Adsorptive bioconversion of ethylene glycol to glycolic acid by Gluconobacter oxydans DSM 2003

An integrated bioprocess for the production of glycolic acid from ethylene glycol with Gluconobacter oxydans DSM 2003 and in situ product removal were investigated. A slight substrate inhibition was observed as substrate concentration was above 20 g/l and the product inhibition was much stronger. Bioconversion of glycolic acid is an end-product-inhibited reaction. In order to increase the productivity of glycolic acid and reduce the end-product inhibition of bioconversion, an adsorptive bioconversion for glycolic acid production from ethylene glycol catalyzed by resting cells of G. oxydans DSM 2003, was developed by using anion exchange resin D315 as the adsorbent for selective removal of glycolic acid from the reaction mixture. This approach allowed the yield of glycolic acid to be increased to 93.2 g/l, compared to 74.5 g/l obtained from a conventional fed-batch mode.