Some aspects are described of tlie kinetics of the groivth of (;ibbeie!la fzljik~~ro?:in nitrogen-limited media contai~ling either am~uonium nitrate, ammonium acetate, ammonium tartl-ate, urea, or glycine. Also varied were inoculum size, agitation rate, pI-I, and initial concentrations of glucosc and nitrogen source. The sigiiihcance of kinetic parameters ~lsed in this, and published studies, is discussed.A lag phase n:as only found on ammonium acetate media or when higli concentrations of glucose \\,ere present. Early gro\vth was exponei~tial on all nitrogen sources. On ammonium acetate the specilic growth rate decreased a t a dry weight ofca. 1 mg/g WS (Whole ~~nliltered Samplc). On arnmol~iuin nitrate, early expoiientiaI growth ~~t i l i z e d more NI-13-nitrogen than NOJ-l~itrogen \vith a corlcornitant decrease in pH. I n the range pH 3.0-2.8 NHa-nitrogen uptalre and dry weight increase ceased, but SOs-nitrogen uptalce continued, and the pH increased until growth and NI-I:,-nitrogen uptalce restarted. 'This pattern could be repeated. Finally, expo~lential growth was resumed a t a lo\\, specilic gro\\.th rate. On gIycine, urea, and ammoni~lm tartrate media, exponel~tial growth continned to a dry weight of about 7 mg/g \VS. During, this pcriod the uptalces relative to dry weight (contributions) of glucose, nttrogen, phosphate, and magnesium remained coilstant and were unaffected by the rate of agltatloll, as also was the specihc growth rate, but the latter decreased with increasing glucose concentration.A period of linear growth could folio\\, the exponential period. The contribution bf glucose was ireater, and that of phosphate and magnesium less, than during exponential growth. The dry weight a t which espol~ential growth changed to linear growth \\.as greater the higher the rate of agitation, and this change may be a response to oxygen restriction. After nitrogen exhaustion, fat and carbohydrate accum~llntion in tlie cells largely accour~ted for the increase in dry weight. The specilic rates of dry weight increase and glucose uptake remained constant over the lower range of initial nitrogen concentrations. Both rates decreased with increasing nitrogen over the higher range.Gibberellic acid production began a t , or soon after, nitrogen exhaustion. The amount present increased lirlearly with time. The productivity decreased with increasing glucose conce~~tration; and first increased and then decreased with increasing initial nitrogen. 'I'he maximum amount produced was proportional to the initial nitrogen provided. Some published results are discussed in the light of these relations.

No abstract

The metabolism of Gibberclla Jujikuroi in stirred culture has been studied at varied temperatures over the range 8–40 °C. Two nitrogen-limited media were used, which differed only in the initial concentration of ammonium tartrate. Economic and rate constants have been derived at each stage of fermentation, and methods of relating these to temperature discussed. Each has been related to temperature both by a linear plot, and according to the Van"t Hoff – Arrhenius model.There was no significant difference between the results from the two media early in fermentation. During the storage and maintenance phases all specific rates were considerably lower on the more concentrated medium.The minimum temperature for growth was below 8 °C. Many parameters showed a discontinuity in the range 17–20 °C, and most optima were in the range 29–32 °C. At 38 °C growth ceased when the dry weight was about 2 mg/g of unfiltered broth, and no growth occurred at 40 °C.The contribution of nitrogen to dry weight was virtually independent of temperature. The glucose contribution tended to decrease slightly with increasing temperature over the whole range. The phosphate contribution was constant in the range 8–20 °C, and decreased greatly with increasing temperature from 20 to 36 °C. The magnesium contribution decreased markedly with increasing temperature over the whole range.Two general forms of relation between rate constants and temperature were found. One, a typical "skew" curve with "tail-off' at the lower temperatures, was obtained with the specific growth rate, the nitrogen and glucose quotients, the specific rate of glucose uptake in the maintenance phase, and the gibberellic acid productivity. The second relation showed a marked discontinuity in the range 17–20 °C, above which the increase with increasing temperature was less than at the lower temperatures. This form of curve was obtained with the phosphate, magnesium, and carbohydrate quotients, the linear growth rate, the rate of increase in mycelial dry weight, fat and carbohydrate in the storage phase, and the rate of glucose, phosphate, and magnesium uptake in the same period.