Abstract

Background and purpose: The 50 KDa protein (50 μg) in carboxylic domain of the neurotoxin heavy chain (BoNT/A-Hc) recognizes surface receptors on target neurons and this fragment contains the principle protective antigenic determinants. Recently, this fragment has been used as a recombinant vaccine candidate for botulism. The study aimed to compare the evaluation of BoNT/A-Hc production in fed-batch (high cell density cultivation) and batch cultivation of recombinant Escherichia coli (E. coli.). Materials and methods: In this research, growth of recombinant E. coli in batch culture was studied. In order to maximize protein expression, induction time and Isopropyl β-D-1-thiogalactopyranoside (IPTG) inducer concentration were optimized by the Taguchi statistical method. Then, fed-batch culture was applied to achieve high cell density cultivation. Finally, the recombinant protein expression level was determined. Results: In optimized conditions, 62 and 486 mg/l of soluble recombinant BoNT/A-Hc were produced in batch and fed-batch cultivation. Conclusion: According to the results, high cell density in fed-batch cultivation is a very effective for improve of recombinant proteins productivity.