FURTHER NOTES ON THE GROWTH AND CHLOROPHYLL FORMATION OF CHLORELLA PROTOTHECOIDES

1. Using area of a fixed concentration as a nitrogen source,cells of Chlorella protothecoides were grown in the presenceof various carbon compounds. Magnitudes of growth of the cellswere widely different depending on the carbon sources used;glucose and fructose being most favourable substrates and galactose,glycerol and acetate coming next. But the amounts of chlorophyllformed in the cells during the experimental period were almost,the same irrespective of the different carbon sources, withsome exceptions. The similarity of the chlorophyll level observedin these experiments seemed to indicate that the formation ofchlorophyll was limited largely by the nitrogen source but notby the carbon source. 2. Strong bleaching effect was recognized with glucose and fructoseat their high concentration, which produced totally chlorophyll-lesscells. On the other hand, a stimulating effect on chlorophyllformation was observed with galactose at the different concentrationsexamined. 3. Effects of glycine and ammonium carbonate as the nitrogensource on the algal growth and pigmentation were studied insome details. The results were similar to those previously obtainedwith urea, confirming our previous conclusion that the algalpigmentation is profoundly affected by the concentration balancebetween glucose and nitrogen source. ¹Present address: Tokyo Research Laboratories, Tanabe SeiyakuCo., Toda-machi, Saitama.