The Application of Enzyme and Yeast

Abstract

This bachelor’s thesis concerns the application of enzymes and yeasts for bio-industry. The purpose of this work is to understand the basic knowledge about enzyme and yeast, and meanwhile, to find out their different applications. Through comprehensive study, the knowledge was accumulated which brought a clear understanding for the enzyme structure and yeast microorganism, together with their working principles for the bioprocess.

For wood-based industry, the different enzymes used in bio-pulping process were studied. The lignin-oxidizing enzymes, e.g. laccase, lignin peroxidase and manganese peroxidase, are effectively applied in the biodegradation of lignin. On the other hand, the biodegradation of hemicelluloses needs the present of xylanase and mannanase. Furthermore, the production process for enzymes is introduced which contains raw materials preparation, filtration, concentration, purification, drying, etc.

Concerning the application of yeast, saccharomyces cerevisiae is commonly used in the bio-ethanol fermentation industry. In addition, the operating condition should be carefully selected in the fermentation process in order to improve the productivity. For the waste water treatment industry, the choice of yeast could bring the certain benefit comparing with the traditional process. The various yeasts, e.g. yarrowia lipolytica, candida utilis and candida parapsilosis are commonly applied concerning the waste water from the various industry processes.