Two-stage acid hydrolysis of soyresidue to produce glucose and xylose

[[abstract]]亞洲國家與美國每年產生約1300萬公噸豆渣，其中含有150-200萬公噸纖維素，多數尚未回收利用。如能先將纖維素經水解、發酵等步驟轉化為酒精，不僅可解決廢棄物處理問題，且可回收有用能源。 本研究除探討以二階段酸性水解方式，將豆渣轉化為還原醣的技術可行性外，並探討濃度、溫度及反應時間等三因子對轉化率的影響。首先應用實驗設計法決定實驗條件與取得所需數據，然後應用多變量迴歸法，建立二次方程式；最後再以牛頓法求得最適反應條件。 實驗結果發現，每公克豆渣（乾基）可產生478毫克還原醣，其中222毫克木糖、78毫克葡萄糖為單糖，可作為纖維酒精原料。第一階段還原醣最佳轉化率為403 mg/g，最佳條件為6％硫酸濃度、120℃溫度、90分鐘反應時間；第二階段最佳轉化率為252 mg/g，最佳條件為16％硫酸濃度、150℃溫度、90分鐘反應時間。本研究確認豆渣可經二次水酸水解方式以產生生質酒精的基本原料－葡萄糖與木糖。[[abstract]]Each year Asian nations and the United States generate more than 13 million tons of soy residue from productions of tofu and soymilk Soy residue contains 50-55% cellulose and 15-20% of fats that can be converted into biofuels but the majority of soy residue was sent to landfills and composting facilities This work was to explore the possibility of using a two-stage acid hydrolysis to convert soy residue into reducing sugars and to study the effects of acid concentration reaction temperature and time on the conversion In each stage of acid hydrolysis a central composite design method was used for the selection of experimental conditions and a multivariate regression analysis was applied to fit the data into quadratic polynomial Experimental results showed that each gram of soy residue could produce 478 milligrams of reducing sugars including 222 mg of xylose and 79 mg of gluclose in the first stage of acid hydrolysis the optimal sugar yield was 403 mg/g when the acid concentration temperature and reaction time were 6% 120℃ and 90 minutes respectively Only 30% of solid soy residue was unreacted In the second stage the optimal sugar yield was 252 mg/g when the acid concentration reaction temperature and time were 16% 150 ℃ and 60 minutes respectively This work demonstrated that soy residue could be used as a raw material for the production of glucose and xylose which could be fermented into alcohol