The influence of maintenance energy and growth rate on the metabolic activity, morphology and conidiation of Penicillium chrysogenum.

SUMMARY: The rates of utilization of energy-yielding substrates (glucose and oxygen) by Penicillium chrysogenum in glucose-limited chemostat cultures were resolved into requirements or ‘rations’ for growth and maintenance. The maintenance ration of glucose was almost all oxidized to carbon dioxide. Over the growth rate range 0.023--0.075 hr-1 only vegetative growth occurred; although the filamentous growth form predominated, the occurrence of pellets and swollen organisms increased with growth rate. At growth rates of 0.014 hr-1 and below, conidiation occurred and was maximal at a specific growth rate of 0.009 hr-1 (average doubling time 78 hr). After growth in chemostat culture the organism could be maintained in a non-growing state by supplying only the maintenance ration of glucose (0.022 g. glucose g. mycelial dry wt/hr). When growth in the chemostat was suddenly stopped by stopping the glucose feed, the mould autolyzed; autolysis was prevented by supplying the maintenance ration of glucose. When the glucose feed rate in chemostat cultures was decreased to the maintenance ration, mycelial differentiation occurred. Differentiation involved increased hyphal vacuolation, a decreased degree of oxidation of glucose, breakdown and resynthesis of nucleic acids and conidiation. The rates at which these changes occurred were inversely related to the growth rate prior to stopping growth. For maximum conidia formation there was an optimal glucose feed rate about 0.038 g. glucose/g. mycelial dry wt/hr, that is 1.7 x maintenance ration. The maintenance ration of glucose was shown to play a role in preventing autolysis and facilitating conidiation. Electron microscope studies showed that there was no change in the observed ultrastructure of cells (except degree of vacuolation) with change in specific growth rate from near the maximum to zero. The septa of the hyphae were found to be plugged.

[1]  O. Maaløe,et al.  Dependency on medium and temperature of cell size and chemical composition during balanced grown of Salmonella typhimurium. , 1958, Journal of general microbiology.

[2]  A. Shatkin,et al.  Electron Microscopy of Neurospora crassa Mycelia , 1959, The Journal of biophysical and biochemical cytology.

[3]  S. Pirt,et al.  Effect of Growth Rate on the Synthesis of Penicillin by Penicillium chrysogenum in Batch and Chemostat Cultures. , 1967, Applied microbiology.

[4]  P. Robinson,et al.  Isolation and Bioassay of a Fungal Morphogen , 1964, Nature.

[5]  A. Morton.  The induction of sporulation in mould fungi , 1961, Proceedings of the Royal Society of London. Series B. Biological Sciences.

[6]  D. Tempest,et al.  Effect of dilution rate and growth-limiting substrate on the metabolic activity of Torula utilis cultures. , 1965, Journal of general microbiology.

[7]  G. Savage,et al.  The Relation of Natural Variation in Penicillium notatum to the Yield of Penicillin in Surface Culture , 1947, Journal of Bacteriology.

[8]  A J Moyer,et al.  Penicillin: VIII. Production of Penicillin in Surface Cultures. , 1946, Journal of bacteriology.

[9]  K. Burton.  A study of the conditions and mechanism of the diphenylamine reaction for the colorimetric estimation of deoxyribonucleic acid. , 1956, The Biochemical journal.

[10]  S. Pirt,et al.  Improved control of organism concentration in continuous culture of filamentous micro-organisms. , 1967, The Journal of applied bacteriology.

[11]  S. Pirt,et al.  Continuous-Flow Culture of the Filamentous Mould Penicillium Chrysogenum and the Control of its Morphology , 1959, Nature.

[12]  F. G. Jarvis,et al.  The role of the constituents of synthetic media for penicillin production. , 1947, Journal of the American Chemical Society.

[13]  J. V. Alexander,et al.  MULTIPERFORATE SEPTATIONS, WORONIN BODIES, AND SEPTAL PLUGS IN FUSARIUM , 1965, The Journal of cell biology.

[14]  S. Pirt.  A theory of the mode of growth of fungi in the form of pellets in submerged culture , 1966, Proceedings of the Royal Society of London. Series B. Biological Sciences.

[15]  C. Harrold,et al.  The Sporulation of Penicillium notatum Westling in Submerged Liquid Culture II. THE INITIAL SPORULATION PHASE , 1958 .

[16]  J. H. Smith.  ON THE EARLY GROWTH RATE OF THE INDIVIDUAL FUNGUS HYPHA , 1924 .

[17]  J. Revel,et al.  IDENTIFICATION OF GLYCOGEN IN ELECTRON MICROGRAPHS OF THIN TISSUE SECTIONS , 1960, The Journal of biophysical and biochemical cytology.

[18]  L. Hawker.  The Influence of Various Sources of Carbon on the Formation of Perithecia by Melanospora destruens Shear in the Presence of Accessory Growth Factors , 1939 .

[19]  S. J. Pirt,et al.  STUDIES OF THE GROWTH OF PENICILLIUM CHRYSOGENUM IN CONTINUOUS FLOW CULTURE WITH REFERENCE TO PENICILLIN PRODUCTION , 1960 .

[20]  L. Hawker,et al.  Sporulation in Rhizopus sexualis and Some Other Fungi Following a Period of Intense Respiration , 1962 .

[21]  S. Pirt.  The maintenance energy of bacteria in growing cultures , 1965, Proceedings of the Royal Society of London. Series B. Biological Sciences.