The present invention is drawn to processes for biologically controlling T7 expression system in Recombinant Escherichia coli strain BL21(G2) by using heat. The strain BL21(G2) are useful to produce a variety of heterogonous proteins. Also disclosed is a biologically large scale operations of the strain BL21(G2), it is convenient to carry out the culture in a fermentation tank with stage input system.
