Direct Affinity-Immobilized Phenolic Acid Decarboxylase by a Linker Peptide on Zeolite for Efficient Bioconversion of Ferulic Acid into 4-Vinylguaiacol
Lulu Li, Liangkun Long, Shaojun Ding
Abstract
4-Vinylguaiacol (4-VG) is a promising aromatic compound widely used in food, cosmetic, pharmaceutical, and chemical industries. Developing a competitive and sustainable biosynthesis method for large-scale production of 4-VG is still a great challenge because of the toxicity of 4-VG and the precursor ferulic acid (FA). In this study, for the first time, 4-VG was efficiently produced from FA using linker-mediated immobilized phenolic acid decarboxylases from Bacillus atrophaeus (BaPAD) on Na–Y zeolite. We systematically investigated the effects of different lengths and positions of a linker peptide on its adsorption selectivity and affinity and BaPAD functionality. We found that the performance of 4LP-BaPAD was the most prominent, and its binding with Na–Y zeolite is highly stable, selective, and reversible. 4LP-BaPAD@Na–Y zeolite can be prepared by one-step purification and immobilization of enzymes on Na–Y zeolite directly from crude cell lysate. 4LP-BaPAD@Na–Y zeolite can be repeatedly used in an organic/aqueous biphasic system and still retained 73% of its original activity after 10 cycles of reuse. Ultimately, the titer and the productivity of 4-VG reached 295.8 g/L (1970 mM) and 22.8 g/(L h), respectively, using 4LP-BaPAD@Na–Y zeolite as the biocatalyst for converting FA into 4-VG in a bioreactor. These results highlight the great potential of this linker peptide for enzyme immobilization for biocatalysts used under biphasic organic/aqueous reaction conditions and the efficiency of the direct affinity-immobilized BaPAD for sustainable bioconversion of FA into 4-VG at the large-scale level.