Balanced mixotrophy method

A method of growing a mixotrophic culture of microorganisms, comprising:

• a. Providing a culture of mixotrophic microorganisms in an aqueous culture medium with a supply of carbon dioxide and a supply of organic carbon comprising at least one organic carbon source selected from the group consisting of acetic acid and acetate;
• b. Circulating the culture of mixotrophic microorganisms through a circulation path of a bioreactor system selected from the group consisting of a tubular bioreactor and a raceway pond, wherein the culture receives the supply of carbon dioxide and the supply of organic carbon in the circulation path;
• c. Detecting a pH level and a dissolved oxygen level in the culture with at least one sensor disposed along the circulation path;
• d. Continuously adjusting the supply of carbon dioxide and organic carbon to the culture based on the detected pH level and dissolved oxygen level in the culture, wherein:
• i. the carbon dioxide is supplied and the organic carbon is not supplied when the detected pH level is above a predetermined threshold level and the detected dissolved oxygen level is below a predetermined threshold level;
• and
• ii. the carbon dioxide is not supplied and the organic carbon is supplied when the detected pH level is above a predetermined threshold level and the detected dissolved oxygen level is above a predetermined threshold level.