A Coenzyme-Free Biocatalyst for the Value-Added Utilization of Lignin-Derived Aromatics

Abstract

Value-added utilization of lignin waste streams is vital to fully sustainable and economically viable biorefineries. However, deriving substantial value from its main constituents is seriously hindered by the constant requirement for expensive coenzymes. Herein, we devised a coenzyme-free biocatalyst that could transform lignin-derived aromatics into various attractive pharmaceutical and polymer building blocks. At the center of our strategy is the integrated use of new mining phenolic acid decarboxylase and aromatic dioxygenase with extremely high catalytic efficiency, which realizes the value-added utilization of lignin in a coenzyme-independent manner. Notably, a new temperature/pH-directed strategy was proposed to eliminate the highly redundant activities of endogenous alcohol dehydrogenases. The major components of lignin were simultaneously converted to vanillin and 4-vinylphenol. Since the versatile biocatalyst could efficiently convert many other renewable lignin-related aromatics to valuable chemicals, this green route paves the way for enhancing the entire efficiency of biorefineries.

Functional Autodisplay of Phenolic Acid Decarboxylase using a GDSL Autotransporter on Escherichia coli for Efficient Catalysis of 4-Hydroxycinnamic Acids to Vinylphenol Derivatives

“…It was also used as a precursor for the synthesis of bio-based polymers such as oxygenated polystyrenes [3,4]. Recently, it was reported that 4-VG could be efficiently biotransformed into vanillin by the carotenoid cleavage oxygenase family enzymes [5][6][7]. 4-Vinylphenol (4-VP, 4-hydroxystyrene) is a monomer for production of polymers and a petroleum-based feedstock for resins, elastomers, and adhesives [8,9].…”

Lignin valorization meets synthetic biology

“…Nevertheless, the biosynthetic route containing Fcs and Ech has seriously hindered the effective conversion of lignin‐derived aromatics due to constant requirement for ATP and CoA . In further, Pad and Ado, a coenzyme‐free pathway was introduced into E. coli to produce vanillin and 4‐vinylguaiacol from ferulic acid . Heterologous expression of VpVAN gene from Vanilla planifolia catalyzed lignin unit ferulic acid to vanillin in S. cerevisiae .…”

3D‐Printed Phenacrylate Decarboxylase Flow Reactors for the Chemoenzymatic Synthesis of 4‐Hydroxystilbene

“…[14] Furthermore, unlike other cofactor-dependent PADs, these enzymes do not require ap renylated flavin cofactor,w hich typically requires production by coexpression of the flavin prenyltransferase UbiX. [14,15] In a second step of the cascade, the enzymatically produced vinylphenols can then be furtherf unctionalized, for example, by aid of other enzymes, [16] oxidative dimerization [17] or by organometallic coupling reactions [18] as demonstrated here.…”