Preparation of a novel laccase-modified Fe3O4/TiO2 catalyst for simultaneous delignification and saccharification of Spartina alterniflora Loisel.

The development of a cost-effective and environment-friendly conversion method to overcome the recalcitrance of biomass is a challenging task for enhancing the value-added potential of lignocellulosic compounds. In this study, a photo-enzyme composite catalyst by immobilizing laccase on Fe 3 O 4 /TiO 2 (denoted as LC-Fe 3 O 4 /TiO 2) was applied to the pretreatment and enzymatic saccharification of Spartina alterniflora Loisel (SAL) under the action of alternating light/dark cycles. The effect of the pretreatment temperature, pretreatment time, LC-Fe 3 O 4 /TiO 2 concentration, mass concentration of straw particles, and hydrolysis time on delignification efficiency and reducing sugar yield was investigated by a central composite design (CCD). Under the selected conditions (48 ℃, pretreatment time of 70 min, LC-Fe 3 O 4 /TiO 2 concentration of 4.9 mg/mL, mass concentration of straw particles of 22 % (w/v), hydrolysis time of 55 h), 92.53 % delignification and 129.85 mg/g reducing sugar yield were achieved. The enzymatic hydrolysis efficiency was higher compared to conventional methods. Moreover, the LC-Fe 3 O 4 /TiO 2 showed good recyclability and reusability. Developed LC-Fe 3 O 4 /TiO 2 particles have a high potential for use in biomass utilization. [Display omitted] • Laccase-Fe 3 O 4 /TiO 2 integrated catalyst (LC-Fe 3 O 4 /TiO 2) is first synthesized. • Effects of LC-Fe 3 O 4 /TiO 2 on pretreatment and saccharification is studied. • LC-Fe 3 O 4 /TiO 2 can enhance sugar yield under the alternation of light and dark. • LC-Fe 3 O 4 /TiO 2 could be efficiently reused up to 3 cycles. [ABSTRACT FROM AUTHOR]