Research suggests that microalgal-based biofuels offer a promising alternative to fossil fuels, providing significant environmental benefits such as reduced greenhouse gas emissions and a smaller carbon footprint. These biofuels also boast rapid production rates that could match or surpass the modern energy consumption levels currently met by fossil fuels. This makes them an attractive option for sustainable energy solutions.
However, the process of large-scale algae cultivation, which is a critical component in the production of algae-based biofuels, faces challenges due to its susceptibility to opportunistic algal crop predators. These predators, such as rotifers, are small aquatic organisms that can quickly proliferate and devastate large algae populations, leading to substantial losses in biofuel production. This vulnerability highlights the need for effective management and monitoring strategies to ensure the viability and efficiency of algae-based biofuel production systems.
Thus, there is a need to develop a method of early detection and quantification of these potential predatory grazers in algal cultures.
A study from Arizona State University (Wang et al., 2017) tested the capability of the FlowCam to quantify and image low-density populations of predatory zooplankton in high-density algae populations. Read the abstract here.
In this study, Wang et al. tested the ability of the FlowCam to detect and quantify the freshwater rotifer Brachionus calyciflorus at densities ranging from 0.1 individual/mL to 100 individuals/mL within algae densities ranging from 105 algae cells/mL to 107 algae cells/mL. According to the results, the FlowCam could detect and enumerate rotifer concentrations as low as 1 individual/mL at all algal densities tested. Additionally, the FlowCam was able to complete the detection and quantification of ultra-low rotifer densities (0.1 individual/mL) in sample volumes ranging from 10-20 mL within 10 minutes.
Additionally, a study from the University of Georgia, Athens (Abou-shanab et al., 2016) used the FlowCam to investigate the impact of the predatory rotifer Brachionus rubens on the growth of eleven microalgal species, which are potential biofuel sources. The study highlights the susceptibility of different algae to rotifer predation, with Chlorella sorokiniana being the most vulnerable and Synechococcus elongatus and Scenedesmus dimorphus showing resistance by suppressing rotifer growth. The variations in susceptibility are attributed to differences in morphology, cell wall structure, and biochemical composition of the algae. The study emphasizes the need for sustainable solutions to control rotifer contamination in large-scale algal cultivation. quantify the effect of the predatory rotifer attack by Brachionus rubens on eleven different microalgae species over twenty-one days.
FlowCam, a digital flow cytometer, plays a crucial role in this research by enabling precise measurement of algal cell density, size, and shape. It helps quantify the effects of rotifer presence on algal growth characteristics and biomass productivity. FlowCam's imaging capabilities allow for detailed phenotypic characterization of both algae and rotifers, facilitating the analysis of predator-prey interactions. This technology is essential for understanding the dynamics of algal cultures and developing strategies to enhance biomass production while mitigating the impact of rotifer predation.
Interested in learning more? Read how FlowCam can be used for early detection of sparse, predatory populations in algae cultivation.
Read our case study on how Cyanotech uses FlowCam to protect its microalgae cultures.
Citations:
Wang, Y., Castillo-Keller, M., Eustance, E., and Sommerfled, M., (2017), Early detection and quantification of zooplankton grazers in algal cultures by FlowCAM. Algal Research, 21, 98-102.
Abou-shanab, R., Singh, M., Rivera-Cruz, A., Das, K., (2016), Effect of Brachionus rubens on the growth characteristics of various species of microalgae. Electronic Journal of Biotechnology, 22.
