Characteristics Of Heterotrophic Microalgae

In the heterotrophic production, microalgae are grown in the dark and energized by organic carbon substrates in mixing fermenters or bioreactors. With no necessity for light energy, the system can have smaller surface-to-volume ratio of the reactor. The design can be minimal and easier to control its physical conditions due to no exposure to the outside light source. However, this system requires more total operational energy than the photoautotrophic mechanisms, since this process requires the generation of organic carbon supplies such as glucose through photosynthesis (Chisti 2007). Brennan (2010) has shown higher productivity and generated volume of heterotrophic microalgae than the photoautotrophic methods. Miao and Wu (2006) examined the strain of C. protothecoides and reported their lipid content as high as 55% compared to the autotrophic organisms at only 15% with analogous conditions. …show more content…
Some ideal characteristics of microalgae include: high photosynthetic efficiency value, high lipid content, ability to survive stresses from photobioreactors, capable of withstanding varying temperatures and seasonal conditions, short cell cycle and fast production (Hannon et al 2010). No specific microalgal strain currently meets all of these standards, but the search continues. Different conditions where the microalgae derive from can contribute distinguished advantages. For instance, the Scenedesmus obliquus and Chlorella kessleri extracted from drainage treatment ponds by the power factory show higher CO2 absorption (Morais 2007). In a comparison study, multiple microalgal strains were grown under high CO2 supply, and found that different cultures can have specific functions. B. braunii was considered to be the most sufficient for making biodiesel, while Scenedesmus was found to consume the most CO2 gas from the atmosphere (Yoo et al