重组多功能木聚糖酶酶解条件的优化  

Optimization of enzymatic hydrolysis of recombinant multi-functional xylanase

作　　者：赵力超[1] 王燕[1] 刘晓娟[1] 林俊芳[1] 

机构地区：[1]华南农业大学食品学院,广州510642

出　　处：《农业工程学报》2014年第1期270-277,共8页Transactions of the Chinese Society of Agricultural Engineering

基　　金：教育部博士点新教师项目(20114404120026);国家863项目(2006AA10Z301)

摘　　要：重组多功能木聚糖酶(recombinant multi-functional xylanase,RMFXase)是以草菇为表达载体,具有多种酶活力的新型酶。为揭示该酶与底物的作用规律,同时为转基因酶的应用提供基础数据,该文利用重组多功能木聚糖酶水解南方特色的甘蔗加工废弃物生产低聚木糖,通过响应面法建立以重组多功能木聚糖酶质量浓度、底物质量浓度和酶解时间为控制因素的反应动力学方程组,从而推导得到酶解最佳工艺参数。试验并通过高效液相色谱法法,监测反应过程中产物的动态变化,分析产物的生成规律。结果表明,通过响应面法推导出符合连续式酶解反应器的最佳酶解工艺参数为:加酶量900 U/mL、底物质量浓度110 mg/mL、反应时间80 min。该条件下酶解木聚糖含量为54.7%的蔗渣半纤维素,得到的低聚木糖DP值达到3,酶解率达到23.94%。酶解过程中重组多功能木聚糖酶表现出高内切-β-1,4-木聚糖活力,优先降解大分子木聚糖,后期产物主要以木二糖和木三糖为主,且底物纯度越高,底物利用率越高。The utilization of microorganisms or their enzymes may be the most promising method to produce Xylo-oligosaccharides （XOs） from agricultural wastes because of fewer undesirable by-products and fewer monosaccharides produced, and no special equipments required. Industrial-scale production of XOs using bioconversion requires low-cost substrates with a high xylan content, low lignin content and enzymes with high activity, process stability and β-1,4-xylosidic bond specificity. In the current study, bagasse, by-products of sugarcane production, was used as substrates for XOs production. And hydrolysis of bagasse hemicellulose was carried out with a recombinant multi-functional xylanase （RMFXase）. RMFXase is a novel enzyme produced from genetically engineered straw mushroom （Volvariella volvacea） strain, which has exo-β-1,4-glucanase, endo-β-1,4-glucanase, and endo-β-xylanase activities. After single factor experiments, including enzyme concentration, substrate concentration and hydrolysis time, the enzymatic hydrolysis kinetic model was established by response surface analysis. The evaluation indicators of the model involved reducing sugars concentration （RSC）, total soluble sugar concentration （TSC）, average degree of polymerization （DP） and hydrolysis rate （HR%）. The optimized design for continuous enzymatic hydrolysis reactor can be made from the model equation, and the yield of XOs can be predicted. Based on the kinetic model, the hydrolysis behavior of RMFXase was studied. The high-performance liquid chromatography （HPLC） method was used to analyze the end-products produced by RMFXase with oats pelts xylan, bagasse hemicellulose and bagasse separately. The results show that, for the continuous enzymatic hydrolysis reactor, the optimized conditions were enzyme concentration 900 U/mL, substrate concentration 110 mg/mL and reaction time 80 min. Under these conditions, after the bagasse hemicellulose which contained 54.7% xylan were hydrolyzed by RMFCase, the DP value of xylo-olig

关 键 词：食品 酶 动力学模型 重组多功能木聚糖酶 蔗渣 

分 类 号：TS209[轻工技术与工程—食品科学]