PHYSICAL PROCESSES IMPROVE ENZYMATIC HYDROLYSIS OF CORN STOVER

摘要

Mild chemical pretreatment combined with physical pretreatments for the enzymatic hydrolysis of com stover was studied. The ground corn stover with different particle sizes were soaked in the 0.1N-1N NaOH solution for 2 hours at room temperature usinga solid:liquid ratio of 0.lg/ml. After washing, the pretreated ground corn stover was dis-persed uniformly in water. The effect of dispersing, cellulase loading (20 to 100 GCU/g solid), alkaline concentration (0.1 to l.0N), and particle sizes (2mm, 25 mesh, and 60mesh) on the saccharification rate of the corn stover samples were studied. It was found that increasing the cellulase loading from 20 to 100 GCU/g solid raised the hydrolysis rate of corn stover by only 13%. Reducing the product size (from 2mm to 60 mesh) through grinding before NaOH treatment resulted in only minimal increases in the enzymatic cellulose conversions, while the dispersing process after NaOH soaking in-creased the hydrolysis rate by as much as 40%. The hydrolysis rate of dispersed sample pretreated with 0.2-0.3N alkaline is close to that of the traditional ground sample pretreated with 1.0 N alkaline. The lower the concentration of alkaline was, the higher the effect of dispersing process. It seems that the dispersing processnot only reduces the particle size, but also makes the material more accessible to the cellulase.