Lab-scale photobioreactor systems: principles, applications, and scalability

Abstract

Phototrophic microorganisms that convert carbon dioxide are being explored for their capacity to solve different environmental issues and produce bioactive compounds for human therapeutics and as food additives. Full-scale phototrophic cultivation of microalgae and cyanobacteria can be done in open ponds or closed photobioreactor systems, which have a broad range of volumes. This review focuses on laboratory-scale photobioreactors and their different designs. Illuminated microtiter plates and microfluidic devices offer an option for automated high-throughput studies with microalgae. Illuminated shake flasks are used for simple uncontrolled batch studies. The application of illuminated bubble column reactors strongly emphasizes homogenous gas distribution, while illuminated flat plate bioreactors offer high and uniform light input. Illuminated stirred-tank bioreactors facilitate the application of very well-defined reaction conditions. Closed tubular photobioreactors as well as open photobioreactors like small-scale raceway ponds and thin-layer cascades are applied as scale-down models of the respective large-scale bioreactors. A few other less common designs such as illuminated plastic bags or aquarium tanks are also used mainly because of their relatively low cost, but up-scaling of these designs is challenging with additional light-driven issues. Finally, this review covers recommendations on the criteria for photobioreactor selection and operation while up-scaling of phototrophic bioprocesses with microalgae or cyanobacteria.

Recent advances in photobioreactor systems for sustainable and enhanced microalgal biofuel production

“…4a). 87 Bubble column photobioreactors ensure uniform gas supply regardless of location and usually have a cylindrical structure to allow fluid circulation. However, the systems induce shear stress on microalgae cells, which inhibits cell function and causes cell death.…”

Optimization of CO2 Supply for the Intensive Cultivation of Chlorella sorokiniana IPPAS C-1 in the Laboratory and Pilot-Scale Flat-Panel Photobioreactors

“…Intensive cultivation of microalgae is a promising method to capture and utilize the excess carbon dioxide [ 1 , 2 ]. As a result, the task of carbon footprint reduction with the simultaneous production of high-value products, theoretically, has been solved [ 3 , 4 , 5 ] and reflected in a solid number of publications [ 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 ]. It was demonstrated that, depending on a variety of parameters and cultivation conditions, a high carbon fixation rate (CFR) can be achieved [ 6 , 7 ].…”

“…A comparison of fixed amount of CO 2 biomass and M CO2 allows for the estimatation of the efficiency of the gas-air mixture (GAM) supply and CO 2 loss. An increase in the cultivation volume to obtain a higher biomass yield leads to an increase in the CFR value, while the efficiency of CO 2 utilization decreases due to a number of challenges associated with scaling-up, ranging from energy consumption to the design of photobioreactors (PBRs) [ 7 , 10 , 11 ].…”

“…The conditions of GAM supply include parameters such as the concentration of CO 2 in a GAM; R GAM ; GAM supply method; the diameter and trajectory of the bubbles; the geometry of the gas sprayer and the number of holes in it; the presence of baffles in a PBR, etc. [ 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 ]. All these parameters are important for determining the characteristics of the PBRs of various designs.…”

“…The design of such PBRs and the applied technical solutions ensure high efficiency when using the light energy from artificial sources and high efficiency of CO 2 utilization, excluding the contamination of the suspension and providing the possibility of stabilizing the cultivation parameters over a wide range. [ 10 , 11 , 21 , 22 ].…”