I have been trying to express a protein using E. Coli strains (Rosetta and BL21) and am using LB and TB media. But both cultures have a very sharp acidic smell. I have tried for two weeks to express my protein but after centrifuge the cell pellet is very honey-like and no protein is expressed on SDS-PAGE!! I have tried plating and there are very nice single colonies.
Can anyone help me in finding the reason?