Guaiacol Degradation By Laccase In The Reverse Micelle Systems

Lignin is a kind of organic macro molecule extremely rich in nature only inferior to cellulose material. There is a regeneration rate to 500 tons of lignin emerging per year. Pulp and paper industry isolated about 1.4 billion tons of cellulose from the plant each year, and there is about 50 million tons of lignin as by-product; industrial products as dispersing agent, adsorbent/depolymerization, oil recovery additives, asphalt emulsifier also used the lignin and its derivatives. So far, there are more than 95% of lignin is released into the environment as "black liquor" without being disposed effectively or concentrated burned rarely being effectively used.Reverse micelles is a surfactant suspended in non-polar organic solvent and spontaneous formation of clear and stabilized homogeneous W/O Nano size aggregates when the concentrations above the critical micelle concentration (CMC). In reverse micelle, the non-polar hydrophobic groups of surfactant contact with the external non polarity organic solvent, while the surfactant polar groups arranged around a dissolved polar substances polar core. The polar nucleus dissolved water, formed a "pool" (water pool). This structure of reverse micelle provides a location for both hydrophilic enzymes and hydrophobic substrates. This makes it possible to be used as micro reactors for enzymes, which mimic the status of intracellular water, lead a superactivity of enzyme in reverse micelle. Therefore, in recent years, reverse micelle enzyme catalysis system has been widely attentioned and researched.In this paper, we investigated the lipophilicity lignin model compounds and hydrophilic laccase dissolved in the reverse micelle solution, explore the catalytic performance of laccase in a novel reverse micelles. Through experiments, established the effect of several significant factors on the catalytic performance of laccase in reverse micelles, determined the optimum reaction conditions of laccase catalytic efficiency of guaiacol, and established the reaction kinetic model and kinetic parameters, in-depth study of the reaction mechanism of laccase catalyzed guaiacol in reverse micelles. The specific research work and achievements of this paper include the following 3 parts:We constructed the reversed micelles based on the surfactants of CTAB, Tween-80, AOT and rhamnolipid; the efficiency and kinetics mechanism of laccase catalytic degradation of guaiacol were measured under the determined optimum surfactant concentration and corresponding water solubilization Wo of CTAB, Tween-80, AOT and rhamnolipid reverse micelle systems. And the reaction products were determined, with existing research for analyzing the reaction mechanism of enzyme catalytic degradation of guaiacol research in reverse micelles.; adopt glycerin modified reverse micelles system which adopted rhamnolipid as surfactant, the catalytic performance of laccase in guaiacol catalytic properties were studied. Construction rhamnolipid/isooctane/is hexanol/glycerol/water reverse micelles system. According to before and after being glycerol modified, the effect of several significant factors as the concentration of RL, maximum solubilization of water conditions on the catalytic performance of laccase have been investigated and compared respectively.The results show that the activity of laccase activity was related to surfactant concentration and corresponding water solubilization. In CTAB, Tween-80, AOT and rhamnolipid reverse micelle systems, the optimum surfactant concentrations were 20mmol/L,50mmol/L,30mmol/L and 10mmol/L with corresponding water content of 20,25, 10and 30mmol/L, respectively. The surfactant type on the catalytic activity of reverse micelle systems was also studied. The results showed that the transforming rate of substrate in the micelle system constructed by anionic surfactant was higher than these of the others, and the rhamnolipid micelle system performed best. Which indicated that the anionic surfactant is more suitable for the laccase reaction, it was found that both of laccase's catalytic activity and stability in rhamnolipid biosurfactant reverse micelle were higher than those of others. After 6hours, under the substrate guaiacol concentration of lmmol/L, the conversion rate of guaiacol in CTAB, Tween80, AOT and rhamnolipid reverse micelle could reach 21.33%,30.85%, 36.02% and 65.45%, respectively.The reaction in four kinds of reverse micelles followed the Michaelis-Menten kinetics, respectively. By participating in guaiacol depolymerization and polymerization, the guaiacol changed to water soluble substrate 4-methyl phenol.After glycerol modified the reverse micelle, the reverse micelle radius may be increased, which is good for laccase molecules dissolved and enhanced enzyme conformation stability in reverse micelle, to improve the activity and stability of laccase.