Immobilization Of Saccharomyces Cerevisiae Cells Using ZnO Nanoparticles

In recent years,the whole-cell catalysis technology is widely to be applied to various fields. Immobilization of cells is commonly accomplished by physical entrapment within a porous matrix, attachment or adsorption to a pre-formed carrier, or self-aggregation by flocculation and or cell contained behind barrier. However, these methods have some disadvantagers such as low immobilization yield, complex process and low cells’catalytic activity. In polar solution, ZnO nanoparticles can mutual adsorb and then precipitate. Response to this phenomenon, ZnO nanoparticle was attempted used as a kind of new immobilizing material to immobilize Saccharomyces cerevisiae cells.The work could be divided into four sections:The first part:The method of the immobilization of Saccharomyces cerevisiae cells using ZnO nanoparticles is determined. According to this method,1g15nm ZnO nanoparticle can immobilize almost18g Saccharomyces cerevisiae cells(wet weight). This method is easy to operate, strong binding, and does not result in the rupture or deformation of yeast cells.The second part:The optimal conditions of immobilization is determined. After2h40KHZ ultrasonic treatment ZnO nanoparticles get the maximum immobilization ability,and the cells could be100%immobilized longger than20h at100rpm shaking condition. Compared to free cells,the centrifugal speed ZnO-cell composites required decreased by63.4%,and the centrifugal time decreased by83.3%.But the immobilization can not occur when with the substance containing non-polar group.The third part:By measuring the activity of the Saccharomyces cerevisiae cells catalyzes AMP to ATP before and after immobilization, determined the impact of immobilization on cell’s activity.After the immobilization, the activity of the cellls decreased by5%-10%,the optimal conditions of immobilize cell and free cell are the same..The fourth part:After using ZnO nanoparticle as immobilization carrier, the reaction solution and the supernatant of catalytic systems obtained antibacterial capacity. Add at least1*10-2g/ml15nm ZnO nanoparticles can make the reaction solution and the separated supernatant be not contaminated by bacterial.