Fig. 9: Metabolic pathway and cultivation.
From: Catalytic carbon–carbon bond cleavage in lignin via manganese–zirconium-mediated autoxidation
A Metabolic pathway for the production of muconate from oxidation streams of methylated pine RCF in P. putida strain ACB263. Strain ACB263 is derived from another muconate-producing strain, CJ78151, and modifications are indicated by purple boxes/arrows. Aldehyde dehydrogenase(s) (ALDH) catalyze the oxidation of veratraldehyde to veratrate, which then undergoes p-demethylation to vanillate by the CYP199A4 system. VanAB O-demethylates vanillate to protocatechuate, which is decarboxylated to catechol by the AroYE474V-EcdBD system, followed by ring cleavage to produce muconate. Undesirable accumulation of isovanillate was prevented by the isovanillate demethylase, IvaAB. Diversion of metabolites to growth was avoided by deletion of catRBC and pcaHG. B Cultivation of strain ACB263 in M9 + 2 mM veratraldehyde produces the equivalent molar yield of muconate. C Cultivation of strain ACB263 in M9 + 2 mM veratrate produces the equivalent molar yield of muconate. D Strain ACB263 produces muconate from veratrate and veratraldehyde when grown in M9 + 10% v/v oxidation products from methylated pine RCF (representative plot from one oxidation reaction; two additional preparations are shown in Supplementary Fig. 39). Catechol and isovanillate were not detected in any of the culture supernatants. Error bars indicate the standard deviation from the mean of three biological replicates (error bars are smaller than the size of the marker in most cases; see numerical data for this fig. in Supplementary Table 22).
