Some algae have the capability to obtain nutrition by both autotrophic and hetero­trophic methods. This means light energy is not a primary need for mixotrophs as cell growth can occur by digesting organic material. These cultures are shown to lessen photo inhibition with enhanced growth rates as compared to autotrophic and heterotrophic cultures. This is because cultivation of mixotrophs utilizes both pho­tosynthetic and heterotrophic elements, which decreases loss of biomass and reduces the quantity of organic substrate consumed.

13.2.2.3 Photoheterotrophic Cultivation

This mode of cultivation refers to the process in which alga requires light energy and obtains carbon from an organic source. Unlike mixotrophs, photoorganotrophs cannot grow without light energy. Although this process can enhance the production of certain useful light-regulated metabolites, this mode of cultivation is not pre­ferred in case of procedures like biodiesel production.