INFLUENCE OF REACTOR SYSTEMS ON THE MORPHOLOGY OF ASPERGILLUS-AWAMORI- APPLICATION OF NEURAL-NETWORK AND CLUSTER-ANALYSIS FOR CHARACTERIZATION OF FUNGAL MORPHOLOGY

The development of germinating spores and the morphology of Aspergillu s awamori were investigated in shake flasks, stirred tank and airlift tower loop reactors under various cultivation conditions. The particul ar morphological features, evaluated by digital image processing, were classifed using an artifical neural network. The input layer consiste d of the morphological features and the cultivation time and the outpu t layer consisted of four object types: globular pellets, elongated pe llets, clumps and filamentous mycelia. The significance of the particu lar morphological features and their combination was determined by clu ster analysis. The effect of temperature, phosphate concentration, rot ation speed and number of baffles on the fungal morphology in shake fl asks, the effect of phosphate concentration and impeller speed in a st irred tank and the effect of phosphate concentration in airlift tower loop reactors were investigated and compared. The relationship of the fungal morphology to process performance was discussed. (C) 1998 Publi shed by Elsevier Science Ltd. All rights reserved.