Microbial transformation of quinic acid to shikimic acid by Bacillus megaterium, 2004
The production of shikimic acid from quinic acid (1.4 mM) using Gluconobacter oxydans as biocatalyst has been reported [18,19] with both whole cell catalyst and immobilized cell system (57% to 77% bioconversion). In the biotransformation, quinate dehydrogenase (QDH), a classical membrane-bound quinoprotein containing pyrroloquinoline quinine (PQQ) as the coenzyme functions as the primary enzyme in quinate oxidation converting quinic acid to 3-dehydroquinate (3-DHQ) (Figure 1) [9,18]. This 3-DHQ further gets converted to 3-dehydroshikimate (3-DHS) by 3-dehydroquinate dehydratase (DQD). Finally, 3-DHS gets converted to shikimic acid by the action of nicotinamide adenine dinucleotide phosphate (NADP)-dependent shikimate dehydrogenase (SKDH). Entry into the shikimate pathway from quinic acid seems to be advantageous over the classical pathway starting from glucose as there is less number of steps involved. From quinic acid, it is converted to shikimate by three enzymatic steps using microbial biotransformation