Enzymatic Hydrolysis and Physiochemical Characterization of Corn Leaf after H-AFEX Pretreatment
2016
Zhao, Chao | Ma, Zhongqing | Shao, Qianjun | Li, Bin | Ye, Jiewang | Peng, Hehuan
Hydrogen peroxide presoaking prior to ammonia fiber expansion (H-AFEX) was applied to enhance fermentable sugars production from corn leaf. Effects of temperature and H₂O₂ loading on solid recovery, chemical constitution, and polysaccharide conversion were investigated. Physiochemical characterizations of raw material and H-AFEX-treated substrates were obtained using digital microscopy, X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). The results showed that the H-AFEX process was an effective pretreatment for improving enzymatic hydrolysis of corn leaf. The H-AFEX-treated substrates under optimal conditions following enzymatic hydrolysis achieved 91.6% glucan conversion, 80.6% xylan conversion, and a total monosaccharide yield of 411.8 g per 1000 g dry biomass. Further studies showed that the H-AFEX process induced morphological modification of corn leaf by removing minerals/extractives, relocating melted lignin, and generating pores. XRD data revealed that the crystallinity index of H-AFEX-treated substrate decreased. The disruption of crystalline structure, the removal of amorphous substances, and the transition of crystalline region to amorphous region were observed. FTIR data demonstrated that H-AFEX pretreatment disrupted hydrogen bonds inter-/intra-cellulose chains, altered the supramolecular structure of cellulose, and caused destruction to the molecular structure of residual lignin. As a result, the H-AFEX process significantly reduced the recalcitrance of corn leaf and facilitated biomass conversion to fermentable sugars.
显示更多 [+] 显示较少 [-]