scholarly journals The Dark Side of Microalgae Biotechnology: A Heterotrophic Biorefinery Platform Directed to ω-3 Rich Lipid Production

2019 ◽  
Vol 7 (12) ◽  
pp. 670 ◽  
Author(s):  
Teresa Lopes da Silva ◽  
Patrícia Moniz ◽  
Carla Silva ◽  
Alberto Reis
Keyword(s):  
Low Cost ◽  
Lipid Production ◽  
Arable Land ◽  
Integrated System ◽  
Dark Side ◽  
Omega 3 ◽  
Niche Markets ◽  
Microalgal Biomass ◽  
Oleaginous Microalgae ◽  
Heterotrophic Microalgae

Microbial oils have been considered a renewable feedstock for bioenergy not competing with food crops for arable land, freshwater and biodiverse natural landscapes. Microalgal oils may also have other purposes (niche markets) besides biofuels production such as pharmaceutical, nutraceutical, cosmetic and food industries. The polyunsaturated fatty acids (PUFAs) obtained from oleaginous microalgae show benefits over other PUFAs sources such as fish oils, being odorless, and non-dependent on fish stocks. Heterotrophic microalgae can use low-cost substrates such as organic wastes/residues containing carbon, simultaneously producing PUFAs together with other lipids that can be further converted into bioenergy, for combined heat and power (CHP), or liquid biofuels, to be integrated in the transportation system. This review analyses the different strategies that have been recently used to cultivate and further process heterotrophic microalgae for lipids, with emphasis on omega-3 rich compounds. It also highlights the importance of studying an integrated process approach based on the use of low-cost substrates associated to the microalgal biomass biorefinery, identifying the best sustainability methodology to be applied to the whole integrated system.

scholarly journals Biomass and lipid induction strategies in microalgae for biofuel production and other applications

2019 ◽  
Vol 18 (1) ◽  
Author(s):  
Hossein Alishah Aratboni ◽  
Nahid Rafiei ◽  
Raul Garcia-Granados ◽  
Abbas Alemzadeh ◽  
José Rubén Morones-Ramírez
Keyword(s):  
Lipid Content ◽  
Large Scale ◽  
Fossil Fuels ◽  
Low Cost ◽  
Lipid Production ◽  
Arable Land ◽  
Economic Cost ◽  
Biofuel Production ◽  
Scale Production ◽  
Microalgae Biomass

Abstract The use of fossil fuels has been strongly related to critical problems currently affecting society, such as: global warming, global greenhouse effects and pollution. These problems have affected the homeostasis of living organisms worldwide at an alarming rate. Due to this, it is imperative to look for alternatives to the use of fossil fuels and one of the relevant substitutes are biofuels. There are different types of biofuels (categories and generations) that have been previously explored, but recently, the use of microalgae has been strongly considered for the production of biofuels since they present a series of advantages over other biofuel production sources: (a) they don’t need arable land to grow and therefore do not compete with food crops (like biofuels produced from corn, sugar cane and other plants) and; (b) they exhibit rapid biomass production containing high oil contents, at least 15 to 20 times higher than land based oleaginous crops. Hence, these unicellular photosynthetic microorganisms have received great attention from researches to use them in the large-scale production of biofuels. However, one disadvantage of using microalgae is the high economic cost due to the low-yields of lipid content in the microalgae biomass. Thus, development of different methods to enhance microalgae biomass, as well as lipid content in the microalgae cells, would lead to the development of a sustainable low-cost process to produce biofuels. Within the last 10 years, many studies have reported different methods and strategies to induce lipid production to obtain higher lipid accumulation in the biomass of microalgae cells; however, there is not a comprehensive review in the literature that highlights, compares and discusses these strategies. Here, we review these strategies which include modulating light intensity in cultures, controlling and varying CO2 levels and temperature, inducing nutrient starvation in the culture, the implementation of stress by incorporating heavy metal or inducing a high salinity condition, and the use of metabolic and genetic engineering techniques coupled with nanotechnology.

scholarly journals Overexpression of an endogenous type 2 diacylglycerol acyltransferase in the marine diatom Phaeodactylum tricornutum enhances lipid production and omega-3 Long Chain Polyunsaturated Fatty Acid content

2020 ◽  
Author(s):  
Richard P. Haslam ◽  
Mary L. Hamilton ◽  
Chloe K. Economou ◽  
Richard Smith ◽  
Kirsty L. Hassall ◽  
...  
Keyword(s):  
Metabolic Engineering ◽  
Phaeodactylum Tricornutum ◽  
Lipid Production ◽  
Marine Diatom ◽  
Efficient Production ◽  
Omega 3 ◽  
Oleaginous Microalgae ◽  
Epa And Dha ◽  
Long Chain

Abstract Background: Oleaginous microalgae represent a valuable resource for the production of high value molecules. Considering the importance of omega-3 long chain polyunsaturated fatty acids (LC-PUFAs) for human health and nutrition the yields of high value eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) require significant improvement to meet demand, however, the current cost of production remains high. A promising approach is to metabolically engineer strains with enhanced levels of triacylglycerols (TAGs) enriched in EPA and DHA.Results: Recently we have engineered the marine diatom Phaeodactylum tricornutum to accumulate enhanced levels of DHA in TAG. To further improve the incorporation of omega-3 LC-PUFAs in TAG we focused our effort on the identification of a type 2 acyl-CoA:diacylglycerol acyltransferase (DGAT) capable of improving lipid production and the incorporation of DHA in TAG. DGAT is a key enzyme in lipid synthesis. Following a diatom based in vivo screen of candidate DGATs, a native P. tricornutum DGAT2B was taken forward for detailed characterisation. Overexpression of the endogenous P. tricornutum DGAT2B was confirmed by qRT-PCR and the transgenic strain grew successfully in comparison to wildtype. PtDGAT2B has broad substrate specificity with preferences for C16 and LC-PUFAs acyl groups. Moreover, the overexpression of an endogenous DGAT2B resulted in higher lipid yields and enhanced levels of DHA in TAG. Furthermore, a combined overexpression of the endogenous DGAT2B and ectopic expression of a Δ5-elongase showed how iterative metabolic engineering can be used to increase DHA and TAG content, irrespective of nitrogen treatment.Conclusion: This study provides further insight into lipid metabolism in P. tricornutum and suggests a metabolic engineering approach for the efficient production of EPA and DHA in microalgae.

scholarly journals The Role of Heterotrophic Microalgae in Waste Conversion to Biofuels and Bioproducts

Processes ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 1090
Author(s):  
Teresa Lopes da Silva ◽  
Patrícia Moniz ◽  
Carla Silva ◽  
Alberto Reis
Keyword(s):  
Unsaturated Fatty Acids ◽  
Waste Treatment ◽  
Culture Media ◽  
Low Cost ◽  
Algal Growth ◽  
Value Added ◽  
Production Costs ◽  
Microalgal Biomass ◽  
Heterotrophic Microalgae ◽  
Wide Range

In the last few decades, microalgae have attracted attention from the scientific community worldwide, being considered a promising feedstock for renewable energy production, as well as for a wide range of high value-added products such as pigments and poly-unsaturated fatty acids for pharmaceutical, nutraceutical, food, and cosmetic markets. Despite the investments in microalgae biotechnology to date, the major obstacle to its wide commercialization is the high cost of microalgal biomass production and expensive product extraction steps. One way to reduce the microalgae production costs is the use of low-cost feedstock for microalgae production. Some wastes contain organic and inorganic components that may serve as nutrients for algal growth, decreasing the culture media cost and, thus, the overall process costs. Most of the research studies on microalgae waste treatment use autotrophic and mixotrophic microalgae growth. Research on heterotrophic microalgae to treat wastes is still scarce, although this cultivation mode shows several benefits over the others, such as higher organic carbon load tolerance, intracellular products production, and stability in production all year round, regardless of the location and climate. In this review article, the use of heterotrophic microalgae to simultaneously treat wastes and produce high value-added bioproducts and biofuels will be discussed, critically analyzing the most recent research done in this area so far and envisioning the use of this approach to a commercial scale in the near future.

scholarly journals Overexpression of a type 2 diacylglycerol acyltransferase in the marine diatom Phaeodactylum tricornutum enhances lipid production and omega-3 Long Chain Polyunsaturated Fatty Acid content

2020 ◽  
Author(s):  
Richard P. Haslam ◽  
Mary L. Hamilton ◽  
Chloe K. Economou ◽  
Richard Smith ◽  
Kirsty L. Hassall ◽  
...  
Keyword(s):  
Metabolic Engineering ◽  
Phaeodactylum Tricornutum ◽  
Lipid Production ◽  
Marine Diatom ◽  
Efficient Production ◽  
Omega 3 ◽  
Oleaginous Microalgae ◽  
Epa And Dha ◽  
Long Chain

Abstract Background: Oleaginous microalgae represent a valuable resource for the production of high value molecules. Considering the importance of omega-3 long chain polyunsaturated fatty acids (LC-PUFAs) for human health and nutrition the yields of high value eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) require significant improvement to meet demand, however, the current cost of production remains high. A promising approach is to metabolically engineer strains with enhanced levels of triacylglycerols (TAGs) enriched in EPA and DHA. Results: Recently we have engineered the marine diatom Phaeodactylum tricornutum to accumulate enhanced levels of DHA in TAG. To further improve the incorporation of omega-3 LC-PUFAs in TAG we focused our effort on the identification of a type 2 acyl-CoA:diacylglycerol acyltransferase (DGAT) capable of improving lipid production and the incorporation of DHA in TAG. DGAT is a key enzyme in lipid synthesis. Following a diatom based in vivo screen of candidate DGATs, a native P. tricornutum DGAT2B was taken forward for detailed characterisation. Expression of DGAT2B in P. tricornutum was confirmed by qRT-PCR and the transgenic strain grew successfully in comparison to wildtype. PtDGAT2B has broad substrate specificity with preferences for C16 and LC-PUFAs acyl groups. Moreover, the expression of DGAT2B resulted in higher lipid yields and enhanced levels of DHA in TAG. Furthermore, co-expression with a Δ5-elongase showed how iterative metabolic engineering can be used to increase DHA and TAG content, irrespective of nitrogen treatment.Conclusion: This study provides further insight into lipid metabolism in P. tricornutum and suggests a metabolic engineering approach for the efficient production of EPA and DHA in microalgae.

scholarly journals Microwave-Assisted Brine Extraction for Enhancement of the Quantity and Quality of Lipid Production from Microalgae Nannochloropsis sp.

Molecules ◽  
2019 ◽  
Vol 24 (19) ◽  
pp. 3581 ◽  
Author(s):  
Zghaibi ◽  
Omar ◽  
Kamal ◽  
Biak ◽  
Harun
Keyword(s):  
Fatty Acids ◽  
Low Cost ◽  
Methyl Esters ◽  
Lipid Production ◽  
Lipid Extraction ◽  
Soxhlet Extraction ◽  
Solid Loading ◽  
Omega 3 ◽  
Microwave Assisted

Toward attaining a sustainability and eco-friendly process, a green and low-cost solvent—brine (NaCl solution) is proposed, as microwave-assisted extraction (MAE) technique solvent to extract lipids from microalgae Nannochloropsis sp. The effect of NaCl concentration on the quantity and quality of the extracted lipid was assessed, while MAE parameters were optimized using response surface methodology (RSM). The content of fatty acid methyl esters (FAMEs) in the lipid was analyzed by using a gas chromatography—flame ionization detector (GC/FID). The highest lipid yield (16.1%) was obtained using 10% (w/v) brine at optimum extraction parameters of 5% (w/v) solid loading, 100 °C, and 30 min. The lipid extraction yield via optimized MAE-brine technique was thrice better than that Soxhlet extraction did and only 2% less than Bligh and Dyer (B&D) lipid extraction, which utilized harmful solvents. The proposed MAE-brine technique offered better quality lipids containing the highest amount of polyunsaturated fatty acids (PUFA) (44.5%) and omega-3 fatty acids (FAs) (43%). Hence, the MAE-brine solvent technique appears to be a promising extraction method for cheaper, greener, and faster extraction of a high-quality lipid for specialty food applications.

scholarly journals Year-Round Cultivation of Tetraselmis sp. for Essential Lipid Production in a Semi-Open Raceway System

Marine Drugs ◽  
2021 ◽  
Vol 19 (6) ◽  
pp. 314
Author(s):  
Won-Kyu Lee ◽  
Yong-Kyun Ryu ◽  
Woon-Yong Choi ◽  
Taeho Kim ◽  
Areumi Park ◽  
...  
Keyword(s):  
Lipid Content ◽  
Essential Fatty Acids ◽  
Lipid Production ◽  
Biomass Productivity ◽  
Information Modeling ◽  
Photon Flux ◽  
Climatic Data ◽  
Omega 3 ◽  
Microalgal Biomass ◽  
Omega 6

There is increasing demand for essential fatty acids (EFAs) from non-fish sources such as microalgae, which are considered a renewable and sustainable biomass. The open raceway system (ORS) is an affordable system for microalgae biomass cultivation for industrial applications. However, seasonal variations in weather can affect biomass productivity and the quality of microalgal biomass. The aim of this study was to determine the feasibility of year-round Tetraselmis sp. cultivation in a semi-ORS in Korea for biomass and bioactive lipid production. To maximize biomass productivity of Tetraselmis sp., f medium was selected because it resulted in a significantly higher biomass productivity (1.64 ± 0.03 g/L) and lower omega-6/omega-3 ratio (0.52/1) under laboratory conditions than f/2 medium (0.70/1). Then, we used climatic data-based building information modeling technology to construct a pilot plant of six semi-ORSs for controlling culture conditions, each with a culture volume of 40,000 L. Over 1 year, there were no significant variations in monthly biomass productivity, fatty acid composition, or the omega-6/omega-3 ratio; however, the lipid content correlated significantly with photosynthetic photon flux density. During year-round cultivation from November 2014 to October 2017, areal productivity was gradually increased by increasing medium salinity and injecting CO2 gas into the culture medium. Productivity peaked at 44.01 g/m2/d in October 2017. Throughout the trials, there were no significant differences in average lipid content, which was 14.88 ± 1.26%, 14.73 ± 2.44%, 12.81 ± 2.82%, and 13.63 ± 3.42% in 2014, 2015, 2016, and 2017, respectively. Our results demonstrated that high biomass productivity and constant lipid content can be sustainably maintained under Korean climate conditions.

scholarly journals The Role of Trees and Pastures in Organic Agriculture

2015 ◽  
Vol 4 (3) ◽  
pp. 51 ◽  
Author(s):  
Joseph R. Heckman
Keyword(s):  
Soil Erosion ◽  
Soil Carbon ◽  
Organic Farming ◽  
Arable Land ◽  
Organic Matter Content ◽  
United States Department ◽  
Omega 3 ◽  
Row Crops ◽  
Tree Crops ◽  
Organic Farm

<p>Environmental concerns associated with annual row crop grain production – including soil erosion, soil carbon loss, intensive use of chemicals and petroleum, limited arable land, among others – could be addressed by converting conventional livestock production to an organic pasture based system. The inclusion of tree crops would further enhance the opportunity for feeding pasture- raised livestock by providing shelter and alternative feed sources. Biodiversity is an essential aspect of an organic farm plan. The idea of including tree crops and other perennials into the vision of an organic farm as a “living system” is very much compatible with the goals and philosophy of organic farming. Before modern no-till farming systems were developed, tree crops and pasture systems were found to provide similar benefits for controlling soil erosion and conserving soil carbon. For example, J. Russell Smith’s <em>Tree Crops: A Permanent Agriculture</em> (Smith, 1950) and pioneered tree crop agriculture as the alternative to annual row crops for protecting soils from erosion while producing livestock feed such as acorns, nuts, and fodder. A survey of Mid-Atlantic USA soils under pasture found 60% higher soil organic matter content than cultivated fields. Because United States Department of Agriculture’s National Organic Program (USDA-NOP) standards require dairy cattle consume pasture forage and limited grain (7 C.F.R. pt. 206), organic milk contains higher concentrations of omega-3 and fewer omega-6 fatty acids than conventional milk. Organic standards also state “the producer must not use lumber treated with arsenate or other prohibited materials for new [fence posts] installations or replacement purposes in contact with soil or livestock.” Black locust (<em>Robinia pseudoacacia</em>) is a fast growing renewable alternative to treated lumber with many attributes compatible with organic farming. This versatile tree fixes nitrogen (N), provides flowers for honey bees and other pollinators, and produces a highly durable dense wood ideal for fence posts useable for up to 50 year.</p>

Biophotolysis-based hydrogen and lipid production by oleaginous microalgae using crude glycerol as exogenous carbon source

2017 ◽  
Vol 42 (4) ◽  
pp. 1970-1976 ◽  
Author(s):  
Dennapa Sengmee ◽  
Benjamas Cheirsilp ◽  
Thanwadee Tachapattaweawrakul Suksaroge ◽  
Poonsuk Prasertsan
Keyword(s):  
Carbon Source ◽  
Crude Glycerol ◽  
Lipid Production ◽  
Oleaginous Microalgae ◽  
Exogenous Carbon Source

scholarly journals Correction: Low-cost lipid production by an oleaginous yeast cultured in non-sterile conditions using model waste resources

2014 ◽  
Vol 7 (1) ◽  
pp. 42 ◽  
Author(s):  
Fabio Santomauro ◽  
Fraeya M Whiffin ◽  
Rod J Scott ◽  
Christopher J Chuck
Keyword(s):  
Oleaginous Yeast ◽  
Low Cost ◽  
Lipid Production
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