Placing microalgae on the biofuels priority list: a review of the technological challenges

By H. Chris Greenwell, L. Laurens, R. J. Shields, R. Lovitt, Kevin J. Flynn. Journal of the Royal Society Interface, 2010

867 citations recorded by the source corpus.

Microalgae provide various potential advantages for biofuel production when compared with ‘traditional’ crops. Specifically, large-scale microalgal culture need not compete for arable land, while in theory their productivity is greater. In consequence, there has been resurgence in interest and a proliferation of algae fuel projects. However, while on a theoretical basis, microalgae may produce between 10- and 100-fold more oil per acre, such capacities have not been validated on a commercial scale. We critically review current designs of algal culture facilities, including photobioreactors and open ponds, with regards to photosynthetic productivity and associated biomass and oil production and include an analysis of alternative approaches using models, balancing space needs, productivity and biomass concentrations, together with nutrient requirements. In the light of the current interest in synthetic genomics and genetic modifications, we also evaluate the options for potential metabolic engineering of the lipid biosynthesis pathways of microalgae. We conclude that although significant literature exists on microalgal growth and biochemistry, significantly more work needs to be undertaken to understand and potentially manipulate algal lipid metabolism. Furthermore, with regards to chemical upgrading of algal lipids and biomass, we describe alternative fuel synthesis routes, and discuss and evaluate the application of catalysts traditionally used for plant oils. Simulations that incorporate financial elements, along with fluid dynamics and algae growth models, are likely to be increasingly useful for predicting reactor design efficiency and life cycle analysis to determine the viability of the various options for large-scale culture. The greatest potential for cost reduction and increased yields most probably lies within closed or hybrid closed–open production systems.

Subfields: Biomedical Engineering, Molecular Biology, Renewable Energy, Sustainability and the Environment

View Paper: https://www.semanticscholar.org/paper/d073378ef96bc37dad0f8358121b37e0de51c650

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Citations in the corpus

Biofuels from algae: challenges and potential (2010, background): “In addition, a number of engineering strategies have been examined to increase both light and nutrient utilization, which is discussed elsewhere [110].”
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Sustainable Intensification of Aquaculture through Nutrient Recycling and Circular Economies: More Fish, Less Waste, Blue Growth (2021, methodology): “The sustainable production of microalgal biofuel at large industrial scale is, however, still challenged by finding more economically viable methods of harvesting and lipid extraction (Greenwell et al. 2010; Mata et al. 2013).”
Overview of the potential of microalgae for CO2 sequestration (2014, background): “Microalgae which are primitive, unicellular, microscopic (2–200 lm) organisms that can also be classified as thallophytes have an important ecological role (Khan et al. 2009; Brennan and Owende 2010; Greenwell et al. 2010; Mutanda et al. 2011).”
Microalgae biofuels: A critical review of issues, problems and the way forward. (2012, background): “In this regard, genetic engineering will have an important role in enhancing the overall life cycle of microalgae that are used as biofuels feedstock (Gong and Jiang, 2011; Greenwell et al., 2010; Huang et al., 2010; Radakovits et al., 2010; Rosenberg et al., 2008; Tabatabaei et al., 2011).”
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Long-Term Cultivation of Algae in Open-Raceway Ponds: Lessons from the Field (2015, neutral): “33,34 Rotifers, ciliates, and amoeba were commonly found grazers at the Columbus farm.”
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Effects of flocculants on lipid extraction and fatty acid composition of the microalgae Nannochloropsis oculata and Thalassiosira weissflogii (2011, background): “[34] Greenwell HC, Laurens LM, Shields RJ, Lovitt RW, Flynn KJ.”
Astaxanthin-Producing Green Microalga Haematococcus pluvialis: From Single Cell to High Value Commercial Products (2016, methodology): “This method is most effective when biomass concentration in the algal cake after harvesting is between 100 and 200 g/l (Greenwell et al., 2010).”
Commercial astaxanthin production derived by green alga Haematococcus pluvialis: A microalgae process model and a techno-economic assessment all through production line (2016, methodology): “This method is most effective and energy wise, when biomass concentration after harvesting in the algal cake is between 100 and 200 g/l [35].”
Characterization of Micro Algal Biomass Through FTIR/TGA /CHN Analysis: Application to Scenedesmus sp. (2015, background): “The economics of large-scale cultivation of microalgae strongly depends on the biochemical composition of the algal biomass (Greenwell et al., 2010; Hu et al., 2008; Pienkos and Darzins, 2009).”