Extractive Fermentation Employing Ion-Exchange Resin to Enhance Cell Growth and Production of Metabolites Subject to Product or By-Product Inhibition

In recent years, commercial production of proteins and metabolites from microbial fermentation for industrial applications has increased significantly. Innovative approaches are directed towards the improvement of the conventional batch fermentation method and the segregated downstream processing of target product to improve the overall process efficiency and to ensure that the process is economically viable. Feedback inhibition is a common problem faced during fermentation process when the concentration of end-product/by-product reaches a certain level. The excessive accumulation of end-product/by-product in the culture may inhibit the growth of cell and represses the secretion of target metabolite. In the production of many fermentative products such as antibiotics, amino acids, and fungal metabolites, a serious problem of feedback inhibition is often encountered. Cultivation of lactic acid bacteria and recombinant bacteria is usually subjected to by-product inhibition. Hence, extractive fermentation via in situ ion-exchange-based adsorptive technique is a possible approach to be used industrially to mitigate feedback inhibition, aimed at enhancing fermentation performance. In this chapter, advances in this area were presented. Strategies to overcome problem related to product/by-product inhibitions by this technique via dispersed, external, and internal resin system, and the general methodology in the implementation of the technique were also discussed.