Article: Jain, A; Voulis, N; Jung, EE; Doud, DFR; Miller, WB; Angenent, LT; Erickson, D; (2015) “Optimal Intensity and Biomass Density for Biofuel Production in a Thin-Light-Path Photobioreactor”, Environmental Science & Technology, 49 (10):6327-6334
Abstract: Production of competitive microalgal biofuels requires development of high volumetric productivity photobioreactors (PBRs) capable of supporting high-density cultures. Maximal biomass density supported by the current PBRs is limited by nonuniform distribution of light as a result of self-shading effects. We recently developed a thin-light-path stacked photobioreactor with integrated slab waveguides that distributed light uniformly across the volume of the PBR Here, we enhance the performance of the stacked waveguide photobioreactor (SW-PBR) by determining the optimal wavelength and intensity regime of the incident light. This enabled the SW-PBR to support high-density cultures, achieving a carrying capacity of OD730 20. Using a genetically modified algal strain capable of secreting ethylene, we improved ethylene production rates to 937 mu g L-1 h(-1). This represents a 4-fold improvement over a conventional flat-plate PBR. These results demonstrate the advantages of the SW-PBR design and provide the optimal operational parameters to maximize volumetric production.
Funding Acknowledgement: Advanced Research Project Agency, Energy [DE-AR0000312]; National Science Foundation [ECCS-0335765].
Funding Text: This work was supported by the Advanced Research Project Agency, Energy (DE-AR0000312). This work was performed in part at the Cornell Nano Scale Facility, a member of the National Nanotechnology Infrastructure Network, which is supported by the National Science Foundation (Grant ECCS-0335765). We thank Jianping Yu, Ph.D. (NREL, Golden, CO) for providing the Synechocystis sp. FCC 6803 2x EFE algal strain. We thank Rose Harmon for assistance with gas analyses.