폐 신문지의 효소당화율을 향상시키기 위한 암모니나 전처리 방법
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The ethanol is intended to be used as a substitute for fossil liquid fuels, such as gasoline. Ethanol from biomass has the advantage of being produced from a renewable resource. The ethanol could be produced from corn stover/cobs, yellow poplar, sugarcane bagasse, straws, switch grass, waste lumbers and waste paper, etc. There is, however, no abundant resources except for wastepapers in Korea. Wastepaper constitutes half of municipal solid waste. Effective pretreatment is needed to increase enzymatic hydrolysis of newspaper. A pretreatment method suitable for wastepaper must be developed since paper has already had considerable physical and/or chemical treatment, and contains ink, fillers, and other additives. Newspaper was pretreated with ammonia solution on a shaking water bath at 40℃ using 130 strokes/min for 3h. This study shows two different pretreatment methods for wastepaper, one is treated with ammonia, hydrogen peroxide, and the other with ammonia and surfactant. In the first method, ammonia was used in combination with hydrogen peroxide and nonionic surfactant. Nonionic surfactants, NP series and TW series, were utilized. The effect of the surfactant loading on digestibility was small below 0.5 wt%. The effect of the HLB value of both series surfactants on digestibility was found to be negligible, even though ink removal was improved as the HLB value was increased. Digestibility of the NP-5-added sample relative to control sample, increased significantly at lower enzyme loading. According to this results, a small amount of NP-5 could significantly reduce enzyme loading. It was also found that ink removal before enzymatic hydrolysis is very important to enhance digestibility. In the second method, the recycled newspapers were pretreated with ammonia solution and NP-5 without hydrogen peroxide. Digestibility achieved by the treatment with ammonia and NP-5 was the same as the simultaneous treatment with ammonia, hydrogen peroxide, and NP-5, which means that hydrogen peroxide does not need if surfactant is added in ammonia solution. In the ammonia and NP-5 treatment, the effect of NP-5 loading on digestibility was negligible so that 0.5 wt% was selected. Digestibility decreased a little if HLB value increased. Also, it was found that surfactant addition in pretreatment stage was a little more effective on cellulose hydrolysis than surfactant addition in enzymatic hydrolysis.