This chapter covers how microscopic to macroscopic organisms are cultured in machines, called bioreactors, which are composed of the organisms with media, circulation, and insertion of gases and liquids to foster maximal development and growth. Bioreactors have a variety of designs and are used extensively on Earth for biofuel, pharmaceutical, chemical, beverage, and food production. Two major types are covered: photobioreactors that use light and yeast-bacteria bioreactors that use feedstock or wastes. Various designs, support, and mass flow for each bioreactor design to assemble a stage are key topics.