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Effect of pH and temperature on morphology of batch and chemostat cultures of Penicillium chrysogenum

1983; Cambridge University Press; Volume: 81; Issue: 2 Linguagem: Inglês

10.1016/s0007-1536(83)80069-2

0007-1536

Elizabeth A. Miles, Anthony P. J. Trinci,

Fungal Biology and Applications

Batch cultures of Penicillium chrysogenum were grown on solid and liquid media. The mean hyphal extension rate of mycelia on solid medium was a function of the length of the organism's hyphal growth unit and its specific rate. The optimum temperature for colony expansion was 20°C, although the fastest specific growth rate was observed at 30∘. The reduction in colony radial growth rate at 30° was associated with a decrease in hyphal growth unit length. When P. chrysogenum was grown in glucose-limited chemostat cultures at stirrer speeds of 1000 or 1200 rev./min, hyphal growth unit length decreased with increase in dilution rate. However, at a stirrer speed of 500 rev./min, hyphal growth unit length increased with increase in dilution rate. When the mould was grown at a constant dilution rate but at various temperatures or pH values, maximum hyphal growth unit lengths were observed at 30∘ and pH 6.0. A direct relationship was observed between dilution rate and the nitrogen content of glucose-limited chemostat cultures. Mycelia grown in ammonium-limited chemostat cultures contained only about half the nitrogen content of mycelia grown at the same dilution rate in glucose-limited cultures.