| Summary: | 碩士 === 明道大學 === 材料科學與工程學系碩士班 === 98 === Abstract
In the process of cellulosic ethanol production, the feedstock of cellulose should be transformed into mono-saccharides during hydrolysis. However, the ligno-cellulose, which is the main cellulosic components in biomass, has the chemically inert structure to prevent from hydrolysis. In order to raise the yield of mono-saccharides produced by hydrolysis of lingo-cellulose, it is required to collapse the structure of lingo-cellulose during some pretreatments. In this study, the culture bag waste produced from mushroom cultivation was used as the feedstock of cellulose. The lingo-cellulose components of culture bag waste were pretreated by the soaking solutions (0, 3, 5, 10, and 15%) of H2SO4, HCl, and NaOH, respectively. The times set for soaking in the H2SO4 and HCl solutions were 0.5, 1, 2, 4, and 8 hours. And, under soaking in the NaOH solutions, the times were set as 0.5, 1, 2, 4, and 8 days. Then, Scanning electron microscopy (SEM) was used to detect the surface structures of lingo-cellulose components in the pretreated culture bag waste. Hydrolysis of lingo-cellulose components was performed with the cellulase under 50oC water bathing for 24 hours. Reducing sugars in the hydrolysates were determined by the DNS method, and glucose and xylose were determined by using High performance liquid chromatography (HPLC). The yields of reducing sugars, glucose, and xylose were measured, and their relative hydrolysis rates were also calculated to be as the index for assessing the effects of the pretreatments on the hydrolysis of lingo-cellulose. The results of the present study showed that for the acid pretreatments, the soaking time of H2SO4 and the concentration of HCl were the main factors on the yields reducing sugars, glucose, and xylose. For the alkaline pretreatments, the soaking time and the concentration of NaOH significantly influenced the yields reducing sugars, glucose, and xylose. In addition, the ratio of mono-sacchrides to reducing sugars was relatively low under the H2SO4 treatments. This suggested that the pretreatment by the soaking solution of H2SO4 might be suitable for the traditional process of cellulosic ethanol production, called separate hydrolysis and fermentation (SHF). Compared with the H2SO4 treatments, the HCl and NaOH treatments promoted much higher yields of reducing sugars, glucose, and xylose. Thus, the pretreatment by the soaking solution of HCl and NaOH would be used for the novel process of cellulosic ethanol production, called simultaneous saccharification and fermentation (SSF).
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