The celstrep gene was expressed under the control of T7 RNA polymerase promoter in E. coli strain BL21 CodonPlus (DE3) RP. Protein expression was induced with 1 mM IPTG added to the cells grown until 1 OD600, for 6 hours at 37°C. 1 Uml-1 of Azo-CMCase activity was detected in the culture supernatant, and a similar activity level was revealed in the soluble fraction of intracellular proteins.