mini:kal MirrAHoi.isM and iifff-ct oi" sai/fs ox ckowtm 



\:\9 



cent of tlio niaxiniuin antibiotic product ion 

 took j>lac(> with oO parts per nnllion of zinc. 

 Tlic addition o\' ().()') part per niillion of cop- 

 jxT it'sultcd in optimum {!;ro\vtli and anti- 

 biotic production. Iron afTcctcd ii;ro\\lh and 

 formation of tlio antibiotic at ditfcM'cnt IcncIs: 

 optinnun concentration for f^rowtii was 0.8 

 l)art per million, wliereas ojitinunn antil)i- 

 otic production required 1.0 to 2.0 parts of 

 copper. Xo etTect of manganese could be ob- 

 served o\er a range of O.OOo to 50 parts jicr 

 million. 



Thornberry and Anderson developed a 

 synthetic medium for streptomycin produc- 

 tion which contained, in addition to carbon 

 and nitrogen sources, potassium, magne- 

 sium, zinc, iron, copper, and manganese. The 

 effect of a number of metals was studied bj^ 

 adding the metals to, or omitting them from, 

 this medium. Growth was estimated by com- 

 l)arison with that obtained in a complex me- 

 dium. The conclusion was reach(>d that po- 



tassium, magnesium, zinc, and iron were 

 needed for good streptomycin production 

 and supported excellent growth. .Manganese 

 sliinulalcd antibiotic production but liad no 

 citect on growth. Calcium had no effect on 

 either antibiotic production or growth. 



Temple found that magnesium and potas- 

 sium exerted the most noticeable effect on 

 both growth and antibiotic production. Iron 

 had a lesser effect on growth but was re- 

 ((uii-ed for high streptomycin yields. A modi- 

 fication of Thornberry's medium to contain 

 annnonium citrate and inositol required ad- 

 ditional calcium. If tap water were used in 

 place of distilletl water, no additional cal- 

 cium was needed. Saunders and Sylvester re- 

 ported that traces of zinc, copper, iron, mag- 

 nesium, and manganese were necessary for 

 optimum streptomycin production. Principe 

 and Thornberry found that the addition of 

 cobalt in a concentration of 0.003 M in- 

 creased streptomycin production by 83 per 



PARTS PEI>. MILLION OF METAL ADDED. 



Figure 66. Effect of copper and manganese on surface growth and i)igment production by &. griseus 

 (Reproduced from: Spilsbury, J. F. Brit. Mycol. Soc. Trans. 31: 215, 1948). 



