LAUSR

The production of high-value phenolic acids is of significant importance for sustainability in the pharmaceutical industry. In this study, an artificial thermophilic reaction cascade composed of D-mandelate dehydrogenase (ManDH), phenylalanine 4-hydroxylase (PAH), and hydroxyphenylacetate 3-hydroxylase (HpaH) was constructed to utilize the low-cost phenylpyruvic acid (PPA) and 2-phenylglyoxylic acid (PGA) as dual substrates. The dihydroxyphenolic acids salvianic acid A (SAA) and 3,4-dihydroxymandelic acid (DOMA) were then produced at 84.9% and 90.9% of the theoretical yields from PPA and PGA, respectively. The key to success of the reaction was the novel TbManDH from Thermococcus barophilus and TcPAH from Thermomonospora curvata that exhibited a broad substrate specificity. The newly in situ regeneration of the cofactor 6,7-dimethyl-5,6,7,8-tetrahydropterine (DMPH4) in combination with nicotinamide adenine dinucleotide (NADH) recycling also contributed to the high production yields. Considering the broad ...