. The actinomycetes. Actinomycetales. 116 THE ACTINOMYCETES, Vol. I Table 19 Metabolic changes characterizing the two phases during the submerged growth of S. griseus (Dulaney and Perlman) Phase I Phase II Streptomycin pH Mycelium Glucose Soluble carbon Lactic acid Oxygen demand Soluble nitrogen Inorganic phosphorus Slight production Gradual rise Rapid growth Rapid utilization Gradual utilization Slow production and utilization Maximum Used extensively Used at maximum rate Maximum rate of production Reaches maximum Gradual autolysis Small remaining amount exhausted Concentration reaches maximu
. The actinomycetes. Actinomycetales. 116 THE ACTINOMYCETES, Vol. I Table 19 Metabolic changes characterizing the two phases during the submerged growth of S. griseus (Dulaney and Perlman) Phase I Phase II Streptomycin pH Mycelium Glucose Soluble carbon Lactic acid Oxygen demand Soluble nitrogen Inorganic phosphorus Slight production Gradual rise Rapid growth Rapid utilization Gradual utilization Slow production and utilization Maximum Used extensively Used at maximum rate Maximum rate of production Reaches maximum Gradual autolysis Small remaining amount exhausted Concentration reaches maximum and remains constant Slow utilization Decreases to minimum Concentration increases Released into medium the culture increasevS, pointing to the pref- erential utilization of the proteins as a source of energy. With the advance in growth, sugar utilization and ammonia consumption proceed at a rapid rate, parallel to the in- crease in dry weight of the organism. Dulaney and Perlman divided the meta- bolic processes of actinomycetes into two phases, crescense and senescence. In the first phase, there was uptake of soluble nitrogen, carbon, and phosphate into the mycelium; the oxygen demand was high and the utilization of glucose was rapid, but there was very little antibiotic production. In the second phase, mycelial weight de- clined, phosphate and nitrogen were ex- creted into the medium, oxygen demand fell, and streptomycin was produced. Some. 6 8 TIME', DAYS Figure 55. Metabolism of *S. griseus (Repro- produced from: Cochrane, V. W. and Dimmick, I. J. Bacteriol. .58: 727, 1949). lactate also formed during the early stages, but this disappeared rapidly (Table 19). Van Dyck and DeSomer also recognized two stages in the growth of a streptomyces (S. aureofaciens). The first stage is char- acterized by cell synthesis and nutrient up- take. The second stage is characterized by a slower increase in cell synthesis; protein and ribonucleic acid decrease, and desoxja-ibo- nucleic acid
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