Question

Bacterial cell lysis buffer composition protein extraction

Answer 1

First of all, sonication does not lead to protein denaturation provided you avoid overheating (sample kept on ice during sonication) and frothing (you have to check for foam formation). I use this method everyday to purify structured protein for crystallography without any problems.

If you do not want to use sonication, you can use high pressure lysis systems (french press) or high shearing force lysis systems (microfluidizer) that are thought to be more gentle than sonication.