Sustainable extraction of ferulic acid and p-coumaric acid from corn husk via autohydrolysis and enzymatic hydrolysis

Abstract

Corn husk, a by-product of corn processing, is often used as animal feed or returned to the soil. However, it is rich in phenolic acids such as ferulic acid (FA) and p-coumaric acid (pCA), making it a promising feedstock for high-value compound extraction. In this study, an innovative two-stage process combining autohydrolysis and dual-enzyme hydrolysis (recombinant xylanase McXyn0243 and feruloyl esterase BpFae03105ᴳ¹²³ᴬ) was developed and optimized for FA and pCA production. The optimal conditions were identified as follows: corn husk (20–40 mesh) treated at 158.7 °C for 41 min with a solid-liquid ratio of 1:23.6, followed by enzymatic hydrolysis at 47.2 °C, pH 5.5, 120 rpm for 2.57 h, using BpFae03105ᴳ¹²³ᴬ (0.67 U/mL), McXyn0243 (6.7 U/mL), and 1 g/L of Triton X-100. Under these conditions, the yield of FA increased to 54.0 % (4.84 g/kg corn husk), a 1.6-fold improvement, while pCA yield reached 40.0 % (5.44 g/kg corn husk), reflecting a 1.7-fold enhancement. Additionally, 109.7 mg/g of xylooligosaccharides was produced. These findings demonstrate that combining autohydrolysis with dual-enzyme hydrolysis offers an efficient and environmentally friendly strategy for the sustainable valorization of corn husk into high-value bio-based products.