鲜浒苔稀硫酸水解产糖工艺研究

The study of dilute sulfuric acid hydrolysis process of fresh Ulva prolifera for reducing sugars yield

分别用质量分数为0.6%、1.0%、1.4%、1.8%、2.2%的稀硫酸在121℃高温高压的条件下水解鲜浒苔30、60、90 min,浒苔水解残留物再用纤维素酶酶解,用DNS法测定上述各步骤中的还原糖产量。结果表明,浒苔总糖含量为67.2%。稀硫酸水解工艺中,硫酸质量分数为1.8%、水解90 min,浒苔还原糖转化率最高,达59.9%,每克干质量浒苔可产生447.0 mg还原糖。稀硫酸水解残留物纤维素酶酶解工艺中,浒苔还原糖转化率较低,在硫酸质量分数为0.6%、水解时间为60 min时还原糖转化率出现最大值,仅为6.5%。结果显示浒苔稀硫酸水解产还原糖效果显著,但并不能促进纤维素酶酶解。浒苔糖化可单独采用稀硫酸水解工艺,本实验条件下的最佳工艺条件为1.8%硫酸水解90 min。本研究探索了浒苔糖化工艺条件,对后续的浒苔燃料乙醇发酵研究具有一定的参考意义。

Based on the improved two-stage sulfuric acid hydrolysis method, the total sugar content of Ulva prolif- era was determined as 67.2%. The samples of fresh U. prolifera were mixed with gradient dilute sulfuric acid （0.6, 1.0, 1.4, 1.8, 2.2%（w/w） ） and hydrolyzed at 121°C with reaction time of 30, 60 and 90 rain, the solid U. prolifera residues recovered after sulfuric acid hydrolysis were hydrolyzed by cellulases, the yield of the reducing sugars from each step was determined by DNS method. It was showed that in the process of acid hydrolysis, the highest conversion rate of reducing sugars was obtained as 59.9% when the concentration of the sulfuric acid was 1.8% and the hydrolyzing time was 90 min, the yield of reducing sugars was 447.0 mg every 1000 mg dry sample. However, in the process of enzymatic hydrolysis, the conversion rate of reducing sugars from residue was low, the maxium value was only 6.5% when the concentration of sulfuric acid was 0.6% and the hydrolyzing time was 60 min. It was revealed that the acid hydrolysis was effective to hydrolyze U. prolifera sugars independently, and the optimized condition in this experiment was 1.8%（w/w） sulfuric acid with 90 min of hydrolyzing time, this will imorove the further research on transferring the U. prolifera as a potential material to produce fuel ethanol.