Alternative Routes for the Production of Natural 4-Vinylguaiacol from Sugar Beet Fiber Using Basidiomycetous Enzymes

oleh: Thorben Günther, Lasse Schoppe, Franziska Ersoy, Ralf G. Berger

Format: Article
Diterbitkan: MDPI AG 2021-05-01

Deskripsi

Traditional smoking generates not only the impact flavor compound 4-vinylguaiacol, but concurrently many unwanted and potent toxic compounds such as polycyclic aromatic hydrocarbons. Enzyme technology provides a solution without any side-product formation. A feruloyl esterase from <i>Rhizoctonia solani</i> (RspCAE) liberated ferulic acid from low-priced sugar beet fiber. Decarboxylation of ferulic acid to 4-vinylguaiacol was achieved by a second enzyme from <i>Schizophyllum commune</i> (ScoFAD). Both enzymes were covalently immobilized on agarose to enable reusability in a fixed-bed approach. The two enzyme cascades showed high conversion rates with yields of 0.8 and 0.95, respectively, and retained activity for nearly 80 h of continuous operation. The overall productivity of the model process with bed volumes of 300 µL and a substrate flow rate of 0.25 mL min<sup>−1</sup> was 3.98 mg 4-vinylguaiacol per hour. A cold online solid phase extraction using XAD4 was integrated into the bioprocess and provided high recovery rates during multiple elution steps. Attempting to facilitate the bioprocess, a fused gene coding for the two enzymes and a set of different linker lengths and properties was constructed and introduced into <i>Komagataella phaffii</i>. Longer and rigid linkers resulted in higher activity of the fusion protein with a maximum of 67 U L<sup>−1</sup>.