Compared to the traditional chemical process, a biotechnological process using whole cell biocatalystsis was characterized by low productivity because of product inhibition, which leads to the production of biorefinery chemicals via fermentation economically infeasible.

Researchers from the Institute of Process Engineering (IPE), Chinese Academy of Sciences, reported an approach to increase the productivity of fermentation via removing the inhibitory product from the vicinity of the biocatalyst as soon as it is formed. Appropriate in situ Product Removal (ISPR) techniques were selected according to the physicochemical properties of the target product to represent the general coordination of upstream, reaction and downstream technologies.

An integrated fermentation system was developed to couple fermentation and in situ product separation using the expanded bed adsorption (EBA) (See Figure 1). EBA itself was a coupled process that combined solid-liquid separation and product recovery into a single unit operation.

Based on these advantages, succinic acid, as one of building-block chemicals, was used to test the system efficiency. The novel approach during the product inhibitory period of microbial fermentation enhanced the cell growth of A. succino genes from 48 h to 126 h, and significantly increased succinic acid production up to the final titer of145.2 g l？1 with an average yield of 0.52 g g？1, and productivity of 1.3 g l？1 h？1.

This work was supported by State Major Basic Research Development Program of China (Grant2007CB714305), the Knowledge Innovation Program of the ChineseAcademy of Sciences (Grant No. KSCX2-EW-G-2-2), National High Technology Research and Development Program of China (Grant 2011AA02A203). The results were published in Biochemical Engineering Journal.

Contact:

LIQiang (qiangli@home.ipe.ac.cn), XING Jianmin (jmxing@home.ipe.ac.cn)

Institute of Process Engineering, Chinese Academy of Sciences.

Figure1 Overall process set-up of fully integrated expanded bed adsorption in a technical scale fed-batch process for ISPR process, (A) simulation image, (B) equipment image (Image by IPE)