Search NASA⌕ Search

SEARCH · Search NASA

Results for “MICROALGAE”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2026

The Energy Costs of Dewatering Feedstock Microalgae Species Using Conventional Implementations of Ultrasonic and Crossflow Filtration Technologies

The use of microalgae as a feedstock for biofuels and other products continues to be explored, but large-scale biomass production faces persistent high costs. One major cost contributor is the energy required for harvesting and dewatering, a challenge resulting from the dilute nature of microalgae cultures as well as the properties of microalgae cells. This study investigated the energy demands of concentrating three diverse microalgae species (Nannochloropsis salina, Scenedesmus obliquus, and Chlorella luteoviridis) exhibiting different settling velocities, a key harvesting property, using conventional ultrasonic and crossflow membrane filtration. Membrane-free ultrasonic filtration removed 60-80% of the microalgae largely in steady-state operations, increasing concentrations 20-100 times, while consuming 1-6 kWh/m3 - similar to centrifugation. In contrast, crossflow membrane filtration retained nearly 100% of the microalgae, increasing concentrations over 20-fold, but consumed 158 kWh/m3 - over 10 times the energy of centrifugation. Both approaches exceeded the 10% energy target suggested in the 2010 National Algal Biofuel Technology Roadmap. This study also highlights potential sources of energy savings. For ultrasonic filtration, attention to an innovative, dynamic property of the ultrasonic chamber called the Energy Efficiency Factor, could lead to energy reductions by no more than 10-fold and improve the favorability of two of the microalgae species studied. For membrane filtration, a dead-end configuration could reduce energy consumption by no more than 1000-fold, making it favorable for all three species. This study not only highlights the need to further increase the energy content of microalgae cultures, but also the critical importance of continued development of ultrasonic filtration and other harvesting technologies to achieve low-cost, energy-sustainable algal biofuels.

09 BIOMASS FUELS↗
DOE OSTI2011

National Microalgae Biofuel Production Potential and Resource Demand

Microalgae continue to receive global attention as a potential sustainable "energy crop" for biofuel production. An important step to realizing the potential of algae is quantifying the demands commercial-scale algal biofuel production will place on water and land resources. We present a high-resolution national resource and oil production assessment that brings to bear fundamental research questions of where open pond microalgae production can occur, how much land and water resource is required, and how much energy is produced. Our study suggests under current technology microalgae have the potential to generate 220 billion liters/year of oil, equivalent to 48% of current U.S. petroleum imports for transportation fuels. However, this level of production would require 5.5% of the land area in the conterminous U.S., and nearly three times the volume of water currently used for irrigated agriculture, averaging 1,421 L water per L of oil. Optimizing the selection of locations for microalgae production based on water use efficiency can greatly reduce total water demand. For example, focusing on locations along the Gulf Coast, Southeastern Seaboard, and areas adjacent to the Great Lakes, shows a 75% reduction in water demand to 350 L per L of oil produced with a 67% reduction in land use. These optimized locations have the potential to generate an oil volume equivalent to 17% of imports for transportation fuels, equal to the Energy Independence and Security Act year 2022 "advanced biofuels" production target, and utilizing some 25% of the current irrigation consumptive water demand for the U. S. These results suggest that, with proper planning, adequate land and water are available to meet a significant portion of the U.S. renewable fuel goals.

02 PETROLEUM↗
DOE OSTI2012

Recent developments in the production of liquid fuels via catalytic conversion of microalgae: experiments and simulations

Due to continuing high demand, depletion of non-renewable resources and increasing concerns about climate change, the use of fossil fuel-derived transportation fuels faces relentless challenges both from a world markets and an environmental perspective. The production of renewable transportation fuel from microalgae continues to attract much attention because of its potential for fast growth rates, high oil content, ability to grow in unconventional scenarios, and inherent carbon neutrality. Moreover, the use of microalgae would minimize ‘‘food versus fuel’’ concerns associated with several biomass strategies, as microalgae do not compete with food crops in the food chain. This paper reviews the progress of recent research on the production of transportation fuels via homogeneous and heterogeneous catalytic conversions of microalgae. This review also describes the development of tools that may allow for a more fundamental understanding of catalyst selection and conversion processes using computational modelling. The catalytic conversion reaction pathways that have been investigated are fully discussed based on both experimental and theoretical approaches. Finally, this work makes several projections for the potential of various thermocatalytic pathways to produce alternative transportation fuels from algae, and identifies key areas where the authors feel that computational modelling should be directed to elucidate key information to optimize the process.

09 BIOMASS FUELS↗
DOE OSTI2018

Defatted Microalgae-Mediated Enrichment of n–3 Polyunsaturated Fatty Acids in Chicken Muscle Is Not Affected by Dietary Selenium, Vitamin E, or Corn Oil

We previously showed enrichments of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) in broiler chicks fed defatted microalgae. The aims of this study were to determine 1) if the enrichments affected meat texture and were enhanced by manipulating dietary corn oil, selenium, and vitamin E concentrations and 2) how the enrichments corroborated with hepatic gene expression involved in biosynthesis and oxidation of EPA and DHA. Day-old hatching Cornish Giant cockerels (n= 216) were divided into 6 groups (6 cages/group and 6 chicks/cage). Chicks were fed 1 of the 6 diets: a control diet containing 4% corn oil, 25 IU vitamin E/kg, and 0.2 mg Se/kg (4CO), 4CO + 10% microalgae (defatted Nannochloropsis oceanica; 4CO+ MA), 4CO+ MA – 2% corn oil (2CO+MA), 2CO+MA + 75 IU vitamin E/kg (2CO+MA+E), 2CO+MA + 0.3 mg Se/kg (2CO+MA+Se), and 2CO+MA+E + 0.3 mg Se/kg (2CO+MA+E+Se). After 6 wk, fatty acid profiles, DHA and EPA biosynthesis and oxidation, gene expression, lipid peroxidation, antioxidant status, and meat texture were measured in liver, muscles, or both. Compared with the control diet, defatted microalgae (4CO+MA) enriched (P< 0.05) DHA and EPA by ≤116 and 24 mg/100 g tissue in the liver and muscles, respectively, and downregulated (41–76%, P< 0.01) hepatic mRNA abundance of 4 cytochrome P450 (CYP) enzymes (CYP2C23b, CYP2D6, CYP3A5, CYP4V2). Supplemental microalgae decreased (50–82%, P< 0.05) lipid peroxidation and improved (16–28%, P< 0.05) antioxidant status in the liver, muscles, or both. Furthermore, the microalgae-mediated enrichments in the muscles were not elevated by altering dietary corn oil, vitamin E, or selenium and did not affect meat texture. The microalgae-mediated enrichments of DHA and EPA in the chicken muscles were associated with decreased hepatic gene expression of their oxidation, but were not further enhanced by altering dietary corn oil, vitamin E, or selenium.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2017

Digestibility of the defatted microalgae Nannochloropsis sp. and Desmodesmus sp. when fed to Atlantic salmon, Salmo salar

The aim of the study was to investigate the apparent digestibility coefficient (ADC) of defatted biomass derived from microalgae Nannochloropsis sp. and Desmodesmus sp. when fed to Atlantic salmon postsmolts in seawater. Two experiments, one employing cold-pelleted and the other employing extruded pellets, were carried out to determine the ADC of dry matter (DM), protein, ash and energy. The test feeds consisted of a fishmeal-based reference feed and the algal biomass, at a ratio of 70:30, and yttrium oxide as the inert marker. The ADC of DM and protein in fish fed microalgae-incorporated cold-pelleted feeds were significantly higher for Nannochloropsis sp. compared with Desmodesmus sp. Here, the Nannochloropsis sp. inclusion in extruded feeds also led to higher ADCs of DM and energy compared with Desmodesmus sp. The extrusion processing significantly increased the ADC of ash in both defatted microalgae biomass, as well as ADCs of DM in Nannochloropsis and protein in Desmodesmus sp. In conclusion, the microalga Nannochloropsis sp. was more digestible than Desmodesmus sp., and extrusion processing can be used as a means to improve digestibility of certain nutrients.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2016

Potential land competition between open-pond microalgae production and terrestrial dedicated feedstock supply systems in the U.S.

Biofuels produced from both terrestrial and algal biomass feedstocks can contribute to energy security while providing economic, environmental, and social benefits. To assess the potential for land competition between these two feedstock types in the United States, we evaluate a scenario in which 41.5 x 109 L yr-1 of second-generation biofuels are produced on pastureland, the most likely land base where both feedstock types may be deployed. This total includes 12.0 x 109 L yr-1 of biofuels from open-pond microalgae production and 29.5 x 109 L yr-1 of biofuels from terrestrial dedicated feedstock supply systems. Under these scenarios, open-pond microalgae production is projected to use 1.2 million ha of private pastureland, while terrestrial dedicated feedstock supply systems would use 14.0 million ha of private pastureland. A spatial meta-analysis indicates that potential competition for land under these scenarios would be concentrated in 110 counties, containing 1.0 and 1.7 million hectares of algal and terrestrial dedicated feedstock production, respectively. A land competition index applied to these 110 counties suggests that 38 to 59 counties could experience competition for upwards of 40% of a county’s pastureland. However, this combined 2.7 million ha represents only 2%-5% of total pastureland in the U.S., with the remaining 12.5 million ha of algal or terrestrial dedicated feedstock production on pastureland in non-competing areas.

agricultural policy analysis↗
DOE OSTI2014

An integrated assessment of location-dependent scaling for microalgae biofuel production facilities

Successful development of a large-scale microalgae-based biofuels industry requires comprehensive analysis and understanding of the feedstock supply chain—from facility siting and design through processing and upgrading of the feedstock to a fuel product. The evolution from pilot-scale production facilities to energy-scale operations presents many multi-disciplinary challenges, including a sustainable supply of water and nutrients, operational and infrastructure logistics, and economic competitiveness with petroleum-based fuels. These challenges are partially addressed by applying the Integrated Assessment Framework (IAF) – an integrated multi-scale modeling, analysis, and data management suite – to address key issues in developing and operating an open-pond microalgae production facility. This is done by analyzing how variability and uncertainty over space and through time affect feedstock production rates, and determining the site-specific “optimum” facility scale to minimize capital and operational expenses. This approach explicitly and systematically assesses the interdependence of biofuel production potential, associated resource requirements, and production system design trade-offs. To provide a baseline analysis, the IAF was applied in this paper to a set of sites in the southeastern U.S. with the potential to cumulatively produce 5 billion gallons per year. Finally, the results indicate costs can be reduced by scaling downstream processing capabilities to fit site-specific growing conditions, available and economically viable resources, and specific microalgal strains.

09 BIOMASS FUELS↗
DOE OSTI2024

Chapter 7.1: Microalgae

Microalgae is a unique biomass resource that does not need to compete for land and water with other biomass feedstocks because it can be cultivated on low-quality unencumbered land using noncompetitive water types including saline and wastewater. It is included as a complementary resource alongside other biomass feedstocks reported in this study, albeit at higher biomass production costs reflective of more capital-intensive farming operations than typical for terrestrial biomass. Higher biomass costs can be offset by the potential to produce value-added coproducts unique to compositional constituents of microalgae. Relative to BT16, this chapter reflects the latest analysis from the 2022 Algae Harmonization Update, which uses the latest parameterized and high-performing saline algal strain, second-generation carbon capture of point-source waste CO2 and high-pressure pipeline transport resolved to specific point-source types, saline water sourcing up to 40,000 mg/L total dissolved solids for source and makeup water salinity, blowdown water treatment and recycle, and brine disposal handling. National-scale algal biomass availability potential was calculated at 152 million tons/yr ash-free dry weight (AFDW) (191 million tons/yr dry weight) at an average biomass productivity of 26.2 g/m2 -day AFDW (about 50 tons/acre/yr dry weight).1 The algal biomass was cultivated on 3.9 million acres of multi-criteria screened and potentially available land for CONUS and fixed 268 million tons of waste CO2 based on biomass uptake. The algae biomass can be produced at an average MBSP of $674/ton AFDW ($536/ton dry weight) in 2020 dollars,2 corresponding to a total energy potential of 3.3 quads/yr at an average MBSP of $31.2/MMBtu (higher-heating-value [HHV] basis).

algae↗
DOE OSTI2020

Microalgae as a future food source

One of the key challenges that we face in the 21st century is the need to feed an ever-increasing human population with increasingly limited natural resources. Even today it is estimated that roughly 1 out of 9 people in the world are undernourished, of which the most important factor is protein-energy malnutrition. By establishing microalgae as a new food and feed platform, we have the opportunity to increase the supply of these essential products to address global demands in a more efficient and environmentally sustainable way. Many types of algae are nutritionally complete foods, their yields outperform most plant crops, and there is a growing set of tools to develop improved strains of algae. Similar improvements were achieved in traditional crops through thousands of years of breeding and strain selection, whereas with the newest genetic engineering tools and advanced strain selection techniques, similar changes can be implemented in microalgae in just a few years. Here we describe different strategies that could be used to enhance the nutritional content, productivity, and organoleptic traits of algae to help drive development of this new crop. Clearly developing more efficient, sustainable, and nutritious foods and feed would be an enormous benefit for the planet, and algae represents an opportunity to develop a new crop that would complement traditional agriculture, and one that could potential result in a more efficient means to meet the world's food and feed supply.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2018

Effect of microalgae cell composition and size on responsiveness to ultrasonic harvesting

Ultrasonic harvesting could reduce the energy consumption and costs associated with separating microalgae from growth media. The responsiveness of microalgae cells to an ultrasonic standing wave depends on the cell radius and acoustic contrast factor (ACF). The ACF can vary as cell composition (e.g. lipid, protein, carbohydrate content) varies depending on the algae strain, cultivation conditions, and growth stage. Here, two independent experimental methods were used to characterize the ACF of three algae ;strains—Nannochloropsis salina, Chlamydomonas reinhardtii, and Tetraselmis chuii—as a function of dynamic cellular composition over 9- to 14-day growth periods. For N. salina, lipid content increased from 25 ± 1% to 33 ± 1% ash-free dry weight (AFDW) and ACF decreased by 46% (from 0.041 ± 0.002 to 0.022 ± 0.002) between growth days 3 and 10. For C. reinhardtii, lipid content increased from 26 ± 1% to 40 ± 1% AFDW and ACF decreased by 33% (from 0.051 ± 0.013 to 0.034 ± 0.006) between growth days 3 and 9. For T. chuii, lipid content and ACF remained stable (~ 10% AFDW and ~ 0.3) over the growth period. ACF decreased as lipid content increased because lipids have a negative ACF in the growth media; however, cell size had a greater impact on cell responsiveness because the ratio of the acoustic radiation force to the drag force is proportional to cell radius squared.

09 BIOMASS FUELS↗
DOE OSTI2020

Balancing Water Sustainability and Productivity Objectives in Microalgae Cultivation: Siting Open Ponds by Considering Seasonal Water-Stress Impact Using AWARE-US

Microalgae have great potential as an energy crop. Scaling-up algal biofuel production in the United States (US) should be done with careful attention to water stress. This study evaluates the regional and seasonal water-stress impact of potential algae-pond deployments in the US. Three site-selection strategies focusing on biomass yield, water-use efficiency (WUE), and water-stress impact, respectively, are applied and compared to meet a US algae biomass production target of 30 million metric tons/yr ash-free dry weight, which converts to 20.8 billion L renewable diesel, via hydrothermal liquefaction. Ranking algae ponds based on biomass yield leads to freshwater consumption of 2.66 km3/yr, resulting in the highest water-stress impact (39.1 US equivalent km3). Under the WUE scenario, water consumption is reduced by 81%, but biomass yield is reduced by 12%. In contrast, adding a water-stress constraint to the biomass-yield ranking reduces water consumption by 50% and water-stress impact by 97%, with a small yield reduction (1.7%). Results show that pond location has a significant effect on water stress and that water stress is not proportional to water consumption or yield. Furthermore, capturing seasonal water patterns is critical for planning because sites in water-abundant regions can have short-term but significant water-stress impacts.

algae, Biofuel, water scarcity footprint, hydrothe↗