Quantitative Comparison of Recombinant Hc Domain of Clostridium Botulinum Neurotoxin A in Escherichia Coli in Batch and Fed-Batch Cultivations

Background and 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.). 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. In optimized conditions, 62 and 486 mg/l of soluble recombinant BoNT/A-Hc were produced in batch and fed-batch cultivation. According to the results, high cell density in fed-batch cultivation is a very effective for improve of recombinant proteins productivity.