Production of Salvianic Acid A from l-DOPA via Biocatalytic Cascade Reactions

Salvianic acid A (SAA), as the main bioactive component of the traditional Chinese herbSalvia miltiorrhiza, has important application value in the treatment of cardiovascular diseases. In this study, a two-step bioprocess for the preparation of SAA froml-DOPA was developed. In the first step,l-DOPA was transformed to 3,4-dihydroxyphenylalanine (DHPPA) using engineeredEscherichia colicells expressing membrane-bound L-amino acid deaminase fromProteus vulgaris.After that, the unpurified DHPPA was directly converted into SAA by permeabilized recombinantE. colicells co-expressingd-lactate dehydrogenase fromPediococcus acidilacticiand formate dehydrogenase fromMycobacterium vaccaeN10. Under optimized conditions, 48.3 mM of SAA could be prepared from 50 mM ofl-DOPA, with a yield of 96.6%. Therefore, the bioprocess developed here was not only environmentally friendly, but also exhibited excellent production efficiency and, thus, is promising for industrial SAA production.Keywords:salvianic acid A;l-DOPA;membrane-boundl-amino acid deaminases;biocatalysis;molecular biology;biological engineering