Abstract

The present study investigates the production kinetics of recombinant human tumor necrosis factor-alpha (TNF-α) in Escherichia coli under three different nonconventional inducible expression systems, namely, salt, the thermal, and auto-inducible system in batch culture in a bioreactor. A codon-optimized synthetic gene of human TNF-α was inserted into plasmid pET-14b under T7 promoter to obtain its plasmid-based expression in E. coli. Very high specific yield (~47% of total cellular protein (TCP)) was obtained with auto-inducible expression system. The thermal and salt-induced expressions could yield up to ~30% and ~17% of TCP, respectively. Maximum specific productivities were reported to be 0.092 g/gDCW/h, 0.1 g/gDCW/h, and 0.079 g/gDCW/h for auto-inducible, thermal-inducible, and salt-inducible expression systems, respectively.

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