Effects of feeding and induction strategy on the production of BmR1 antigen in recombinant E. coli

Aim:  To investigate the effects of feeding and induction strategies on the production of Bm R1 recombinant antigen.
Methods and Results:  Fed-batch fermentation was studied with respect to the specific growth rate and mode of induction to assess the growth potential of the bacteria in a bioreactor and to produce high yield of Bm R1 recombinant antigen. Cells were grown at a controlled specific growth rate (μ_set) during pre-induction, followed by constant feeding postinduction. The highest biomass (24·3 g l^?1) was obtained during fed-batch process operated at μ_set of 0·15 h^?1, whereby lower μ_set (0·075 h^?1) gave the highest protein production (9·82 mg l^?1). The yield of Bm R1 was increased by 1·2-fold upon induction with 1 mmol l^?1 IPTG (isopropyl-β- d -thiogalactoside) compared to using 5 mmol l^?1 and showed a further 3·5-fold increase when the culture was induced twice at the late log phase.
Conclusions:  Combination of feeding at a lower μ_set and twice induction with 1 mmol l^?1 IPTG yielded the best result of all variables tested, promising an improved method for Bm R1 production .
Significance and Impact of the Study:  This method can be used to increase the production scale of the Bm R1 recombinant antigen to meet the increasing demand for Brugia Rapid^?, a commercial diagnostic test for detection of brugian filariasis.