Microbial Production of Cis,Cis-Muconic Acid By Klebsiella Pneumoniae.

The microbial production of bio-based chemical becomes an important approach in the chemical industry. Here we report the microbial production of cis,cis-muconic acid(CCMA) that is the precursor of adipic acid and terephthalic acid. The CCMA was produced through the aromatic amino acid synthesis route in Klebsiella pneumoniae. This microorganism has the genes related to the production of CCMA from glucose as a carbon source, which are not normally activated in wild type condition. When we blocked the synthesis of aromatic amino acid, Klebsiella pnuemoniae could produce not only CCMA but catechol that is the last intermediate of CCMA production pathway. After endogeneous catechol 1,2-dioxygenase was overexpressed, the accumulated catechol is converted to CCMA. We further improved the pathway by inactivating several unnecessary genes and developed the strain to produce 2g/L of CCMA in flask cultivation. Furthermore, we optimized aeration and pH for fed-batch fermentation.