Bioengineering and physiological engineering are two multidisciplinary fields in which microbiology, biochemistry and chemical engineering meet and together generate new knowledge. The understanding of the link between fundamental cell physiology and aspects from the more applied engineering world, such as reactor design and configuration, mass and heat transfer and chemical reaction kinetics, is of great importance to the successful scale-up of biological processes. Theoretical modelling and experimental evaluation of all these phenomena are essential elements in developing a more complete understanding of biological production systems. Xylose is a pentose sugar originating mainly from hardwoods, which traditional baker's yeast cannot utilise. From that point, the research turned towards the fermentation of hexoses for the biotechnical production of ethanol, both for use as a fuel and for alcoholic beverages, based on renewable resources such as wood residues and wheat.
Hexoses are the largest component in the cellulose part of softwoods, such as pine and spruce.
The interest in ethanol production for use as a fuel has increased with the discussion of an enhanced greenhouse effect caused by CO 2 generation originating from the burning of fossil fuels. Biotechnical ethanol production from wood residues is considered to be a CO 2 -neutral process, which means that the net production of CO 2 in the whole process is zero. Research at the Department of Chemical Reaction Engineering has concentrated on ways of increasing the rate and yield of hexose fermentation, avoiding different by-products such as glycerol and acetic acid, and also avoiding stuck fermentation. Traditionally, ethanol production is an anaerobic process although small amounts of oxygen added to the medium can have a positive effect on the ethanol yield. The yield of the product is of course very important in a bulk process such as this.