One of the major issues in algal cultures is that productivity and oil yield depends on diverse environment conditions such as different macro and micro nutrient levels as well as light and temperature conditions
It is impossible to answer your question without some information on the algal system you are using. However temperature, sunlight, soluble nitrogen and carbon dioxide concentration are the main variables. There is so much literature on this question ... perhaps search using your specific system.
We are using freshwater green algae! You are right, there is a lot of literature! But I wish to hear from experts in the field, of details which are usually not mentioned in the literature!