Abstract: Disclosed is a culture system for the production of algae biomass to obtain lipid, protein and carbohydrate. By integrating heterotrophic processes with a phototrophic process in parallel, this system provides year around production in colder climates. By integrating heterotrophic processes with a phototrophic process in series, this system creates a two-stage, separated mixed-trophic algal process that uses organic carbon and nutrients for the production of seed in the heterotrophic process, followed by release of cultured seed in large-scale phototrophic culture for cell biomass accumulation. Organic carbon source including waste materials can be used to feed the heterotrophic process. The production capacity ratio between the heterotrophic and the phototrophic processes can be adjusted according to season and according to the availability of related resources. The systems are used for producing and harvesting an algal biofuel feedstock as well as other potential high-value products.