Hydroxytyrosol production from l-DOPA by engineered Escherichia coli co-expressing l-amino acid deaminase, α-keto acid decarboxylase, aldehyde reductase and glucose dehydrogenase with NADH regeneration

Abstract

Hydroxytyrosol, a phenolic compound derived from olives, is conducive to human health and is widely used in food additives and cosmetic industries due to its significant antioxidant activity and cancer prevention properties. In this research, we designed and constructed a nearly irreversible and efficient bio-catalysis cascade reaction for hydroxytyrosol production from L-3,4-dihydroxy-phenylalanine. The recombinant Escherichia coli cells were constructed by co-expressing L-amino acid deaminase from Cosenzaea myxofaciens, α-keto acid decarboxylase from Proteus mirabilis, aldehyde reductase from Escherichia coli (DE3) and glucose dehydrogenase from Bacillus subtilis. The glucose dehydrogenase catalyzed the dehydrogenation of co-substrate (glucose) to achieve the regeneration of NADH, which was an indispensable reductant for producing hydroxytyrosol. Subsequently, the expression of these enzymes was coordinated using a strategy of combining two different compatible plasmids. Finally, the production of hydroxytyrosol reached at 55.53 mM (8.55 g/L) within 6 h under the optimum biotransformation conditions.