Abstract
SUMMARY: Of a large number of possible carbon sources only glucose, galactose, and acetate supported continued growth of Chlorella pyrenoidosa in darkness. Cell synthesis in darkness with nitrate as the nitrogen source proceeded with a carbon assimilation of 45% for glucose, 37% for galactose, and 26% for acetate. The energy efficiency (Rubner coefficient) of cell synthesis from glucose was affected by the nitrogen source and has a maximum value of 58% with ammonia.