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-D3-1

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 1.0g resin per 30ml medium was insignificant for the cell growth

however

it could improve the hEGF expression significantly. The batch culture in 2.5L 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 (225.0mg8226;L-1) could be achieved by supplementing 3.3g resin per 100ml medium.