Junping Zhuang

Clean conversion of cellulose into fermentable glucose

We studied the process of conversion of microcrystalline-cellulose into fermentable glucose in the formic acid reaction system using cross polarization/magic angle spinning (13)C-nuclear magnetic resonance, X-ray diffraction and Fourier transform infrared spectroscopy. The results indicated that formic acid as an active agent was able to effectively penetrate into the interior space of the cellulose molecules, thus collapsing the rigid crystalline structure and allowing hydrolysis to occur easily in the amorphous zone as well as in the crystalline zone. The microcrystalline-cellulose was hydrolyzed using formic acid and 4% hydrochloric acid under mild conditions. The effects of hydrochloric acid concentration, the ratio of solid to liquid, temperature (55-75 degrees C) and retention time (0-9 h), and the concentration of glucose were analyzed. The hydrolysis velocities of microcrystalline-cellulose were 6.14 x 10(-3) h(-1) at 55 degrees C, 2.94 x 10(-2) h(-1) at 65 degrees C, and 6.84x10(-2) h(-1) at 75 degrees C. The degradation velocities of glucose were 0.01 h(-1) at 55 degrees C, 0.14 h(-1) at 65 degrees C, 0.34 h(-1) at 75 degrees C. The activation energy of microcrystalline-cellulose hydrolysis was 105.61 kJ/mol, and the activation energy of glucose degradation was 131.37 kJ/mol.

Efficient enzymatic hydrolysis of the bagasse pulp prepared with active oxygen and MgO-based solid alkali

The enzymatic hydrolysis of the bagasse pulp prepared from the treatment process with active oxygen and MgO-based solid alkali was studied. The hydrolysates were tested by IC (ionic chromatography) for the analysis of monosaccharide. Additionally, the changes of pulp before and after hydrolysis were characterized with Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD), Kajaani cellulose automatic analyzer and atomic force microscopy (AFM) techniques. The results showed that an optimized sugar yield of 82.38% was obtained at the substrate concentration of 5% for 72h with the enzyme dosage of 15IU/g. Furthermore, as the length of the cellulose fiber decreased, the crystallinity of cellulose increased, and more depressions appeared on the surface of pulp after enzymatic hydrolysis.

Detoxification of Wheat Straw Hydrolysis in Formic Acid Reaction System by D311 Ion-exchange Resin

Formic acid hydrolysis is widely used in lignocellulose pretreatment. However, formic acid hydrolysis wheat straw cannot be directly used as a fermentation substrate owing to various fermentation inhibitors, especially the formic acid in reaction system and released during pretreatment. Study found treatment of wheat straw hydrolysate with D311 ion-exchange resin had a good result on reduction formic acid. We investigated the influence of D311 resin content on the elimination of residual formic acid and the adsorbance of glucose. The results reveal that 22.5 g D311 resin can eliminate 94% of residual formic acid and with only 15% reducion of glucose concentration.

Catalytic Conversion of Glucose to 5-hydroxymethylfurfural over Aluminum Acetylacetonate in the Two-phase Water-Methylisobutylketone System

5-hydroxymethylfurfural (5-HMF) is a kind of new green platform chemical with wide application. Glucose, which is the unit compound of cellulose, is one of the most important starting chemicals from biomass. With its low cost and wide supply, the conversion of glucose to HMF has attracted the interests of researchers. In this work, a systematic study has been conducted to evaluate the effects of operating conditions on glucose conversion to to 5-HMF using Al(acac)3 catalyst in water-4-Methyl-2-pentanone two-phase system. The results showd that the conversion rate and the selectivity of glucose to 5-HMF with Al(acac)3 as catalyst were higher than those with AlCl3, CrCl3, Zr3(PO4)4, MCM-41 molecular sieves and 732 Cation Exchange Resin, so Al(acac)3 catalyst was selected for further studies. The optimum preparation conditions of 5- HMF catalyzed by Al(acac)3 were as follows: temperature at 180 ¿, dosage of catalyst at mol% (based on the mass fraction of glucose), two phase ratio of 8:2 (water/methylisobutylketone), reaction time of 1.5 h. The conversion rate of glucose was found to be 98.91%, the 5-HMF yield and product selectivity was 45.91% and 46.14% respectively.