重组褐藻胶裂解酶酶解工艺的优化及产物分析

为探索假交替单胞菌（Pseudomonas syringae）重组褐藻胶裂解酶降解褐藻胶的动态过程变化，采用DNS法和苯酚－硫酸法分别测定体系还原糖和总糖，根据二者比例，得出酶解产物随时间变化的平均聚合度，从而研究各因素对褐藻胶降解过程的影响，确定褐藻胶酶解工艺条件。结果表明，重组褐藻胶裂解酶降解褐藻胶的适宜工艺条件为:水解温度25 ℃，pH 7.5，初始底物质量浓度7 g/L，加酶量0.48 U，静置条件下酶解反应210 min。在此工艺条件下，产生的还原糖的质量浓度达0.878 g/L，平均聚合度为3。酶解终产物的质谱鉴定结果显示为单糖、二糖和四糖。

Optimization of the Enzymatic Process and Analysis of the Hydrolysates by the Recombinant Alginate Lyase

The aim of the study is to determine the dynamic process and technical conditions of alginate degradation by the recombinant alginate lyase from Pseudomonas syringae.The contents of the reducing sugar and the total polysaccharide were determined by 3,5-dinitrosalicylic acid assay and phenol-sulfuric acid method,respectively.According to the ratio of reducing sugar and total sugar,the variation regularity of average polymeric degree of the enzymatic hydrolysates were obtained.The influence factors in the enzymatic process were studied,and the optimal conditions for alginate degradation by the recombinant alginate lyase were determined.The results showed that optimal conditions for enzymatic hydrolysis were:temperature 25 ℃,pH 7.5,initial substrate concentration 7 g/L,enzyme 0.48 U,and reaction time 210 min.Under these condition,the concentration of reducing sugar reached 0878 g/L and the average polymetric degree fell to 3.The enzymatic hydrolysates were identified by mass spectrometer and the final products mainly included monosaccharide,disaccharide and tetrasaccharide.