Production and accumulation of toxic by-products such as acetic acid can inhibit the growth of recombinant cells and the expression of exogenous gene in E.coli. An anionic exchange resin, A-D 3-1, which is high in adsorption selectivity and capability for acetic acid, was screened from a variety of resins based on its physical and chemical properties.On the scale of shake flask culture, the addition of 1.0 g resin per 30 ml medium was insignificant for the cell growth, however,it could improve the hEGF expression significantly. The batch culture in 2.5 L fermentor showed that in-situ adsorption of acetic acid by anionic exchange resin could enhance the expression level of interested protein and reduce the fermentation period by 2 hours. And up to 10% improvement of hEGF (human epidermal growth factor)volumetric productivity (225.0 mg·L -1 ) could be achieved by supplementing 3.3 g resin per 100 ml medium.
