Application Of Microcapsule Technology In The Synthesis Of Biodi Esel

Due to the energy crisis brought by drastic changes of the international situation and environment issues caused by greenhouse gases indiscriminately emission, development of substitute energy resources which are environmental friendly and renewable has become accelerated. As a type of biofuels, biodiesel that has excellent emission and power performance is a very promising one and becoming the research hot spot. Because the traditional homogeneous catalysis process has some inevitable defects, such as multiple side effects, corrosion of equipment and environment pollution by wastewater, heterogeneous catalysis process including solid catalysis and lipase catalysis process gradually become a research focus.In order to solve the problems, this article aimed at biological catalytic conversion of tung oil to produce biodiesel. Owing to their good biocompatibility and economical property, chitosan and sodium alginate were used as microcapsule preparation materials. The calcium-alginate-chitosan microcapsule that immobilized lipase and Trichosporon capitatum were prepared by the mild impulsive electrostatic preparation process. The preparation process of microcapsule with lipase immobilized, the growth and metabolism property of microencapsulated cells and biological catalytic conversion process of biodiesel were investigated successively in this paper. Experimental results obtained were as follow:The influence of preparation conditions on morphology and properties of microcapsules has been studied systemically. The concentration of alginate solution and enzyme content has an important effect on morphology and properties of microcapsules. Chitosan molecular weight and solution concentration controlled microcapsule membrane creation and thus influenced enzyme activity. Chitosan solution pH regulated ionization state of functional groups in chitosan and alginate molecule, electrostatic binding of membrane generation, as well as enzyme protein encapsulation rate step by step, finally impacted enzyme activity. Under the preparation conditions that lipase/alginate ratio 15 mg/mL, alginate solution concentration 10 mg/mL, molecular weight of chitosan 50kDa, chitosan solution concentration 1mg/mL with pH=3.0, maximum enzyme activity was obtained ultimately.Because of the microcapsule membrane, the growth of microencapsulated cells lagged slightly, but gained a more stable growth and a higher enzyme activity.Adding olive oil in medium could induce Trichosporon capitatum producing more lipase, and show the secondary growth phenomenon. Comparing to free culture, microencapsulated cells adjusted to adapt a wider favorable pH range but the same suitable temperature.The process of catalysis tung oil to biodiesle using immobilized lipase also has been established preliminary in this thesis. Water content, alcohol/oil ratio, lipase amount, reaction temperature and organic solvents have the important effects on yield of fatty acid methyl ester. The highest yield was obtained under optimizing reaction conditions as follow, water content of 8wt.%, lipase amount of 8wt.%, alcohol/oil ratio of 3 and alcohol that was fedded three-step with equal amount, temperature of 35℃, petroleum ether as solvent, reaction time of 48 hours.The microcapsule immobilized cells using as the whole-cell catalyst has applied into the transesterification of tung oil, and gained some amount of fatty acid methyl ester. These have demonstrated that the method has certain potential in the field of biodiesel production.