Fig. 1.

Crc regulation of metabolic pathways for production of muconate in the engineered strain, P. putida KT2440-CJ102 (Vardon et al., 2016). The lignin monomers p-coumarate and ferulate are metabolized via protocatechuate, which is redirected to catechol by deletion of pcaHG and integration of aroY, which encodes a protocatechuate decarboxylase from Enterobacter cloacae (Vardon et al., 2016, Vardon et al., 2015). Catechol then undergoes intradiol ring cleavage by action of the CatA and CatA2 dioxygenases to form cis,cis-muconate, which accumulates due to deletion of catB and catC. Putative targets of Crc regulation are shown (Browne et al., 2010, Hernández-Arranz et al., 2013, Morales et al., 2004).