Influence of culture conditions on mycelial structure and polygalacturonase synthesis of Aspergillus niger

Biosynthesis of polygalacturonase (PG) by A. niger strain R 1/214 correlates with the morphology of mycelium in submerged culture. The mean specific PG-synthesis (PG-U.g-1.h-1) increases with the degree of compactness of mycelium. PG-production can be optimized by a precise adjustment of the culture conditions after direct spore inoculation (diffuse mycelium) but the high synthesis as by compact mycelium is never obtained. Different reasons for the higher enzyme production by the pellet mycelium are discussed. PG-synthesis is assumed to be strictly connected with a limitation of nutrient and oxygen supply.