Biochemical Engineering is therefore that area where the study of how cells behave in a reactor is an essential element. For biological processes, we call the reactor a "fermenter" and the process itself is called "fermentation". Fermentors at the laboratory scale are typically 1 to 20 liters in size. These are used to study, develope and intensify a process. Here it is important to understand the role of medium composition, and other growth parameters such as temperature, aeration, pH, mixing, etc. The next step is to move to larger reactors, or to "scale-up" the process. Industrial fermenters can be from 10,000 up to 1,000,000 liters in size. Usually, scale up studies are conducted at a so-called pilot scale. At our department we have pilot scale fermenters of 300 and 1500 liters. As part of the 4th year study, students at the department will grow bacteria in both laboratory reactors of 14 liter and in a pilot reactor of 300 liter. Scaling up a process can present difficulties since the immediate environment which the cells experience will be different in small and large reactors. These differences can be enough to affect how efficiently the cells carry out their reactions, and will in turn affect the economics and commercial viability of any given process. It is usual to apply the tools of process modelling to process optimization, both at the lab scale and under scale-up. The "upstream" or growth phase of the process is however only part of a commercial process. Usually a product must be recovered and purified. To do this we need also to understand how to apply and optimize typical unit operations such as centrifugation, filtration, chromotagraphy etc. These operations are also a part of Biochemical Engineering.

Our projects are typically carried out in interdisciplinary teams. We collaborate closely with molecular biologists who have the ability to genetically modify cells. While they create new variants of cells for a process, it is the biochemical engineers who test the new cells in reactors under defined conditions. Based on the results obtained either new variants are produced or new strategies for modification are followed. Our most important collaborator is SINTEF Materials and Chemistry, Biotechnology team .

Metabolic Engineering is that aspect of modern biotechnology where we genetically modify organisms to change their metabolism. This is an inter-disciplinary area requiring expertise in genetics, microbial physiology, biochemical engineering and mathematical modelling. Modelling of a cell's metabolism is often essential for interpreting the experimental data, but also for making sensible predictions as to how and what part of a cells "metabolic machinery" to modify. When faced with a cell which makes a product, you have the possiblilty of modifing thousands of enzymes, proteins, or cellular structures--but which one should you change, and how? You can say that the goal of Metabolic Engineering is to create a specially tailored cell to meet a specific process goal.