The large-scale cultivation of algae of commercial value requires a variety of important energy-related inputs to achieve the proposed yields required for economic viability. One specific energy input of interest is temperature control and the associated costs of this control, both in terms of initial capital investment and costs associated with continued cooling or heating. In this work, the green algae Neochloris oleoabundans and Scenedesmus dimorphus were grown in tightly-controlled turbidostat-based photobioreactors to determine the potential benefits of temperature control for biomass production of these organisms versus allowing these cultures to experience temperature fluctuations similar to what would be found in uncontrolled, outdoor open ponds or closed bioreactors. The results of these studies indicate stark differences between these two strains, with N. oleoabundans yielding improved growth rates under conditions of stringent temperature control at 22 °C, while S. dimorphus yielded slightly higher growth under conditions where temperature was allowed to fluctuate based on modeled natural temperature profiles. Further analysis reveals that the utilization of non-conventional temperature profiles could enhance growth yields further for N. oleoabundans, allowing it to overcome the detrimental effects of the natural temperature fluctuation. These results and a discussion of the potential for turbidostat-based algal culture growth are presented.
Bibliographical noteFunding Information:
This work was supported in part through a career award to B.M.B. (RC-0007-12) from the Initiative for Renewable Energy and the Environment , a program of the Institute on the Environment at the University of Minnesota, supported by the State of Minnesota and Minnesota electricity ratepayers, Minnesota Agricultural Experiment Station MIN-12-070 and MIN-12-081 and the United States Department of Energy DE FG3608GO18161 . We thank the Microbial Engineering program at the University of Minnesota for additional support to C.M.K. We thank Jack O'Brien and Leland Martineau for efforts related to initiation of the construction of the turbidostat reactor and preliminary studies related to temperature constraints with these two strains. We thank Yaniv Brandvain for helpful suggestions related to statistical analysis of the data.
© 2018 Elsevier B.V.
- Neochloris oleoabundans
- Scenedesmus dimorphus