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A possibility of obtaining the micro- and macroparameters of a microalgae oil spray very similar to that of a diesel fuel as well as of ensuring the good level of their correspondence within a wide range of injection pressures distinct from mechanical fuel injection systems (800–1400 bar) and common rail direct injection systems (2000–2500 bar) will definitely lead to the fact that microalgae oil is at or very near commercialization. In this study, mathematical equations proposed by Lyshevsky and later approved by Razleytcev and Kuleshov were further rearranged to obtain dimensionless parameters capable of characterizing the variation of the integral liquid "core" length of a microalgae oil spray, the integral Sauter mean diameter, and the integral spray cone half-angle tangent for a broad range of injection pressures and preheating temperatures. At high fuel injection pressures and ambient temperature, the evolution of microalgae oil spray was completely different from the baseline mineral diesel, suggesting its far worse fuel atomization with a 41–49% larger droplet size distribution, a 40–58% narrower spray cone angle, and a 307–419% longer distance from the exit of the nozzle to the break-up point. We propose a method that allows variations in relational expressions of the spray-describing variables to be considered as part of the injection process capability study. A temperature interval of 105–115°C was found to ensure the correspondence of micro- and macroparameters of the microalgae oil spray vis-a-vis diesel fuel spray (20 °C) with a high level of precision (r = 0.91–1.0) for both the MFI and CRDI systems. [ABSTRACT FROM AUTHOR]

In this study, it is demonstrated that natural microalgae oils, which contain fatty acid components including docosahexaenoic acid (DHA), could be directly applied to fabricate vesicular structures in aqueous phase through a forced formation process. The microalgae oil vesicles had initial average diameters of 170-230 nm with negative charges apparently caused by dissociation of the fatty acid components. The vesicles possessed excellent stability with lifetimes for at least 450 days. The formation of the vesicular structures with hydrophilic cores/regions was confirmed by the transmission electron microscopy (TEM) image and successful encapsulation of a hydrophilic material. For encapsulation of a hydrophobic material, lutein, the vesicle size was increased probably due to the insertion of lutein into the hydrophobic vesicular bilayer structures. The analysis of Fourier transform infrared (FTIR) spectroscopy suggested that the vesicular bilayer fluidity was decreased by encapsulating lutein. However, the lutein-encapsulating microalgae oil vesicles still possessed high stability and the vesicular structures could maintain intact even at an environmental temperature up to 60°C. Applicability of the microalgae oil vesicles as drug delivery carriers was also demonstrated by successful encapsulation of curcumin. However, when the loaded curcumin was increased to a certain amount, physical stability of the microalgae oil vesicles was significantly reduced. This is probably because the vesicular structures with only limited spaces for accommodating hydrophobic materials were strongly affected by encapsulating a large amount of curcumin. It is interesting to note that by adding egg L-α-phosphatidylcholine, the curcumin encapsulation-induced instability of the microalgae oil vesicles could be alleviated. The results indicated that vesicular structures could be fabricated from microalgae oils and the microalgae oil vesicles were capable of encapsulating hydrophilic or hydrophobic materials for drug delivery applications. The findings lay a background for further dosage form development of nutritional supplements encapsulated by natural microalgae oils. [ABSTRACT FROM AUTHOR]

Petrodiesel is an unsustainable and undependable fuel owing to its environmental concerns and depleting reserves. Biodiesel is a sustainable alternative fuel to petrodiesel with a better fuel quality and minimum environmental impacts. However, cost-effective biodiesel production requires the use of a sustainable feedstock and process optimization. This study explored biodiesel yield optimization from mixed microalgae oil (MO) and waste cooking oil (WCO). The use of mixed feedstock for biodiesel production relieves the rising demands; lowers feedstock costs; and improves the fuel quality, engine performance, and pollutants emission characteristics. MO was extracted from dried microalgae biomass by the Soxhlet method using hexane. The MO and WCO were purified and characterized, and an oil blend with suitable properties (best in kinematic viscosity, density, higher heating value, and acid value compared to other blends) was selected. The transesterification experiments designed by central composite design were optimized using the response surface methodology. Experimental results underwent regression analysis to develop a quadratic model equation for predicting the optimum level of parameters and biodiesel yield. Model fitness and variables effects on biodiesel yield were studied using analysis of variance. The optimization experiment achieved 98.82% oil conversion rate at the catalyst loading of 2.0 w/v%, molar ratio of 12:1 v/v, reaction temperature of 60 ℃, and reaction time of 100 min. A triplicate validation experiments achieved 97.72% conversion rate, which is very close to the model predicted result (99.1%). Biodiesel from MO-WCO showed a better cetane number (77.76), iodine value (12.90 gI2/100 g), acid value (0.049 mg KOH/g), HHV (43.25 MJ/kg), kinematic viscosity (4.50 mm2/s), pour point (–2.5 ℃), and flash point (180 ℃). In conclusion, the study revealed that transesterification of blended MO-WCO led to a maximum biodiesel and the reaction time and temperature were found to be the most significant factors affecting the yield of biodiesel. Furthermore, biodiesel from blended MO-WCO is a sustainable and environmentally friendly alternative fuel source which can contribute towards a promising industrial scale biodiesel production in the future.

Petrodiesel is an unsustainable and undependable fuel owing to its environmental concerns and depleting reserves. Biodiesel is a sustainable alternative fuel to petrodiesel with a better fuel quality and minimum environmental impacts. However, cost-effective biodiesel production requires the use of a sustainable feedstock and process optimization. This study explored biodiesel yield optimization from mixed microalgae oil (MO) and waste cooking oil (WCO). The use of mixed feedstock for biodiesel production relieves the rising demands; lowers feedstock costs; and improves the fuel quality, engine performance, and pollutants emission characteristics. MO was extracted from dried microalgae biomass by the Soxhlet method using hexane. The MO and WCO were purified and characterized, and an oil blend with suitable properties (best in kinematic viscosity, density, higher heating value, and acid value compared to other blends) was selected. The transesterification experiments designed by central composite design were optimized using the response surface methodology. Experimental results underwent regression analysis to develop a quadratic model equation for predicting the optimum level of parameters and biodiesel yield. Model fitness and variables effects on biodiesel yield were studied using analysis of variance. The optimization experiment achieved 98.82% oil conversion rate at the catalyst loading of 2.0 w/v%, molar ratio of 12:1 v/v, reaction temperature of 60 ℃, and reaction time of 100 min. A triplicate validation experiments achieved 97.72% conversion rate, which is very close to the model predicted result (99.1%). Biodiesel from MO-WCO showed a better cetane number (77.76), iodine value (12.90 gI2/100 g), acid value (0.049 mg KOH/g), HHV (43.25 MJ/kg), kinematic viscosity (4.50 mm2/s), pour point (–2.5 ℃), and flash point (180 ℃). In conclusion, the study revealed that transesterification of blended MO-WCO led to a maximum biodiesel and the reaction time and temperature were found to be the most significant factors affecting the yield of biodiesel. Furthermore, biodiesel from blended MO-WCO is a sustainable and environmentally friendly alternative fuel source which can contribute towards a promising industrial scale biodiesel production in the future. [ABSTRACT FROM AUTHOR]

The ability to manage the liquid jet atomization and the breakup of droplets in diesel engines is becoming now one of the most important challenges of the unmodified CI engines' operations. A mature comparative analysis is performed to achieve enhancement of the injection and liquid jet breakup characteristics of microalgae oil (MAO100) at an elevated temperature of up to 80 °C. To obtain reliable data, the following experimental tasks were performed and qualitatively described to identify the (i) distribution of Sauter mean diameter (SMD) d32 of fuel droplets within the temporal evolution of a fuel jet, (ii) dynamics and topology dependencies of the liquid jet atomization and droplet breakup, (iii) dynamic formation of the liquid jet structure, and (iv) character and peculiarities of liquid jet breakup. The results of the research have shown the presence of zones distinguished by very intense droplet breakup, which carried out a robust individual character that does not depend on the type and temperature of the fuel. Furthermore, the preheated MAO100 was dominant (~ 70%) with droplets of the following size, d ≤ 40–50 μm (~ 20%) and d ≤ 120 μm (~ 50%), who were 1.2 to 1.5 smaller compared to those obtained at 20 °C. At t = 2 ms after injection of MAO100 (80 °C), the presence of droplets which radiuses exceed 500 μm was prevented. This tendency is ideally comparable to the one for a diesel fuel that, in turn, supports the hypothesis that the physical contribution to the ignition delay and hence to the entire process of combustion could be effectively controlled by the preheating route. [ABSTRACT FROM AUTHOR]

This study aims to investigate the optimized lipase-catalysed esterification reaction from novel feedstock microalgae (Chlorella protothecoides) oil-free fatty acids (FFAs) for biolubricant (Trimethylolpropane (TMP)-triesters) synthesis. FFAs were obtained from microalgae oil by enzymatic hydrolysis. Response surface methodology (RSM) with the central composite design was performed to investigate the effect of experimental factors (lipase amount, TMP/FFAs molar ratio, reaction temperature) on the FFAs conversion and also investigated to resolve the optimum design points. After the experimental studies, the highest FFAs conversion of 93% with 92% triester and 8% mono, di esters contents were found when the lipase amount was 5.5%. TMP/FFAs molar ratio was 0.33 and the reaction temperature value was 60°C. The model fitted with the experimental values with R2 = 0.97. It was also supported by gas chromatography and FTIR analyses that the product obtained was a lubricant. [ABSTRACT FROM AUTHOR]

Sustainable socio-economic development largely depends on the sustainability of the energy supply from economic, environmental, and public health perspectives. Fossil fuel combustion only meets the first element of this equation and is hence rendered unsustainable. Biofuels are advantageous from a public health perspective, but their environmental and economic sustainability might be questioned considering the conflicts surrounding their feedstocks, including land use change and fuel vs. food conflict. Therefore, it is imperative to put more effort into addressing the downsides of biofuel production using advanced technologies, such as nanotechnology. In light of that, this review strives to scrutinize the latest developments in the application of nanotechnology in producing biodiesel, a promising alternative to fossil diesel with proven environmental and health benefits. The main focus is placed on nanotechnology applications in the feedstock production stage. First, the latest findings concerning the application of nanomaterials as nanofertilizers and nanopesticides to improve the performance of oil crops are presented and critically discussed. Then, the most promising results reported recently on applying nanotechnology to boost biomass and oil production by microalgae and facilitating microalgae harvesting are reviewed and mechanistically explained. Finally, the promises held by nanomaterials to enhance animal fat production in livestock, poultry, and aquaculture systems are elaborated. Despite the favorable features of using nanotechnology in biodiesel feedstock production, the presence of nanoparticles in living systems is also associated with important health and environmental challenges, which are critically covered and discussed in this work.

Fish is an inexpensive source of high-quality protein as well as valuable micronutrients. Increasing the volume of fish and producing more fish feed is necessary to ensure the necessary consumption. One of the main components of fish feed is oil, the most crucial lipid source in fish feed. Fish oil is easily digestible and contains essential fatty acids, but replacing fish oil with alternative oil might make the fish feed more sustainable. Vegetable oils can replace fish oil due to reduced costs due to continued growth in production volumes, high availability and better economic value. Soy, linseed, rapeseed, sunflower, palm and olive oils are often used in fish feed. Also, microalgae oil is rich in essential fatty acids and a long-lasting alternative to fish oil. Important is not only the environmental impact of oil alternatives but also how these alternatives maintain or even improve the overall composition and quality of fish feed and products. An LCA assessment was performed to determine the environmental impact of microalgae, rapeseed oil, and fish oil. Where LCA system boundaries are "cradle to gate" and a functional unit of 1 kg of oil. LCA inventory is data from a literature review and SimaPro Ecoinvent database. The results obtained from LCA are based on PEFCR impact assessment categories. The LCA results show that the single score value for microalgae oil is 1.00E+00 mPt, for rapeseed oil 3.55E-01 mPt and fish oil 1.61E-01 mPt. It should be noted that the comparison presented reflects a generic comparison of alternatives, as the input data is derived from the literature analysis and the Ecoinvent v3.8 database. [ABSTRACT FROM AUTHOR]

Microalgae oil (MO) and styrene-butadiene-styrene block copolymer (SBS) were used as composite regenerants to blend into aged asphalt to prepare MO/SBS composite regenerated asphalt. The basic physical properties, high and low temperature rheological characteristics and fatigue characteristics of composite recycled asphalt were compared. The effects of the ratio and amount of MO and SBS on the regeneration effect of aged asphalt were investigated. The results showed that the viscoelastic deformation ability of pure MO recycled asphalt could recover to a certain extent to the level before aging, but there was still a certain gap. On this basis, MO/SBS composite regeneration could significantly improve the high-temperature deformation resistance and elastic recovery performance, and its critical temperature was 1.1~9.7 ℃ higher than that before aging. At the same time, it also reduced the sensitivity of recycled asphalt to fatigue strain to improve fatigue resistance. However, the low-temperature creep deformation ability of MO/SBS composite recycled asphalt was lower than that of base asphalt. When the mass fraction of MO and SBS were 8% and 4%, the composite recycled asphalt had better rheological and fatigue characteristics at high and low temperature.

Microalgae oil has great potential to address the growing energy demand and dependence on fossil fuels. However, the multilayered cell walls of microalgae hinder efficient extraction and enhanced lipid recovery. In this study, we develop a novel protocol based on near infrared-assisted extraction (NIRAE) technology to extract efficiently total lipids from Scenedesmus obliquus. Under a greener solvent extraction approach, the effect of nine non-polar/polar solvent systems in various ratios on lipid yield was tested, and the results were compared with Soxhlet, Folch, and Bligh–Dyer methods. The highest oil yields were NIRAE 15.43%, and Soxhlet 22.24%, using AcoEt/MeOH (1:2 v/v). For Folch and Bligh–Dyer, 9.11 and 10%, respectively. The optimized NIRAE conditions obtained using response surface methodology (RSM): 43.8 min, solvent/biomass 129.90:1 (m/v), and AcOEt/MeOH 0.57:2.43 (v/v) increased the oil yield significantly to 24.20%. In contrast to conventional methods, the overall optimized NIRAE process satisfied the requirements of a green extraction because of the simple and safe operation, less solvent toxicity, lower extraction time, and solvent and energy consumption. [ABSTRACT FROM AUTHOR]

Conventional homogeneous catalysts are non-biodegradable, requiring complicated downstream separation, further diminishing the overall economics. In this paper, a new heterogeneous catalyst, a metal-organic framework modified by biomaterials (Bio-MOF), complexed with an ionic liquid ([HMIM][HSO 4 ]/Bio-MOF), has been synthesized and integrated with microbubble mediated mass transfer technology to overcome the challenges of low conversion. The ionic liquid 1-methylimidazole hydrogen sulfate provides enhanced reactivity, while the Bio-MOF provides more active sites for the reaction. Detailed kinetic analysis suggests the biodiesel production reaction occurs on the vapor/liquid (microalgae oil) interface. The results revealed a higher conversion of (molar ratio of oil: methanol =1: 15, catalyst loading = 0.5 wt% of MO, temperature = 70 ºC) 92 ± 4% was achieved in 30 min relative to acid-catalyzed biodiesel production. Along with higher reactivity and larger surface area provided by the catalysts, the unprecedented higher conversion and rate of reaction is attributed to the "local" excess of alcohol present at the interface and simultaneous removal of water from the reactor. The results of activation energy (7.9 kJ mol−1), enthalpy (4.92 kJ mol−1), entropy (−287 J mol−1), and Gibbs free energy (103.58 kJ mol−1) show that current process required less energy is required for biodiesel production. The catalyst was recycled seven times and showed high stability with little reduction in its activity over these seven runs. The study demonstrates that this newly developed catalyst provides a high reaction rate and conversion of biodiesel production from microalgae oil using a heterogeneous catalyst by integrating it with microbubble-mediated mass transfer. [Display omitted] • Potential of microbubble technology being used to improve biorefinery development. • Wastewater treated with microalgae achieved EU standard discharge limit. • Maximum Chlorella vulgaris oil conversion using ([HMIM][HSO 4 ]/Bio-MOF) is 92 ± 4%. • The kinetics show esterification reaction occurs on the bubble/liquid interface. [ABSTRACT FROM AUTHOR]

ABSTRACT: The primary goal of this study was to investigate the effect of feeding White Leghorn hens graded levels of a docosahexaenoic acid (DHA)-rich microalgae oil (MAO) on productive performance and enrichment of eggs with very long-chain (VLC) omega-3 (n-3) polyunsaturated fatty acids (PUFA). Forty-nine-week-old hens (8 per diet) were fed the following diets for 28 d: 1) A corn-soybean meal-based diet with no supplemental oil (CON); 2) CON + 10 g/kg MAO; 3) CON + 20 g/kg MAO; 4) CON + 30 g/kg MAO; 5) CON + 40 g/kg MAO; 6) CON + 40 g/kg MAO + 20 g/kg high-oleic sunflower oil (HOSO); and 7) CON + 40 g/kg MAO + 40 g/kg HOSO. Diets 6 and 7 were included because we previously reported that co-feeding high-oleic acid oils with n-3 PUFA-containing oils attenuated egg yolk n-3 PUFA contents vs. feeding hens the n-3 oils alone. All data were collected on an individual hen basis. Egg VLC n-3 PUFA enrichment plateaued, in terms of statistical significance, at the 30 g/kg MAO level (266 mg/yolk). Hens fed 40 g/kg MAO had greatly attenuated measures of hen performance, marked liver enlargement, an altered ovarian follicle hierarchy, greatly lowered circulating triglyceride levels, and depressed hepatic expression of key genes involved in triglyceride synthesis and secretion. As compared to hens fed 40 g/kg MAO alone, feeding hens 40 g/kg MAO co-supplemented with HOSO (Diets 6 and 7) restored egg production, ovarian morphology, and all other measures of hen productive performance to CON levels, elevated plasma triglyceride levels, prevented liver enlargement, and increased the hepatic expression of key genes involved in triglyceride synthesis and secretion. In conclusion, MAO can greatly enrich hens’ eggs with VLC n-3 PUFA, but its recommended dietary inclusion should not exceed 20 g/kg. This would allow for near-maximal yolk VLC n-3 PUFA enrichment without impairing hen productive performance, altering the ovarian follicle hierarchy or, based on the work of others, presumably imparting off-flavors in the egg.

Supplementation of omega-3 fatty acids is considered a valuable strategy to supply the low intake of these fatty acids. Thus, the safety of the supplements is an important milestone. Because of that, we analyzed 20 unflavored supplements sold in the French market for fatty acid and triglyceride composition, for EPA and DHA, and for tocol content, as well as for oxidative status. This study found that only 2.5% of the supplements did not meet their label claims for omega-3 content. TAG analysis showed high variability among the triglyceride distribution, and the same trend was also noticed for the tocol content; in fact, a high variability of the distribution of the six tocols (four tocopherols and two tocotrienols) was found among the samples. Of the tested products, all of them complied with peroxide value, p-anisidine value, and Totox values established by the Global Organization for EPA and DHA Omega-3s (GOED) and were not oxidized. [ABSTRACT FROM AUTHOR]

Bitumen rejuvenators are used to improve or restore the physical and mechanical performance of aged bitumen. Traditional bitumen rejuvenators are a product of crude oil. As crude oil production declines and the environmental and financial costs of crude oil increase, there is an urgent need to identify more environmentally sustainable bitumen rejuvenator alternatives. Bitumen rejuvenators generated from biological sources offer an environmentally friendly and economically viable alternative to the crude oil-based bitumen rejuvenators. This paper describes a study wherein microalgae oil was used as an aged bitumen rejuvenator. The chemical, physical, and mechanical effects of microalgae oil on 70/100pen aged bitumen were investigated. The results indicate that microalgae oil has the potential to be used as an aged bitumen rejuvenator.

Three strategic edible oils, that is, olive oil, microalgae oil, and shea butter, with a significantly different composition of fatty acids (FA), have been studied in a static in vitro digestion model to evaluate the rate of hydrolysis, bioaccessibility, and micellar phases formed in the process. Lipid composition of each phase and how the lipids are distributed in the different phases have been obtained using this in vitro digestion model. We demonstrate that the composition in FA and the physical properties of the oil are the key factors determining the distribution of lipids in the different phases. The fastest rate of hydrolysis was observed for olive oil and the highest triacylglycerol conversion was attained for shea butter. In contrast, the most abundant precipitate phase was obtained for shea butter, which also produces the highest co‐crystallization of cholesterol among the three edible oils studied. This study reveals that digestibility of edible oils is directly related with the initial rate of hydrolysis. [ABSTRACT FROM AUTHOR]

Microalgae have a high capacity to capture CO2. Additionally, biomass contains lipids that can be used to produce biofuels, biolubricants, and other compounds of commercial interest. This study analyzed various scenarios for microalgae lipid production by simulation. These scenarios include cultivation in raceway ponds, primary harvest with three flocculants, secondary harvest with pressure filter (and drying if necessary), and three different technologies for the cell disruption step, which facilitates lipid extraction. The impact on energy consumption and production cost was analyzed. Both energy consumption and operating cost are higher in the scenarios that consider bead milling (8.79–8.88 kWh/kg and USD 41.06–41.41/kg), followed by those that consider high-pressure homogenization (HPH, 5.39–5.46 kWh/kg and USD 34.26–34.71/kg). For the scenarios that consider pressing, the energy consumption is 5.80–5.88 kWh/kg and the operating cost is USD 27.27–27.88/kg. The consumption of CO2 in scenarios that consider pressing have a greater capture (11.23 kg of CO2/kg of lipids). Meanwhile, scenarios that consider HPH are the lowest consumers of fresh water (5.3 m3 of water/kg of lipids). This study allowed us to develop a base of multiple comparative scenarios, evaluate different aspects involved in Chlorella vulgaris lipid production, and determine the impact of various technologies in the cell disruption stage. [ABSTRACT FROM AUTHOR]

Fish and algae are the major sources of n-3 polyunsaturated fatty acids (n-3 PUFAs). Globally, there is a rapid increase in demand for n-3 PUFA-rich oils. Conventional oil production processes use high temperature and chemicals, compromising the oil quality and the environment. Hence, alternative green technologies have been investigated for producing oils from aquatic sources. While most of the studies have focused on the oil extraction and enrichment of n-3 PUFAs, less effort has been directed toward green refining of oils from fish and algae. Enzymatic processing and ultrasound-assisted extraction with environment-friendly solvents are the most promising green technologies for extracting fish oil, whereas pressurized extractions are suitable for extracting microalgae oil. Lipase-catalysed ethanolysis of fish and algae oil is a promising green technology for enriching n-3 PUFAs. Green refining technologies such as phospholipase- and membrane-assisted degumming deserve investigation for application in fish and algal oils. In the current review, we critically examined the currently existing research on technologies applied at each of the steps involved in the production of oils rich in n-3 PUFAs from fish and algae species. Special attention was placed on assessment of green technologies in comparison with conventional processing methods. [ABSTRACT FROM AUTHOR]

Lipid nanocarriers smaller than 200 nm may be used as pharmaceutical/cosmetic raw materials as they are able to penetrate the skin. The nanostructured lipid carriers (NLCs) based on microalgae oil (Schizochytrium) and lipids extracted from diatoms (Halamphora cf. salinicola (strain SZCZM1454A)) were produced by the HSH (high shear homogenization) method. Fatty acid profile of crude oil from diatoms indicated the presence of palmitoleic, palmitic, stearic acid, oleic and myristic acids as the most common fatty acids in the strain investigated. The quantitative composition and the synthesis condition of NLC dispersions were optimized by using the full factorial designs. The physicochemical parameters of the obtained lipid nanocarriers were characterized by SEM, DSC and XRD measurements and the fraction with the optimum parameters (size below 200 nm, polydispersity index not exceeding 0.2 and zeta potential higher than +45 mV) was selected for further study. The positive charge of the obtained lipid nanoparticles is beneficial as permits electrostatic bonding with the negatively charged skin surface. As follows from stability tests, the NLCs obtained could be stored at room temperature. [ABSTRACT FROM AUTHOR]

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Recently, there is a growing interest in the use of microalga in various fields. Microalgae have properties such as rapid reproduction and high biomass accumulation, and under certain conditions, some are able to accumulate a large amount of oil. However, microalgae oil often contains more free fatty acids than the vegetable oil and is therefore unsuitable for biodiesel synthesis using alkaline catalysts. For this reason, some authors suggest the application of heterogeneous catalysis. A particular interest in the use of immobilized enzymes has developed. Other solid substances can also be used as heterogeneous catalysts are usually metal oxides, carbonates or zeolites. The use of these catalysts results in simpler biodiesel synthesis, especially purification processes, a cleaner end product and a less polluted environment. The molar ratio of alcohol to oil is lower during enzymatic transesterification, and more than 90% ester yield is obtained using a molar ratio of alcohol to oil of 3:1 to 4.5:1. The alcohols do not have a negative effect on the effectiveness of chemical catalysts, so it is possible to use alcohols in molar ratio from 4:1 to 12:1. The optimal temperature of enzymatic process is 30°C–50°C. An ester yield of more than 95% was obtained in 12–48 h. Using chemical catalysts, greater than a 95% yield of esters was obtained at higher temperatures in a shorter time. Material costs of enzymatic catalysis can be reduced by reusing the catalysts directly or after regeneration. [ABSTRACT FROM AUTHOR]

Commercial cultivation of eukaryotic microalgae has so far employed a unicellular form of species only (e.g., Chlorella pyrenoidosa, Dunaliella salina, and Haematococcus pluvialis). In this study, we assessed the feasibility of using the filamentous eukaryotic microalga Klebsormidium sp. LGX80 as a new cultivar for biomass and lipid production. The effects of different forms and concentrations of nitrogen on growth and lipid production of Klebsormidium sp. LGX80 were studied by using a glass column (ø4.5 × 60 cm) photobioreactor under laboratory conditions. Growth and lipid production of the new strain were further evaluated in an outdoor pilot‐scale tubular photobioreactor. The results showed that when supplied with urea as a source of nitrogen Klebsormidium sp. LGX80 yielded a final biomass concentration of 8.49 ± 0.10 g · L−1 in which a cellular lipid content was 59.2 ± 0.4% DW. Under such conditions, the biomass and lipid productivities were 471.7 ± 5.9 and 248.1 ± 0.0 mg · L−1 · d−1, respectively. Fatty acid analysis revealed that the main fatty acids of Klebsormidium sp. LGX80 were palmitic acid (C16:0), linoleic acid (C18:2ω6), and linolenic acid (C18:3ω3), of which linoleic acid (C18:2ω6) accounted for up to 67.5 ± 0.1% of total fatty acids. When grown outdoors in a 13,000‐L tubular photobioreactor with an initial nitrogen concentration of 3 mM urea, Klebsormidium sp. LGX80 reached the highest biomass concentration of 2.63 ± 0.09 g · L−1 with the cells containing 38.0 ± 0.5% lipids (% DW), resulting in the volumetric biomass and lipid productivities of 147.2 ± 3.6 and 37.9 ± 0.9 mg · L−1 d−1, respectively. The results of light:dark cycle experiment showed that a durative and prolonged light irradiation hindered the biosynthesis of chlorophyll a and chlorophyll b in the cells, but promoted the carotenoid accumulation. These results suggested that Klebsormidium sp. LGX80 can be a potential oleaginous filamentous microalga for commercial production of microalgal oils. [ABSTRACT FROM AUTHOR]

Commercial cultivation of eukaryotic microalgae has so far employed a unicellular form of species only (e.g., Chlorella pyrenoidosa, Dunaliella salina, and Haematococcus pluvialis). In this study, we assessed the feasibility of using the filamentous eukaryotic microalga Klebsormidium sp. LGX80 as a new cultivar for biomass and lipid production. The effects of different forms and concentrations of nitrogen on growth and lipid production of Klebsormidium sp. LGX80 were studied by using a glass column (ø4.5 × 60 cm) photobioreactor under laboratory conditions. Growth and lipid production of the new strain were further evaluated in an outdoor pilot‐scale tubular photobioreactor. The results showed that when supplied with urea as a source of nitrogen Klebsormidium sp. LGX80 yielded a final biomass concentration of 8.49 ± 0.10 g · L−1 in which a cellular lipid content was 59.2 ± 0.4% DW. Under such conditions, the biomass and lipid productivities were 471.7 ± 5.9 and 248.1 ± 0.0 mg · L−1 · d−1, respectively. Fatty acid analysis revealed that the main fatty acids of Klebsormidium sp. LGX80 were palmitic acid (C16:0), linoleic acid (C18:2ω6), and linolenic acid (C18:3ω3), of which linoleic acid (C18:2ω6) accounted for up to 67.5 ± 0.1% of total fatty acids. When grown outdoors in a 13,000‐L tubular photobioreactor with an initial nitrogen concentration of 3 mM urea, Klebsormidium sp. LGX80 reached the highest biomass concentration of 2.63 ± 0.09 g · L−1 with the cells containing 38.0 ± 0.5% lipids (% DW), resulting in the volumetric biomass and lipid productivities of 147.2 ± 3.6 and 37.9 ± 0.9 mg · L−1 d−1, respectively. The results of light:dark cycle experiment showed that a durative and prolonged light irradiation hindered the biosynthesis of chlorophyll a and chlorophyll b in the cells, but promoted the carotenoid accumulation. These results suggested that Klebsormidium sp. LGX80 can be a potential oleaginous filamentous microalga for commercial production of microalgal oils. [ABSTRACT FROM AUTHOR]

Supplementation of omega-3 fatty acids is considered a valuable strategy to supply the low intake of these fatty acids. Thus, the safety of the supplements is an important milestone. Because of that, we analyzed 20 unflavored supplements sold in the French market for fatty acid and triglyceride composition, for EPA and DHA, and for tocol content, as well as for oxidative status. This study found that only 2.5% of the supplements did not meet their label claims for omega-3 content. TAG analysis showed high variability among the triglyceride distribution, and the same trend was also noticed for the tocol content; in fact, a high variability of the distribution of the six tocols (four tocopherols and two tocotrienols) was found among the samples. Of the tested products, all of them complied with peroxide value, p-anisidine value, and Totox values established by the Global Organization for EPA and DHA Omega-3s (GOED) and were not oxidized.

[Display omitted] • The first study of microalgae oil on H 2 -rich gas by steam reforming. • Study of Ni/CeO 2 -ZrO 2 catalyst on steam reforming of microalgae oil. • Ni/CeO 2 -ZrO 2 showed high dispersion, small nickel crystals, and high surface area. • Optimum MAO steam reforming reaction conditions: 850 °C, 29 h−1, 12:1 steam:MAO. • Hydrogen selectivity: 99.82% under optimal conditions. This study investigated the steam reforming of microalgae oil in the existence of Ni/CeO 2 -ZrO 2 catalyst to assess its potential for hydrogen production. For this purpose, the catalyst was synthesized by the impregnation-co-precipitation method and characterized using various techniques. Catalytic microalgae steam reforming was performed in a continuous flow quartz fixed bed reactor and the effects of reaction temperature, weight hourly space velocity, and steam to microalgae volume ratio on conversion and hydrogen selectivity were evaluated. The findings revealed that microalgae oil, especially with a high oleic acid content, showed promise as a feedstock for hydrogen production via steam reforming. Suitable conditions were identified as a reaction temperature of 850 °C, weight hourly space velocity of 29 h−1, and steam to microalgae oil volume ratio of 12:1, resulting in 99.79 % hydrogen selectivity and 100 % microalgae oil conversion. Furthermore, a characterization of the spent catalyst was conducted, and a coke deposition of 19.17 mg carbon /g cat.h was observed following 15 h of reaction. [ABSTRACT FROM AUTHOR]

Microalgae have a high capacity to capture CO2. Additionally, biomass contains lipids that can be used to produce biofuels, biolubricants, and other compounds of commercial interest. This study analyzed various scenarios for microalgae lipid production by simulation. These scenarios include cultivation in raceway ponds, primary harvest with three flocculants, secondary harvest with pressure filter (and drying if necessary), and three different technologies for the cell disruption step, which facilitates lipid extraction. The impact on energy consumption and production cost was analyzed. Both energy consumption and operating cost are higher in the scenarios that consider bead milling (8.79–8.88 kWh/kg and USD 41.06–41.41/kg), followed by those that consider high-pressure homogenization (HPH, 5.39–5.46 kWh/kg and USD 34.26–34.71/kg). For the scenarios that consider pressing, the energy consumption is 5.80–5.88 kWh/kg and the operating cost is USD 27.27–27.88/kg. The consumption of CO2 in scenarios that consider pressing have a greater capture (11.23 kg of CO2/kg of lipids). Meanwhile, scenarios that consider HPH are the lowest consumers of fresh water (5.3 m3 of water/kg of lipids). This study allowed us to develop a base of multiple comparative scenarios, evaluate different aspects involved in Chlorella vulgaris lipid production, and determine the impact of various technologies in the cell disruption stage.

Lipid nanocarriers smaller than 200 nm may be used as pharmaceutical/cosmetic raw materials as they are able to penetrate the skin. The nanostructured lipid carriers (NLCs) based on microalgae oil (Schizochytrium) and lipids extracted from diatoms (Halamphora cf. salinicola (strain SZCZM1454A)) were produced by the HSH (high shear homogenization) method. Fatty acid profile of crude oil from diatoms indicated the presence of palmitoleic, palmitic, stearic acid, oleic and myristic acids as the most common fatty acids in the strain investigated. The quantitative composition and the synthesis condition of NLC dispersions were optimized by using the full factorial designs. The physicochemical parameters of the obtained lipid nanocarriers were characterized by SEM, DSC and XRD measurements and the fraction with the optimum parameters (size below 200 nm, polydispersity index not exceeding 0.2 and zeta potential higher than +45 mV) was selected for further study. The positive charge of the obtained lipid nanoparticles is beneficial as permits electrostatic bonding with the negatively charged skin surface. As follows from stability tests, the NLCs obtained could be stored at room temperature.

In this study, it is demonstrated that natural microalgae oils, which contain fatty acid components including docosahexaenoic acid (DHA), could be directly applied to fabricate vesicular structures in aqueous phase through a forced formation process. The microalgae oil vesicles had initial average diameters of 170- 230 nm with negative charges apparently caused by dissociation of the fatty acid components. The vesicles possessed excellent stability with lifetimes for at least 450 days. The formation of the vesicular structures with hydrophilic cores/regions was confirmed by the transmission electron microscopy (TEM) image and successful encapsulation of a hydrophilic material. For encapsulation of a hydrophobic material, lutein, the vesicle size was increased probably due to the insertion of lutein into the hydrophobic vesicular bilayer structures. The analysis of Fourier transform infrared (FTIR) spectroscopy suggested that the vesicular bilayer fluidity was decreased by encapsulating lutein. However, the lutein-encapsulating microalgae oil vesicles still possessed high stability and the vesicular structures could maintain intact even at an environmental temperature up to 60℃. Applicability of the microalgae oil vesicles as drug delivery carriers was also demonstrated by successful encapsulation of curcumin. However, when the loaded curcumin was increased to a certain amount, physical stability of the microalgae oil vesicles was significantly reduced. This is probably because the vesicular structures with only limited spaces for accommodating hydrophobic materials were strongly affected by encapsulating a large amount of curcumin. It is interesting to note that by adding egg L-α-phosphatidylcholine, the curcumin encapsulation-induced instability of the microalgae oil vesicles could be alleviated. The results indicated that vesicular structures could be fabricated from microalgae oils and the microalgae oil vesicles were capable of encapsulating hydrophilic or hydrophobic materials for drug delivery applications. The findings lay a background for further dosage form development of nutritional supplements encapsulated by natural microalgae oils.

Microalgae are a valuable and rich source of oil. By the means of using microalgae oil as raw materials or additives for edible oil will improve the nutritional and edible value of the latter. This paper compares the lipid content and fatty acid composition of microalgae and traditional oil crops, elaborates the lipid synthesis mechanism of microalgae cells and the strategies of promoting lipid accumulation both from environmental pressure and from molecular pressure, summarizes the methods of breaking microalgae cell walls and extracting oil, analyzes the nutritional value, toxicity, antioxidant, and economic feasibility issues to be considered in microalgae edible oil. It is hoped that this study could provide theoretical basis for the actual production of microalgae edible oil, and provide inspiration for the research on the synthesis, accumulation, extraction and preparation of microalgae oils.

Oils rich in omega-3 have been of industrial and economic importance, mainly for its benefits in human and animal health. Fish is considered the primary source for obtaining omega-3. The resurgence of interest in the use of omega-3 as a functional food has led to the need of alternative sources in this growing market. Omega-3 produced by marine thraustochytrids have appeared as an alternative to fish oil and an eco-friendly solution to overfishing. Here, we review key mechanisms that enable sustainable production and technological prospection of omega-3 from thraustochytrids. Sustainability analysis identified strengths, weaknesses, opportunities and threats for omega-3 oils from thraustochytrids. Thus, this study shows the technological prospection based on the worldwide patent landscape. Thraustochytrids have also been known as microalgae on the international market, which has been well received by consumers as a natural or vegan source of omega-3 supplementation. Thus, omega-3 oils can be developed in controlled bioprocess systems preventing the production of toxins and pollutants. Hence, the technological prospection showed a growing trend with 731 patents published between 1999 and 2018. Most patents were classified within the chemical and human areas, which highlighted omega-3 oils involving biosynthesis by microorganisms such as Aurantiochytrium in food applications. These technologies have been mainly developed by countries, such as the United States, China, Netherlands and Japan, which refer to bioreactor cultivation, strains improvement and food formulations. Thus, global patent search allowed to analyze technological advances, trends and market gaps of omega-3 oils from thraustochytrids as a renewable technological solution. • Thraustochytrids are a vegetarian, renewable and sustainable source of omega-3 oils. • Thraustochytrids are a potential novel source of omega-3 to supplement fish oils. • Omega-3 oils from thraustochytrids has higher yields than fish oil. • Thraustochytrids oils are produced in a controlled and optimized bioprocess system. • United states and Eurasia lead omega-3 rich oils market from thraustochytrids. [ABSTRACT FROM AUTHOR]

Most of the population is dependent on supplemental products to reach the recommended level of omega-3 polyunsaturated fatty acid (ω-3 PUFA) intake. Thus, knowledge about the quality of ω-3 supplements is important for their safe consumption. In this work, attenuated total reflectance–Fourier transform infrared (ATR-FTIR) and nuclear magnetic resonance (NMR) spectroscopy were applied to assess the quality of fourteen commercial ω-3 supplements. Using ATR-FTIR data, we could identify whether ω-3 PUFA was esterified as either triacylglyceride (71%) or ethyl (29%) esters in ω-3 supplements. The type of esterification is rarely included in the product labels, although the consumer should have the right to choose which form of the supplement to consume. On the other hand, 1H NMR spectra were useful to determine the relative concentration of eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids, and ω-3 PUFA in these commercial samples. Ethyl esters have higher concentrations of unsaturated fatty acids. The NMR results showed a good agreement between the obtained and declared DHA and EPA amounts on the product labels, except for one sample whose high level of ω-3 PUFA indicated it to be a vegetable oil-enriched supplement. Moreover, ω-3 supplements from Schizochytrium sp. microalgae oil revealed higher levels of DHA and ω-3 PUFA, but lower levels of EPA than fish oil. These findings indicate the need for a constant assessment of the quality of commercial products whose ATR-FTIR spectra could be routinely used for the evaluation of PUFA esterification, and NMR analysis could be used to provide advanced quantitative information on commercial ω-3 supplements. [ABSTRACT FROM AUTHOR]

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Although the methanolysis of microalgae oil for biodiesel preparation was studied previously, the ethanolysis for the combined production of fatty acid ethyl esters (FAEEs, also can be used as biodiesel) and the ethyl esters of PUFAs (an important health-care product) rarely reported. In this work, a novel two-step process, hydrolysis of microalgae oil followed by lipase-mediated ethanolysis, was developed for the synthesis of FAEEs and the ethyl ester of PUFAs. The hydrolysis was firstly performed and the generated free fatty acids was collected and further used for FAEEs synthesis catalyzed by lipase. For lipase-catalyzed ethanolysis, the adding strategy of methanol, molecular sieve dosage, lipase dosage and temperature had significant influence on the FAEE yield. Under the optimized conditions, a FAEE yield of 97% could be obtained. Novozym435 was found to be equally effective for catalyzing the ethanolysis of conventional free fatty acids and PUFAs. The combined effects of multiple factors on the ethanolysis was further studied using Response Surface Methodology (RSM). Validation statistical analysis suggested that the negative correlation existed between FAEE yield and the water content. This work provided a novel strategy to produce FAEEs and the ethyl esters of PUFA effectively with microalgae oil as the substrate. • A novel two-step process was developed for the synthesis of biodiesel and the ethyl ester of PUFAs. • A final FAEE yield of 97% could be obtained. • The combined effects of multiple factors on the ethanolysis was investigated using Response Surface Methodology (RSM). [ABSTRACT FROM AUTHOR]

Currently, the renewable feedstock is the most needed worldwide. Microalgae are promising raw materials for supplying biofuels due to the depletion of fossil fuels. The microalgae found were mostly consists of freshwater algae. The aim of this research is to study the effect of different solvents and ratio using Soxhlet extraction method. Many parameters were introduced in this study in order to enhance the lipid production of microalgae. Lipid content of algae oil production known as Fatty acid that found was being analyzed. Different solvents used and ratio was expected to have different highest in lipid content. Chloroform, ethanol, and hexane were chosen as the solvents used. The best solvent for lipid production was the combination of different solvents and ratio. Data showed that 8% is the highest total oil extraction yield obtained from combination of chloroform and ethanol with a ratio (1:2). The compound and lipid content in algae oil are analyzed through Gas Chromatography Mass Spectrometer (GC-MS) analysis. Fatty acids have many benefits and also have interest preparation for health products. Green microalgae strain was being identified and cultured as future potential for biodiesel production. Significant of this study is to unveil the benefit of algae oil as sustainable future resources. [ABSTRACT FROM AUTHOR]

Microalgae can produce valuable metabolites such as protein, fatty acids, carbohydrates, minerals, pigments, vitamins, sterols, antioxidants and bioactive polyphenols, which are rich sources of active ingredients. Thanks to these valuable metabolites, microalgae today have the potential to be used in many areas such as food, cosmetics, pharmaceuticals and agriculture. Green single cell Chlorella sp. belonging to the Chlorophyta group shows antitumor, anticoagulant, antibacterial, antiviral, antifungal and antioxidant activity. It is known that microalgae oils have antimicrobial effect against fungal microorganisms and can be used as a preservative in foods. In this study, the antifungal activity of Chlorella protothecoides microalgae oil, an alternative to chemical preservation, against Penicillium chrysogenum and Aspergillus parasiticus fungi, which may cause qualitative and quantitative losses in foods, was determined. The antifungal effect of C. protothecoides microalgae oil prepared by using 5% and 10% concentrations in dimethyl sulfoxide (DMSO) against these fungi was determined by the disc diffusion method. In both fungal pathogens, C. protothecoides microalgae oil decreased micellar growth. The antioxidant activity of the C. protothecoides microalgae oil was determined using the 1,1-diphenyl-2-picryl hydrazyl (DPPH) free radical removal method. Antioxidant effect of microalgae oil was determined as 45.93%. C. protothecoides microalgae oil had an antifungal activity against P. chrysogenum and A. parasiticus. According to the results, it can be concluded that C. protothecoides oil may be used as a food preservative in the food industry. [ABSTRACT FROM AUTHOR]

Abstract Changing solvent polarity at subcritical conditions, by an appropriate co-solvent, may be used to enhance oil extraction from different raw materials. As a newly commercially interested process, oil extraction from Nannochloropsis salina as a valuable bio-resource, by subcritical water-ethanol mixture as a polarity altered solvent, was investigated. Response surface methodology (RSM) was applied to achieve the best operating conditions. Three factors including temperature (90–150 °C), water-ethanol concentration (25–75 wt%) and flow rate (1.0–4.0 ml/min) were investigated. The best separation conditions were determined at 90 °C, 75 wt% ethanol and 4 ml/min. The oil composition was compared with four other methods including subcritical water extraction (SCWE), ultrasound-assisted extraction (UAE), Soxhlet (SOX) and Folch methods. The main fatty acids were identified as C16:0, C18:0, C18:1c and C18:3c. The highest extraction efficiency of 33.93 wt% was achieved for subcritical water/ethanol mixture. Highlights • SSE of oil from N. salina by water-ethanol mixture was studied. • The best operating conditions were obtained using RSM. • Ethanol co-solvent improved solvent polarity and enhanced extraction yield. • Optimal SSE yield was significantly higher than the other conventional techniques. [ABSTRACT FROM AUTHOR]

Abstract In this study, subcritical water extraction (SCWE) was used for dynamic extraction of crude oil of Nannochloropsis salina. The effect of three parameters including water temperature, flow rate and sample loading on the extraction efficiency was investigated and the whole process was simulated by using a two-phase mathematical model. Water temperature, flow rate and sample loading were varied from 150 to 200 °C, from 1 to 4 mL/min and from 1 to 4 g, respectively. The best operating conditions were selected to be 175 °C, 4 mL/min and 1 g and at those conditions, the fatty acids profile was compared with the Folch method. Because of the nature of the biomass and small particle sizes of the cells, a mathematical model based on the shrinking core model (SCM) was developed to evaluate the behavior of the extraction process. Kinetic parameters of the model incl. external film mass transfer coefficient (k f), solute-solvent binary diffusion coefficient (D 12), axial dispersion coefficient (D ax) and effective diffusivity (D e) in solid particle were determined. The later one was selected as the tuning parameter of the model and the others were attained from available correlations. The model predictions were in good agreement with experimental data. Graphical abstract Image Highlights • Extraction of Nannochloropsis salina oil using subcritical water was investigated. • Optimum operating conditions was obtained. • Modeling SCWE was carried out by the shrinking core model applying effective diffusivity in solid phase as tuning parameter. • Modeling and simulation of the process was carried out successfully. [ABSTRACT FROM AUTHOR]

In this work, activities of modified dolomite catalysts using calcium acetate in the heterogeneously catalyzed transesterification of microalgae oil with methanol were investigated. Modified catalysts were prepared via wet impregnation method and calcined 850 °C for 2 h. Reaction conditions were examined as the catalyst type, amount of catalyst, methanol/microalgae oil molar ratio, and reusability of the catalyst using the dolomite and modified dolomite catalysts. When investigated reusability of the modified dolomite catalyst in the transesterification of microalgae oil with methanol, catalyst was reused three times with a small loss of activity. After fourth run, reused catalyst was calcined again and got similar activity to the first run. The highest fatty acid methyl esters (FAME) yield of 90% was obtained when the reaction was performed with methanol/microalgae oil molar ratio of 6:1, catalyst amount of 3%, and reaction temperature at 65 °C for 3 h by using the 30% CaO/dolomite catalyst. [ABSTRACT FROM AUTHOR]

Abstract Increasing global energy demand at a rate faster than the population growth has led the researcher to look for alternative fuel. Amongst the options, biodiesel is an environmentally sustainable substitute of diesel fuel being renewable, biodegradable and have similar properties of fossil diesel. Among the biodiesel sources, microalgae is a potential third generation biodiesel feedstock which can be produced throughout the year and its oil yield is higher than any other crops. This paper reviews recent development in microalgae biodiesel in terms of its oil extraction technics, challenges of oil extraction, production of biodiesel from microalgae oil and its fuel properties. Finally, the paper discusses the performance and combustion analysis of diesel engine fuelled with microalgae biodiesel. This paper provides a clear understanding of the potential use of microalgae biodiesel as an alternative source to fossil diesel for diesel engines. [ABSTRACT FROM AUTHOR]

Highlights • Lipase A from P. aeruginosa was displayed on P. pastoris cells. • Biochemical characterization and stability of the LipA was investigated. • Esterification was used to biodiesel production from algae oil by the biocatalyst. • Operational stability of enzyme was tested in 10 repeated batch cycles. Abstract Yeast surface display has become a powerful technology in recent decades and one of the promising areas in this field is the biodiesel synthesis by microbial lipases. Hence, in this study the optimized lipase A (Lip A) gene from Pseudomonas aeruginosa was fused to GPI-anchored protein Gcw61 and successfully displayed on the surface of Pichia pastoris X33. A lipase activity of 85.2 U/mg dry cell weight was obtained from recombinant P. pastoris. The copy numbers of inserted lipase gene were determined 2.09 ± 0.06 by real time PCR absolute quantification method. The enzyme showed the best stability in pH 7.0–10.0 and at temperature 37 °C–40 °C and was also stable in hydrophilic organic solvents. Ca2+, Mg2+, Mn2+ and Cu2+ ions enhanced enzyme activity, whereas Fe2+ and Zn2+ ions and some detergents like SDS, CTAB, Tween 20 and 80 dramatically decreased the activity of the enzyme. The results demonstrate that our whole cell biocatalyst exhibited a good potential for biodiesel production from microalgae oil in 10 repeated batch cycles. [ABSTRACT FROM AUTHOR]

Microalgae oil can be converted into aviation fuel to reduce dependence on fossil fuels and decrease the carbon footprint. This could be a significant step toward sustainable energy resources that have the potential to produce 'drop‐in' fuels. Algae‐based fuels are potential substitutes for fossil fuels due to the quality of their crude oil. However, this is only possible if appropriate conversion processes are undertaken. Conversely, microalgae species have low lipid content and biomass harvesting is still an energy‐demanding process. In this study, a conceptual design is developed for the conversion of microalgae oil to jet fuel. It is based on a process undertaken in the laboratory using a species named Nannochloropsis sp. Nutrients and CO2 were supplied to the growing culture for effective growth. Biomass harvesting was completed on the tenth day of the growth cycle. It was followed by physiological modification to improve lipid content. Finally, crude oil extraction was followed by bio‐oil hydrocracking at 350 °C, and fractionation of cracked bio‐oil between 70 and 300 °C to separate light‐, middle‐, and heavy‐end hydrocarbons for use in the production of jet fuel. During simulation, reforming and upgrading processes were added to the design to enhance the quality of the jet fuel to be produced on large scale in the future. The study, including the results, suggests that it is technically feasible to convert microalgae oil into jet fuel because of the similarity between algae bio‐oil and petroleum crude oil. © 2018 Society of Chemical Industry and John Wiley & Sons, Ltd [ABSTRACT FROM AUTHOR]

Using renewable oxygenated fuels such as ethanol is a proposed method to reduce diesel engine emission. Ethanol has lower density, viscosity, cetane number and calorific value than petroleum diesel (PD). Microalgae oil is renewable, environmentally friendly and has the potential to replace PD. In this paper, microalgae oil (10%) and ethanol (10%) have been mixed and added to (80%) diesel fuel as a renewable source of oxygenated fuel. The mixture of microalgae oil, ethanol and petroleum diesel (MOE20%) has been found to be homogenous and stable without using surfactant. The presence of microalgae oil improved the ethanol fuel demerits such as low density and viscosity. The transesterification process was not required for oil viscosity reduction due to the presence of ethanol. The MOE20% fuel has been tested in a variable compression ratio diesel engine at different speed. The engine test results with MOE20% showed a very comparable engine performance of in-cylinder pressure, brake power, torque and brake specific fuel consumption (BSFC) to that of PD. The NOx emission and HC have been improved while CO and CO2 were found to be lower than those from PD at low engine speed.

Microalgae oil is expected to be a relevant source of biofuel in the future as it is more favorable to confront the problems of food shortages and greenhouse emission challenges raised by conventional biofuels. Therefore, in this study, a most common kind of microalgae that have a great potential, Chlorella protothecoides, was evaluated as fuel in terms of its combustion and emission characteristics in a Diesel engine-powered generator set at constant engine speed of 1500 rpm under various loads after converting its oil to biodiesel by typical base-catalyzed trans- esterification process. A biodiesel/diesel blend at the rate of 20% by volume was tested too. According to results obtained, using biodiesel resulted in an increase in fuel consumption, in a slight reduction of efficiency, and in sharp reductions in both unburned hydrocarbon emissions and smoke opacity especially at light loads, despite increasing NOx emissions were observed when compared with conventional petroleum diesel. In addition, premixed combustion ratio was higher for biodiesel than for diesel while total combustion duration took shorter for biodiesel especially at higher loads. The overall results of the study reveals that the combustion parameters of the biodiesel studied here are within the typical ranges of conventional biodiesel fuels. [ABSTRACT FROM AUTHOR]

The aim of this study is to produce new medium-long-medium structured triacylglycerols (MLM-STAGs) containing caprylic acid (CA) at the sn -1,3 positions, and long chain saturated fatty acids (LCSFAs) and bioactive fatty acids at the sn -2 position via two-step enzymatic process by Lipozyme TL-IM, using autotrophic microalgae ( Isochrysis galbana ) TAGs. In the first step, the ethanolysis of microalgae oil TAGs for 2-monoacylglycerols (2-MAGs) production are performed in the presence of water content of 5 wt% at ethanol/oil mole ratio of 24:1 with Lipozyme TL-IM at 25 °C for 12 h. In the larger-scale production of 2-MAGs, the 2-MAGs yield and the purity of the purified MAGs attained are 31.44-36.08 wt% and 91.57 mol%, respectively. In the second reaction, these 2-MAGs are esterified with caprylic acid (CA) in n -hexane system to synthesize almost pure MLM-STAGs with the recycled Lipozyme TL-IM under the optimized conditions. The final MLM-STAGs contain 64.28% CA and 13.35% ω-3 polyunsaturated fatty acids. The CA-LCSFAs-CA (43.01%) and novel CA-stearidonic acid (SDA, C 18:4ω-3 )-CA (23.88%) are the major MLM-STAGs present. In all, Isochrysis galbana -derived oil containing SDA is a promising source for producing high-value microalgal bioproducts by two-step enzymatic process in a cost-effective manner. [ABSTRACT FROM AUTHOR]