In this project the physiology and growth of Rhizopus arrhizus was investigated in detail with a view to developing an industrial fermentation process to produce a lipase enzyme. Spore and vegetative inocula were examined and biomass production was optimized in flasks and fermenters. Pelleting of growth was controlled by developing suitable inoculum procedures and media. Storage conditions for stock cultures were optimized also as part of this work. Factors affecting lipase production were investigated initially m shake-flasks, and later in stirred laboratory fermenters. The inoculum development and production fermentations were then integrated and scaled-up to plant-scale (3,000 litres). Economic yields of lipase were obtained at this scale. Other experiments were conducted to determine the biochemical characteristics of several lipase enzymes and to develop a rapid and inexpensive lipase assay. Finally, growth morphology of R. arrhizus was examined m a range of media to investigate some possible causes and mechanisms associated with pelleting of growth.