关键词: 高酸值废弃油脂, 预酯化, 制备, 生物柴油, 放大

Abstract: To improve the enzymatic saccharification of lignocellulosic biomass, ethylene glycol assisted with hydrochloric acid was used for pretreating hickory shell in this study. After the optimization in oil-bath system, the optimal pretreatment condition was obtained as following:the pretreatment media was hydrochloric acid-ethylene glycol-water (1.2%:88.8%:10%, mass ratio), pretreatment temperature 130℃, and pretreatment time 30min. In order to reduce the pretreatment temperature and time, microwave radiation was employed to assist the pretreatment with hydrochloric acid-ethylene glycol-water (1.2%:88.8%:10%, mass ratio) media, and the optimal pretreatment condition was achieved as following:microwave radiation temperature 100℃, microwave radiation time 5min, and microwave radiation power 200W. These results showed that the saccharification rate of pretreated hickory shell was higher than that of untreated one. After the pretreatment with oil-bath and microwave radiation, the reducing sugar yield from the enzymatic hydrolysis could reach 88.6% (oil bath) and 74.2% (microwave) after 72h. By using electron microscopy (SEM) and infrared spectroscopy (FT-IR) analysis, the structure of pretreated hickory shell was destroyed, the structure became loose, and porous were easier to be enzymatically hydrolyzed, which increased the enzyme accessibility, thereby greatly improving the saccharification rate. Therefore, the pretreatment with hydrochloric acid-ethylene glycol-water solution can improve the efficiency of the enzymatic saccharification of hickory shell.

Key words: waste oil with high acid value, pre-esterification, preparation, biodiesel, scale-up