An alkaline active feruloyl-CoA synthetase from soil metagenome as a potential key enzyme for lignin valorization strategies

Abstract

Ferulic acid (FA), a low-molecular weight aromatic compound derived from lignin, represents a high-value molecule, used for applications in the cosmetic and pharmaceutical industries. FA can be further enzymatically converted in other commercially interesting molecules, such as vanillin and bioplastics. In several organisms, these transformations often start with a common step of FA activation via CoA-thioesterification, catalyzed by feruloyl-CoA synthetases (Fcs). In this context, these enzymes are of biotechnological interest for conversion of lignin-derived FA into high value chemicals. In this study, we describe the first structural characterization of a prokaryotic Fcs, named FCS1, isolated from a lignin-degrading microbial consortium. The FCS1 optimum pH and temperature were 9 and 37°C, respectively, with Km of 0.12 mM and Vmax of 36.82 U/mg. The circular dichroism spectra indicated a notable secondary structure stability at alkaline pH values and high temperatures. This secondary structure stability corroborates the activity data, which remains high until pH 9. The Small Angle X-Ray Scattering analyses resulted on the tertiary/quaternary structure and the low-resolution envelope in solution of FCS1, which was modeled as a homodimer using the hyperthermophilic nucleoside diphosphate-forming acetyl-CoA synthetase from Candidatus Korachaeum cryptofilum . This study contributes to the field of research by establishing the first biophysical and structural characterization for Fcs, and our data may be used for comparison against novel enzymes of this class that to be studied in the future.

Engineering a Feruloyl–Coenzyme A Synthase for Bioconversion of Phenylpropanoid Acids into High-Value Aromatic Aldehydes

“…Although the structure of FCS has been resolved in a previous study, FCS functional domains were not well defined. 49 This brought a great challenge for FCS enzyme engineering. In fact, FCS belongs to the superfamily of acyl−CoA ligase.…”

“…This might be because the catalytic pocket of wild-type FCS could not fit phenylpropanoid acids. Although the structure of FCS has been resolved in a previous study, FCS functional domains were not well defined . This brought a great challenge for FCS enzyme engineering.…”

Integrative omics analyses of the ligninolytic Rhodosporidium fluviale LM-2 disclose catabolic pathways for biobased chemical production

“…The biocatalytic conversion of ferulic acid can be useful for the production of desired chemicals [ 46 , 54 , 55 ]. Ferulic acid is usually converted to vanillin by FCS and FCHL with ATP consumption in two steps [ 56 , 57 ]: (i) CoA-thioesterification of ferulic acid by FCS, and (ii) hydration of feruloyl-CoA by FCHL. The alternative catabolic route of ferulic acid through the 4-VG pathway is a detoxification process involving non-oxidative decarboxylation driven by the cofactor-free enzyme PDC [ 20 ].…”