Study On Preparation Technology Of Xylitol Derived From Brewer's Spent Grain By Biotransformation

The program mainly focuses on four aspects of researches, and the main achievemens of the program is illustrated below.(1) To explore and analyze the feasibility of preparation for xylose and xylitol from brewer's spent grain.(2) Exploring five extraction and preparation technology of obtaining xylose from brewer's spent grain. The research applies the response surface, central composite machine, the general rotation and other design methods to optimize the best condition of technology, based on the qualitative and quantitative analysis of liquid chromatography to obtain the most appropriate preparation technology of xylose.(3) Analyzing decoloration technology of xylose hydrolyzate. The research disscusses the different condition of activated carbon decoloring the hydrolyzatewhich was enzymolyzed based on the optimum condition, finally determined the most appopritate acticated carbon types and the best process parameters.(4) Analyzing the preparation technology of xylitol. Enzymic hydrolysates ofxylose after decoloring was fermentated by Candida tropicalis, the research focused on the four aspects of preparation.Based on the above analysis, the main conclutions are as follows:(1) The traditional preparation technology of xylose was influenced by some factors, such as the raw materials limitation, regional limitation and seasonal limitation. The brewer's spent grain can be a new raw marerials to product xylose, effectly slove the problem of environmental degradationwas aroud the beer manufacturers. Therefore, the technology dissussed in this research provided high value-added for brewer's spent grain and provided a friedly-environmental research ideas.(2) Comparation of six extraction and preparation technology of obtaining xylosefrom brewer's spent grain, obtained the best enzymolysis parameters of the brewer's spent grain. Orthogonal rotating composite test design is applied to the research, constructing engineering regression model of the enzymolysis technology of preparing xylose from brewer's spent grain:Y=10.89405-0.71998X1+0.68158X2+0.83528X3+0.40893X12-0.57489X22+1.1 0727X32-0.55068X1X2+0.03475X1X3+0.63046X2X3X1:fineness of the particles/mesh, X2:liquid-solid ration/ml:g, X3:pH value, the optimimum parameters are:fineness of the particles:80 mesh, liquid-solid:20:1, pH value:5.3, enzymolysis time:80min, enzyme quantity:0.6%, enzymolysis time: 50℃, and the yield rate of xylose reached to 17.49%, Xylose content is up to 11.45% with HPLC analysis and detection. This conclution implied that it is feasible to hydrolyze brewer's spent grain producting xylose following the xylose purity is higher than other methods; higher xylose purity facilitated decoloring treatment of hydrolysate.(3) Different actived carbon decolorization is compared in the research, adsorption characteristics and decolorzation are also discussed. Based on the single-factor analysis, response surface design is applied to detemied the most appropriate decoloring condition and parameters of actived carbon. Constructing the optimum engineering regression model of decoloring technology: Y=-174.13+8.14Z₁+51.815Z₂+5.747Z₃-2.733Z₄+8.37Z₁Z₂-0.524Z₁Z₃-0.057Z₁ Z₄-0.125Z₂Z₃+0.367Z₂Z₄+0.05Z₃Z₄-7.108Z₁2-6.18Z₂2-0.051Z₃2-0.034Z₄2 Z₁: Activated carbon amount/%, Z₂:pH value, Z₃:decoloring tempreture/℃, Z₄:decoloring time/mim. Through the analysis of the equation and related fitting matrix solution process, the optimum parameters of regression equation are: activated carbon amount:1.22%, pH value:5.0, decoloring tempreture:59.2℃, decoloring time:33.75min and the comprehensive evaluation of actived carbon decolorzation of hydrolysate is 98.14%.(4) Comparition of the researches on the fermentation conditions and fermentation nutrient conditions by means of central composite design and response surface methods, the result showed the optimum engineering regression model of the preparation of xylitol from xylose by biotransformation.With response surface design, the optimum engineering regression model of fermentation condition of producting xylitol through fermentating xylosederived from brewer's spent grain by Candida tropicalis is: Y=46.96+2.81X₁+5.05X₂-12.65X₃-0.09X₁X₂+0.02X₁X₃-0.15X₂X₃-0.04X₁2-0. 11X₂2+1.32X₃2Y:xylose conversion/%, X₁:seed age/h, X₂:inoculumconcentration/ml, X₃:Ph value. Through the analysis of the d related equation a fitting matrix solution process, we can found that the optimum parameters are:seed age:26.8h,8.54ml, pH value:5.07, the xylose conversion reached to 74.06%.With the central composite design, the optimum engineering regression model of fermentation nutrient condition of producting xylitol through fermentating xylose derived from brewer's spent grain by Candida tropicalis is:Y=47.79+3.00X₁+1.74X₂+3.57X₃-0.04X₁X₂-0.04X₁X₃+0.02X₂X₃-0.31X₁2-0.1 5X₂2-0.23X₃2Y:xylose conversion, X₁:maltose (g/L), X₂:yeast extract (g/L), X₃:KH2PO4 (g/L). Through the analysis of the equation and related fitting matrix solution process, we can found that the optimum parameters are:maltose:3.97g/L, yeast extract:5.78g/L, KH2PO4:7.67g/L, the xylose conversion reached to 72.46%.On this basis, complex systems optimization technique is used for further optimization of fermentation technology, and then biological fermentation tank is used on the enlargement production. Finally, we get up the 78.43% xylose conversionIn conclution, the results informs us that Candida tropicalis applied to fermentate xylose hydrolysate of brewer's spent grain preparing xylitol is feasible; it has important significance for the technology to guide industrial production of xylitol. Srudy on the preparation of xylose and xylitol from brewer's spent grain which is rich in cellulose and hemicellulose by biotrasformation not only wide ideas, but also product a good economic, social and environmental.