Chemicals effect on the enzymatic digestibility of rape straw over the thermo-mechanical pretreatment using a continuous twin screw-driven reactor (CTSR)

[Display omitted] ► Pretreatment of straw was conducted using a continuous twin screw-driven reactor. ► Mechanical pretreatment with hot water showed normal distribution of particle size. ► Size reduction by CTSR effectively promoted the enzymatic hydrolysis. ► CTSR pretreatment with chemical is effective on dissolving the non-cellulosics. Rape straw pretreated by a continuous twin screw-driven reactor (CTSR) with hot water presented a distinctive particle-size distribution profile as a function of the operating temperature. The relative amount of finer particle size dramatically increased as the ratio of solid to liquid was increased. Size reduction through physical CTSR process effectively promoted the enzymatic hydrolysis of pretreated rape straw. Meanwhile, the crystallinity of the physically pretreated straw was not a greater factor affecting the enzyme digestibility. The glucose conversion from the enzymatic hydrolysis of the straw pretreated by CTSR with hot water was maximized at 52%. Using the chemicals as catalyst have affected considerably for increasing the digestibility at same condition with hot water pretreatment. The enzymatic digestibilities of the straw pretreated by CTSR with sodium hydroxide and sulfuric acid were 60% and 77%, respectively.