Potential of Chlorella Species as Feedstock for Bioenergy Production: A Review

Selection of appropriate microalgae strain for cultivation is essential for overall success of large-scale biomass production under particular environmental and climate conditions. In addition to fast growth rate and biomass productivity, the species ability to grow in wastewater must also be considered to increase the economic feasibility of microalgae for bioenergy purposes. Furthermore, the content of bioactive compounds in a strain must be taken into account to further increase the viability by integration of biorefinery concept. Chlorella spp. are among the most studied microalgal species. The present review attempts to unfold the potential of species of the genus Chlorella for bioenergy production integrating applicability for wastewater treatment and production of high added-value compounds. Several key features potentially make Chlorella spp. highly beneficial for bioenergy production. Fast growth rate, low nutritional requirements, low sensitivity to contamination, adaptation to fluctuating environments, ability to grow in photoautotrophic, heterotrophic and mixotrophic conditions make Chlorella spp. highly useful for outdoor cultivation coupled with wastewater treatment. Chlorella is a source of multiple bioactive compounds. Most promising high-value products are chlorophylls, lutein, β-carotene and lipids. Here we demonstrate that although many Chlorella spp. show similar characteristics, some substantial differences in growth and response to environmental factors exist.