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 BmR1 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 BmR1 recombinant antigen. Cells were grown at a controlled specific growth rate (mu(set)) during pre-induction, followed by constant feeding postinduction. The highest biomass (24 center dot 3 g l-1) was obtained during fed-batch process operated at mu(set) of 0 center dot 15 h-1, whereby lower mu(set) (0 center dot 075 h-1) gave the highest protein production (9 center dot 82 mg l-1). The yield of BmR1 was increased by 1 center dot 2-fold upon induction with 1 mmol l-1 IPTG (isopropyl-beta-d-thiogalactoside) compared to using 5 mmol l-1 and showed a further 3 center dot 5-fold increase when the culture was induced twice at the late log phase. Conclusions: Combination of feeding at a lower mu(set) and twice induction with 1 mmol l-1 IPTG yielded the best result of all variables tested, promising an improved method for BmR1 production. Significance and Impact of the Study: This method can be used to increase the production scale of the BmR1 recombinant antigen to meet the increasing demand for Brugia Rapid (TM), a commercial diagnostic test for detection of brugian filariasis.