Development of analytical methods to facilitate algal biodiesel production

Irmtraud Horst1, Jennifer C. Mortimer2, Paul Dupree2 and Alison G. Smith1

1) Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EA, UK 2) Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QW, UK

Much current research is focussed on algal-based biodiesel due to the need to replace fossil fuels in the long term. However, in order to make biodiesel production from microalgae a commercial reality, several technical and economical hurdles have to be overcome. So far, researchers are optimising algal biomass production and the triacylglycerol (TAG) content of several algal species either by varying their growth conditions or by genetically engineering their metabolic pathways. However, if the cells do not secrete the TAGs into the surrounding medium, algal cell walls are the final barrier that has to be overcome for extracting TAGs. Solvent extraction is commonly used for recovering TAGs from algal cells which adds considerably to the costs and environmental burden of biofuel production and thus it is desirable to avoid it. Furthermore, contamination problems of TAGs with DNA and chlorophyll have to be removed before the final algal biodiesel can be used. The goal of our research is to investigate alternative options for recovering biofuel molecules from algae. We are working on the improvement of growth conditions to make algae accumulate TAGs. In order to decide on an extraction method, we are determining the precise localisation of the lipid bodies in the cell. Furthermore, we are using methods such as High Performance Anion Exchange Chromatography (HPAEC) and Polysaccharide Analysis using Carbohydrate gel Electrophoresis (PACE) to analyse the cell wall composition of green algae. Our research should ultimately enable us to biologically degrade the cell walls by using enzymes thus minimising the use of solvents in the extraction of TAGs from algal cells.

e-mail address of presenting author: ih269@cam.ac.uk