Biosynthesis of 4-vinylguaiacol from crude ferulic acid by Bacillus licheniformis DLF-17056

•Crude ferulic acid was obtained from rice bran residue after protein extraction.•No purification of ferulic acid was required in biosynthesis of 4-vinylguaiacol.•Bacillus licheniformis DLF-17056 exhibited excellent catalytic activity. 4-vinylguaiacol, a kind of volatile phenolic compound with tobacco flavor, is widely used as a component of edible flavor and intermediate of medicine. Ferulic acid is usually used as substrate for the biosynthesis of 4-vinylguaiacol. However, the price of ferulic acid is high, leading to high production cost. In this study, a feasible low-cost process for the production of 4-vinylguaiacol was developed. The ultrasonic assisted weak alkali was used to extract protein from rice bran, and waste liquid and residue were then mixed to extract crude ferulic acid by alkaline hydrolysis. Subsequently crude ferulic acid without further purification was directly converted into 4-vinylguaiacol via alginate-immo cells of the strain Bacillus licheniformis DLF-17056, which was newly isolated and highly active with ferulic acid conversion to 4-vinylguaiacol. 4-Vinylguaiacol could be produced up to 0.76 g/L from 1.0 g/L ferulic acid within 24 h biotransformation. Furthermore, the immobilized biocatalysts retained above 60% initial activity even after 8 times biotransformations. Thereby, it was assumed that our study would contribute to the industrial production of 4-vinylguaiacol from ferulic acid.