml lysate for each gram of bacterial precipitation.

Try to share more detailed steps of the experiment, maybe we can find more problems.