ISOLATION, PURIFICATION, NUTRITION 39 



of Coccochloris Peniocystis. The amount of growth in two of the 

 four cultures of each treatment was determined after approximate- 

 ly seven days of growth and in the remainder after fourteen days. 

 As in the nitrate experiment, however, a single harvest at fourteen 

 days would have been sufficient, for, although cultures containing 

 suboptimal concentrations of an element usually produced maxi- 



Table 5 — Summary of experiments on the mineral nutrient requirements 

 of Coccochloris Peniocystis. 



The nitrate concentration for all experiments, except that in which 

 nitrate was varied, was 3 X that in the basic solution. 



mum growth within seven days, they did not decrease significant- 

 ly in weight during the second week. For ease of comparison, the 

 yield from each treatment is reported as a percentage of that in the 

 basic solution. Treatment C, rather than as weight of dried cells. 



The concentration of phosphate required for maximum 

 growth was surprisingly low when compared to nitrate. The 

 basic solution. Treatment C, contained only 1.8 ppm. phosphorus, 

 yet maximum growth was still produced at one-fourth this con- 

 centration or at 0.45 ppm. The minimum nitrogen concentration 

 for maximum growth was 13.6 ppm. nitrogen, thus, these results 



