Biocatalytic production of adipic acid from glucose using engineered Saccharomyces cerevisiae

Abstract

Adipic acid is an important industrial chemical used in the synthesis of nylon-6,6. The commercial synthesis of adipic acid uses petroleum-derived benzene and releases significant quantities of greenhouse gases. Biocatalytic production of adipic acid from renewable feedstocks could potentially reduce the environmental damage and eliminate the need for fossil fuel precursors. Recently, we have demonstrated the first enzymatic hydrogenation of muconic acid to adipic acid using microbial enoate reductases (ERs) - complex iron-sulfur and flavin containing enzymes. In this work, we successfully expressed the Bacillus coagulans ER in a Saccharomyces cerevisiae strain producing muconic acid and developed a three-stage fermentation process enabling the synthesis of adipic acid from glucose. The ability to express active ERs and significant acid tolerance of S. cerevisiae highlight the applicability of the developed yeast strain for the biocatalytic production of adipic acid from renewable feedstocks.

Advances in bio‐based production of dicarboxylic acids longer than C4

“…2H) [119,120]. The maximal titer of adipate was 27.6 mg/L in E. coli and 2.6 mg/L in S. cerevisiae [119,120].…”

“…However, the bioconversion of cis,cis-muconic acid to adipate used to be a main obstacle for direct synthesis of adipate from renewable sources using this pathway. The maximal titer of adipate was 27.6 mg/L in E. coli and 2.6 mg/L in S. cerevisiae [119,120]. 2H) [119,120].…”

“…Various P450 monoxygenases, oxidoreductases and esterases have been identified responsible for conversion of the terminal methyl to carboxyl group in carboxylic acids, and have been engineered with superior catalytic activity with an expanding substrate spectrum [18][19][20]. (A) ω-Oxidation, the ω-oxidation reactions converting the methyl group to a carboxylic group at the ω-position of carboxylic acids [17,19,20], FAS, fatty acid synthase; (B) AMV pathway, aminovalerate pathway started from L-lysine to yield glutarate [25][26][27][28], 2-KG, α-ketoglutarate, L-Glu, L-glutamate; (C) C+1 elongation, the C1 elongation pathway started from α-ketoglutarate (AKG) to yield α-ketoadipate (AKA) or α-ketopimelate (AKP) [29,30]; α-Keto decarboxylation and oxidation, the α-ketoacid decarboxylation pathway started from AKA or AKP to yield glutarate or adipate [31,32]; (D), α-Keto reduction, the α-ketoacid reduction pathway started from AKG to yield glutarate [34]; (E) Reversal β-oxidation, the reversal β-oxidation pathway started from the condensation of acetyl-CoA and acyl-CoA (C = n) to yield free fatty acid (C = n+2) [40][41][42][44][45][46]; (F) PKSs, engineered polyketide synthase (PKS)-based pathway started from the condensation of succinyl-CoA and malonyl-CoA to yield adipate [49]; (G) Biotin-fatty acid pathway, the engineered biotin synthetic pathway by removing the activity for biotin synthesis (BioH) and overexpression of specific thioesterase to yield odd-chain DCAs [51], SAM, S-adenosyl-L-methionine, SAH, S-adenosylhomocysteine; Muconic acid pathway, a extended muconic acid biosynthetic pathway converting cis, cis-muconic acid into adipate [119,120] . For example, an engineered pathway for the synthesis of medium chain carboxylic acids (C6-C10) was recently established ( Fig.…”

“…Recently, two enoate reductases from C. acetobutylicum and Bacillus coagulans were identified and expressed in E. coli and S. cerevisiae respectively, resulting the functional biocatalysis of cis,cis-muconic acid to adipate (Fig. 2H) [119,120]. The maximal titer of adipate was 27.6 mg/L in E. coli and 2.6 mg/L in S. cerevisiae [119,120].…”

Novel two-stage processes for optimal chemical production in microbes

“…Metabolic networks have a bow-tie architecture which allows a large number of metabolites to be produced from a few universal precursors 2 . This has allowed us to successfully engineer microbes to be biocatalysts for the production of a wide range of commodity chemicals 3,4 , pharmaceuticals 5,6 , biofuels, 7,8 and other natural and non-natural compounds 9 . While few such processes have been successful at an industrial scale 10,11 , large strain development costs and scale-up issues could deem many processes economically infeasible 12,13 .…”