Optimization of the Hydrolysis Process of Microcrystalline Cellulose with Concentrated Sulphuric Acid
O. V. YATSENKOVA1, R. Z. PEN2, A. M. SKRIPNIKOV1, N. G. BEREGOVTSOVA1, B. N. KUZNETSOV1,3
1Institute of Chemistry and Chemical Technology, Siberian Branch, Russian Academy of Sciences, Krasnoyarsk, Russia
2Siberian State Technological University, Krasnoyarsk, Russia
3Siberian Federal University, Krasnoyarsk, Russia
Keywords: микрокристаллическая целлюлоза, гидролиз, концентрированная серная кислота, глюкоза, выход, оптимизация, ингибиторы ферментации, microcrystalline cellulose, hydrolysis, concentrated sulphuric acid, glucose, yield, optimization, fermentation inhibitors
Abstract
The effect of conditions (temperature, liquid module, and duration) of monocrystalline cellulose (MCC) hydrolysis with 80 % H2SO4 on the conversion degree of cellulose and on the yield of glucose was studied. The major advantage of the use of concentrated sulphuric acid in cellulose hydrolysis, in comparison with its diluted solutions, consists in achieving high yields of monosugars at low temperature and at atmospheric pressure at reduced power imputs. The optimum operating parameters of the process of MCC hydrolysis, at which the maximum yield of glucose and the minimum content of admixtures that inhibit the enzymatic synthesis of bioethanol are reached, were determined by experimental and calculation methods. Statgraphics Centurion XVI software package, DOE block (Design of Experiment) was used for mathematical data processing. Analysis detected a significant impact of three major factors on the conversion degree of cellulose: Х1, Х2 and Х3 - hydrolysis temperature, duration and liquid module, respectively, and on the yield of glucose - factors X1, Х2 and Х3 . The individual composition and content of monosugars in the hydrolysates obtained was studied by the chromatographic method using a Varian-450 GC gas chromatograph. The determination of the quantitative content of furfural, 5-hydroxymethylfurfyral (5-HMF) and in samples of glucose hydrolysates was carried out by the HPLC method using a Milichrom A-02 microcolumn liquid chromatograph. The yield of glucose in the hydrolysate obtained under conditions close to optimum is 98.7 mass %, and the content enzymatic processes inhibitors (furfural, 5-HMF, and levulinic acid) is significantly lower than the permissible values.
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