Biocatalysis is the study of biological and chemical processes involving biocatalysts, enzymes and proteins. This area of study prepares students for traditional ''upstream'' operations: principles of design and operation of bioreactors and fermenters. Chemical and biological processes often involve reactions at the interfaces of liquid and solid, and are frequently diffusion limited. Understanding of surface activities as well as effective modeling of the process kinetics enables the engineer to design processes with optimal yield, rate of reaction using appropriately sized equipment. These form the core of most bioprocesses in the industry. Pilot plant facilities in these areas are also available.