Study On The Effect And Mechanism Of Surfactant For Biological Catalysis Lignocellulose

Facing the exhaustion of petroleum resources, it becomes a crucial task to develop new energy; facing the rapid expansion of the population and the food shortage in the world, producing fuel ethanol with grain will be restricted. The cellulose resources have advantages such as rich resource, many varieties and short regeneration time. Producing fuel ethanol with agricultural straw is considered as the fundamental way of solving the high cost and the limited of raw materials. This technology is of a good developing future.The lignocellulose is complex in structure. The package of lignin and hemicellulose, the complexity of aggregation structure of cellulose and the high crystallinity of cellulose cause the low accessibility of cellulose to reagent and the low dissolution of cellulose. These affect the contact of enzyme and substrate directly, and then affect the saccharification rate of enzymatic catalysis hydrolysis. Therefore, if people want to make full use of cellulose resources, they must carry on the effective pretreatment first. After pretreatment of lignocellulose, the hemicellulose is dissoloved and separated, the lignin exposes partially, a lot of enzyme adsorbes on the surface of lignin, it is very unfavorable to the process of enzyme hydrolyzing cellulose, so it is very important to decrease the ineffective adsprption of enzyme.The degradation of biological enzyme to lignocellulose is the core of the paper,the ultrasonic assisted alkali pretreatment technique and the surfactant assisted enzyme-catalysis technique were studied in this paper, moreover, the related technology parameters and the influencing factors were discussed.The compound technique of ultrasonic assisted alkali pretreatment was mainly studied in this paper. Through analysis, it can be seen that the lignin in the material could be effectively removed through the ultrasonic assisted alkali pretreatment, and the order lattice degree of crystalline cellulose was decreased; the material treated with ultrasonic assisted alkali was catalyzed by cellulose for 48h, the saccharification rate attained 31.46%.Nonionic surfactant can increase the hydrolysis rate of enzyme catalysis and decrease the adsorption of enzyme on the solid surface, surfactant-polyethylene glycol(PEG2000, PEG4000, PEG20000)was applied in the process of the compound enzyme catalyzing the lignocellulose materials, the effect of the concentration of PEG4000 and different temperatures on the enzyme-catalyzed hydrolysis and adsorption was mainly investigated. The optimum conditions of the enzyme-catalyzed hydrolysis: the hydrolysis temperature was 50℃, the pH value was 5.5, the shaking speed was 120rpm, the reaction time was 48h, the dosage of the compound enzyme preparation was 1.5%, the ratio of solid to water was 1:30, the mass ratio of surfactant (PEG4000) to the enzyme-catalyzed hydrolysis material was 0.025g/g. The enzyme catalysis efficiency could be increased by PEG2000, PEG4000 and PEG20000, the enzyme catalysis efficiency improved by 51.06% with PEG4000 at comparatively high temperature, the adsorption quantity of cellulase was decreased by 11.25%.The mechanism of PEG to enzyme catalysis was also discussed, PEG adsorbed on the surface of lignin through hydrogen bond interaction and hydrophobic interaction, preventing the non-specific binding of enzyme and lignin, thus the non-specific adsorption was decreased.