Efficient production of 5-hydroxymethylfurfural from hexoses using solid acid SO_4^(2-)/In_2O_3-ATP in a biphasic system

A natural attapulgite （ATP）‐based catalyst, sulfated In2O3‐ATP （SO42-/In2O3‐ATP）, was obtained by an impregnation‐calcination method and was used to efficiently and selectively produce the useful platform chemical 5‐hydroxymethylfurfural （HMF） from hexoses. Some important reaction param‐eters were studied, revealing that Lewis and Br-nsted acid sites on SO42-/In2O3‐ATP catalyze glu‐cose isomerization and fructose dehydration. The yields of HMF from glucose and fructose were 40.2%and 46.2%, respectively, using the optimal conditions of 180℃ for 60 min with 10 wt%of solid acid catalyst in a mixture of γ‐valerolactone‐water （9：1）.

Glucose Isomerization into Fructose Catalyzed by MgO/NaY Catalyst

The MgO/NaY catalysts prepared by impregnation method were used for the conversion of glucose to fructose in water medium. The effects of MgO loading, reaction temperature, glucose concentration and reaction time on the catalytic performance for the reaction were studied. The activity testing results indicated that fructose could be generated effectively by controlling the components of the catalyst and reaction conditions. The maximal fructose yield of 33.8% with the selectivity of 67.3% was achieved over the 10%MgO/NaY catalyst at 100 ℃ for 2 h. Moreover, the catalysts were characterized by XRD, BET, and CO2-TPD techniques. The structural property of NaY with higher surface area facilitated glucose conversion, and the modulated basicity of the catalyst with MgO addition contributed to the formation of fructose in the tautornerization of aldose to ketose.

Preparation of Sn-β-zeolite via immobilization of Sn/choline chloride complex for glucose-fructose isomerization reaction

Well dispersion of tin species in an isolated form is a quite challenge since tin salts are easily hydrolyzed into（hydr）oxides during aqueous stannation of β-zeolite.In this study,immobilization of tin species on high silica commercial β-zeolite by using SnCl_2/Choline chloride（ChCl） complex followed with calcination provided a convenient way to get well dispersed Sn in β-zeolite in the aqueous condition,which was observed based on electron microscopy images,UV visible spectra and X-ray diffraction pattern.The existence of ChCl facilitated tin species to incorporate into zeolite.（1-2）wt%of Sn loaded β-zeolites exhibited good catalytic activity and high selectivity for glucose-fructose isomerization reaction.

塔格糖-4-异构酶的新酶挖掘及酶学性质研究

D-塔格糖是一种己酮糖,在自然界中天然存在但含量极少,具有降血糖、抗龋齿、改善肠道菌群、促进血液循环和抗衰等作用,可广泛应用于食品、医药和化妆品行业。目前酶催化半乳糖生成塔格糖仅需一步反应,简单易行,但半乳糖较高的成本限制了这一方法的工业应用。果糖是塔格糖的同分异构体,价格低廉,来源稳定,可通过4位差向异构化一步获得塔格糖,是产塔格糖的理想底物。【目的】因此挖掘新的塔格糖-4-差向异构酶对塔格糖的工业生产具有重要意义。【方法】本文通过基因挖掘的手段发现了热袍菌(Thermotogae bacterium)来源的未知功能蛋白(命名为HCZ0)具有塔格糖-4-差向异构酶活性,进而完成了HCZ0的异源表达、纯化及酶学性质表征。【结果】确定HCZ0表观分子量约为57.9kDa,比活力为0.9U/mg,最适反应温度和pH值分别为70°C和9.0,最适金属离子为Ni2+,最适金属离子浓度为2mmol/L,60、70和80℃半衰期分别为180、67和9 h。最适条件下,HCZ0催化200 g/L果糖在2 h内可产生28 g/L塔格糖。【结论】本研究中,HCZ0是碱性高温酶,且具有较好的热稳定性,这些特征在以后的理论研究及工业生产中具有一定的科学价值。