A Novel Biosynthetic Pathway for the Production of Acrylic Acid through β-Alanine Route in .

Acrylic acid (AA) is an important industrial chemical used for several applications including superabsorbent polymers and acrylate esters. Here, we report the development of a new biosynthetic pathway for the production of AA from glucose in metabolically engineered through the β-alanine (BA) route. The AA production pathway was partitioned into two modules: an AA forming downstream pathway and a BA forming upstream pathway. We first validated the operation of the downstream pathway and , and then constructed the downstream pathway by introducing efficient enzymes (Act, Acl2, and YciA) screened out of various microbial sources and optimizing the expression levels. For the direct fermentative production of AA from glucose, the downstream pathway was introduced into the BA producing strain. The resulting strain could successfully produce AA from glucose in flask cultivation. AA production was further enhanced by expressing the upstream genes ( and ) under the constitutive BBa_J23100 promoter. Replacement of the native promoter of the gene with the BBa_J23100 promoter in the genome increased AA production to 55.7 mg/L in flask. Fed-batch fermentation of the final engineered strain allowed production of 237 mg/L of AA in 57.5 h, representing the highest AA titer reported to date.