Lipid Extraction Yield Research Articles

Comparative assessment of pretreatment strategies for production of microalgae-based biodiesel from locally isolated Chlorella homosphaera

The yield and quality of lipids extracted from microalgal biomass are critical factors in the production of microalgae-based biodiesel. The green microalga Chlorella homosphaera, isolated from Beira Lake, Colombo, Sri Lanka was employed in the present study to identify the effect of chlorophyll removal and cell disruption methods on lipid extraction yield, fatty acid methyl ester (FAME) profile and quality parameters of biodiesel; including cetane number (CN), iodine value (IV), degree of unsaturation (DU) and high heating value (HHV). In the first section of this study, chlorophyll was removed from dry microalgae biomass prior to lipid extraction. Through the analysis of FAME profiles, it was observed that chlorophyll removal yielded biodiesel of enhanced quality, albeit with a lipid loss of 44.2% relative to the control. In the second section of the study, mechanical cell disruption strategies including grinding, autoclaving, water bath heating and microwaving were employed to identify the most effective method to improve lipid recovery from chlorophyll-removed microalgae biomass. Autoclaving (121 °C, 20min sterilization time, total time 2h) was the most effective cell disruption technique of the methods tested, in terms of lipid extraction yield (39.80%) and also biodiesel quality. Moreover, it was observed that employing cell disruption subsequent to chlorophyll removal has a significant impact on the FAME profile of microalgae-based biodiesel, and consequently served to increase HHV and CN although IV and DU did not vary significantly.

Use of ultrasound for aiding lipid extraction and biodiesel production of microalgae harvested by chitosan

ABSTRACT In this work, chitosan, a biodegradable flocculant, was investigated to determine its utility in flocculating microalgae, its effect on cell integrity, and its impact on lipid extraction and the conversion to fatty acid methyl ester (FAME). Results showed that chitosan adequately performed flocculation on Chlorella vulgaris microalgae and achieved a high harvesting efficiency of 96.35 ± 1.96% when implemented under the following conditions: chitosan dose = 120 mg/L−1, pH = 5, mixing speed = 150 rpm for 20 min, followed by 10 min of settling time. Moreover, scanning electron microscope (SEM) combined with transmission electron microscope (TEM) demonstrated that chitosan protected the cells’ structure from morphological damage. Finally, the highest lipid extraction yield and biodiesel production was obtained from the chitosan-harvested biomass when the microalgae were pretreated with ultrasound.

Mono-alkyl esters (biodiesel) production from wastewater sludge by esterification

To realize higher yields of mono-alkyl esters (Biodiesel) without sacrificing the environment and food sources; various researchers have considered utilizing different waste materials. In this work lipid extraction and their conversion into esters from wastewater sludge was investigated using a mixture of polar and non-polar solvents, methanol and homogeneous sulfuric acid catalyst. The effect of solvent extraction time, concentration of acidic catalyst used and the esterification reaction time to produce esters is reported for ex-situ two step and in-situ one step method. The whole experimental work of ex-situ/in-situ extraction and esterification was performed at a temperature of 100 °C and mixing rate of 100 rpm. Solvent extraction yield of lipids increased from 34 to 53% in two to six hours of solvent extraction. It was found that acidic catalyst concentration in the esterification mixture and esterification reaction time both have a major impact on esters yield. A highest ester yield of 78% was noted in the ex-situ two step method with two hours of esterification of filtered lipids and a 55% ester yield was noted in the in-situ one step method after six hours of simultaneous extraction and esterification in the same reactor respectively.

Comparison of Conventional and Sustainable Lipid Extraction Methods for the Production of Oil and Protein Isolate from Edible Insect Meal.

Edible insects represent an interesting alternative source of protein for human consumption but the main hurdle facing the edible insect sector is low consumer acceptance. However, increased acceptance is anticipated when insects are incorporated as a processed ingredient, such as protein-rich powder, rather than presented whole. To produce edible insect fractions with high protein content, a defatting step is necessary. This study investigated the effects of six defatting methods (conventional solvents, three-phase partitioning, and supercritical CO2) on lipid extraction yield, fatty profiles, and protein extraction and purification of house cricket (Acheta domesticus) and mealworm (Tenebrio molitor) meals. Ethanol increased the lipid extraction yield (22.7%–28.8%), irrespective of the insect meal used or the extraction method applied. Supercritical CO2 gave similar lipid extraction yields as conventional methods for Tenebrio molitor (T. molitor) (22.1%) but was less efficient for Acheta domesticus (A. domesticus) (11.9%). The protein extraction yield ranged from 12.4% to 38.9% for A. domesticus, and from 11.9% to 39.3% for T. molitor, whereas purification rates ranged from 58.3% to 78.5% for A. domesticus and from 48.7% to 75.4% for T. molitor.

Solvent screening and process optimization for high shear-assisted lipid extraction from wet cake of Nannochloropsis sp.

Microalgae are regarded as a promising feedstock for biofuels and value-added products but still suffer from an inefficient lipid extraction process. In the present study, a simple and energy-efficient extraction method is demonstrated to extract oil directly from the wet cake (260 g/L) of Nannochloropsis sp. with an assist from the high shear mixer (HSM). After the initial solvent screening, the composition of co-solvent and operating conditions were optimized according to lipid composition and extraction yield. The high shear-assisted extraction process was found to achieve 83% lipid extraction yield (94% for EPA) in 5 min and 95% yield (100% for EPA) in 30 min with minimal amounts of solvents (0.9 ml hexane, 0.39 ml ethanol, and 0.057 ml sulfuric acid for 1 g of wet cell) at 8000 rpm, 55 °C. In comparison with various two-step wet extraction methods, the HSM offers the most economical extraction in terms of specific energy consumption of 1.38 MJ/kg dry cell. Therefore, the HSM can be considered as an attractive alternative to conventional extraction methods, providing a new paradigm of wet extraction for microalgae.

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

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.

Biodiesel production from Halamphora coffeaeformis microalga oil by supercritical ethanol transesterification

The marine benthic diatom Halamphora coffeaeformis is a potential feedstock for biodiesel production. This species shows high growth rates, important triacylglycerol (TAG) contents and grows in seawater making large-scale cultivation advantageous. Moreover, sustainable biofuel production in future biorefineries requires the implementation of technologies that employ renewable solvents. Thus, the goal of this work was to evaluate ethanol usage as extraction solvent and reaction medium for biodiesel production from H. coffeaeformis. In a first step a bio-oil extraction was carried out comparing ethanol and n-hexane to investigate the performance of ethanol with respect to a conventional solvent. Then, a free-catalyst supercritical ethanol transesterification of the bio-oils was carried out to obtain biodiesel. Higher lipid extraction yields were obtained using ethanol respect to n-hexane (26 wt.% vs 21.1 wt.%). The transesterification of crude lipids extracted with ethanol as solvent at 305 °C and 40 min. produced up to 15.9 wt.% of biodiesel respect to dried biomass processed. Comparable biodiesel yields were obtained using non-renewable organic solvents and a conventional catalytic technology. Thus, ethanol extraction and subsequent supercritical transesterification of H. coffeaeformis oil proved to be technically feasible and environmental friendly technology for the production of biodiesel.

Hydrothermal liquefaction of residual microalgae biomass after pulsed electric field-assisted valuables extraction

Efficient extraction of valuable products from microalgae and utilization of the residual biomass for biofuel production appear to bring economic benefits for the microalgae biorefineries. The pulsed electric field (PEF) method has been proposed as a promising pre-treatment for microalgae wet extraction. For conversion of microalgae biomass and residues, hydrothermal liquefaction (HTL) is considered a suitable method. Here, a combination of PEF-assisted valuables extraction of microalgae and HTL of the residual biomass is studied for the first time. The microalgae Auxenochlorella protothecoides, Chlorella vulgaris, and Scenedesmus almeriensis were cultivated, harvested, treated by PEF, and then subjected to lipid extraction, protein extraction, or extraction of amino acids after enzymatic protein hydrolysis. The residual biomass obtained from PEF-assisted valuables extraction was subjected to HTL in micro autoclaves at a temperature of 350 °C and pressure of 25 MPa for 15 min holding time. Product yields and analytical results obtained by elemental content measurement, 1H-nuclear magnetic resonance spectroscopy, Fourier-transform infrared spectroscopy, and gel permeation chromatography show that PEF alone has no significant direct influence on microalgae HTL. The harsh HTL conditions decisively determine the product yields and biocrude quality. However, PEF enhances the lipid extraction yield from 4 wt% to 33 wt%. Consequently, the biocrude yield decreases from 58 wt% to 43.2 wt%. Moreover, PEF boosts the protein extraction yield from almost zero to 41.6 wt% of the total protein, resulting in an increased biocrude yield by about 2 wt%. Finally, PEF accelerates the formation of amino acids by enzymatic hydrolysis, improving the extraction efficiency up to 150% in the first 60 min of the extraction. The extracted residue promises to produce a biocrude yield higher by 6 wt% and a better biocrude quality with lower nitrogen content. An overall mass balance of PEF-assisted valuables extraction and HTL is presented.

A facile and mild one-pot process for direct extraction of lipids from wet energy insects of black soldier fly larvae

The insect lipids were recovered using one-pot manner via a high speed homogeniser from the wet black soldier fly larvae as the novelty lipid feedstocks at room temperature and pressure in this study. The comparison of the influences of different conditions (solvent types, solute-solvent ratios, water contents, and homogenization intensities) on the lipid extraction efficiency and lipid compositions were studied and evaluated. The results indicated that all the binary solvents tested in this work present a higher extraction capacity (70–74%) than the monophasic solvent increasing two-fold the lipid extraction yield. There was a significant difference between the 30.96% and 86.67% in saponifiable lipids purity for different extraction solvent systems. The effects of water contents on the lipid extraction process for relatively low contents of non-polar solvent in the binary extraction solvents system were greater than that of high contents of non-polar solvent. However, fatty acid methyl esters profiles from the energy biomass indicate that relevant fatty acids were present in all solvent extracts, with no significant variation in the FAME composition provided for different investigated conditions. Key characteristics of the recovered lipids indicate that the pretreatment process-cell disruption was a critical step in the recovery of intracellular lipids from the wet biomass, which significantly enhancing the lipid extraction process. In combination with SEM images of the damaged cells, the precise mechanism of cell disruption via the high speed homogeniser was comprehensively described. At last, the kinetic model (r2 ≥ 0.9937) of lipid extraction from the ruptured cell at various homogenization intensities (6000–14000 rpm) was explored in preliminary. The extraction constants were determined for the lipid extraction process, ranging from 0.0531 to 0.0681 s−1. Considering its energy-efficiency and potential for scale-up, the one-pot manner may be a promising method to achieve industrial-scale lipid extraction from wet biomass.

Impact of pulsed electric field pretreatment on yield and quality of lipid extracted from cephalothorax of Pacific white shrimp (Litopenaeus vannamei) by ultrasound‐assisted process

SummaryPacific white shrimp cephalothorax was subjected to pulsed electric field (PEF) pretreatment at different electric field strengths (4, 8, 12 and 16 kV cm−1) and pulse numbers (120, 160, 200 and 240) to enhance the extraction yield of lipids. PEF‐treated samples were subsequently subjected to lipid extraction using ultrasound‐assisted extraction (UAE) process at ultrasound amplitude of 80% for 25 min in continuous mode. PEF‐pretreated samples subjected to UAE rendered the highest lipid yield (30.34 g 100 g−1 solids). PEF pretreatment resulted in reduced lipid oxidation as evidenced by the decreases in peroxide value (PV) and thiobarbituric acid reactive substances (TBARS). Lipids from PEF‐pretreated samples extracted using UAE had higher content of PUFAs and carotenoids, including astaxanthin, astaxanthin monoester, astaxanthin diester, canthaxanthin and β‐carotene. Overall, PEF pretreatment helped in enhancing the extraction yield of lipids and carotenoids from shrimp cephalothorax and reduce lipid oxidation to some extent.

Use of organic acids to improve fractionation of the black soldier fly larvae juice into lipid- and protein-enriched fractions

This study focusses on the fractionation of proteins and lipids from insect biomass, more specifically from black soldier fly larvae. Insects are rich in proteins and lipids and offer potential as a protein source for food and feed. Fractionation processes often focus on extracting only one compound (lipid or protein), neglecting the impact of the extraction method on other compounds. The current study aimed at the development of a robust fractionation process for wet insect biomass, targeting enriched protein fractions with higher valuable techno-functional properties as well as enriched lipid fractions. The use of different organic acids was evaluated and compared with an inorganic acid (HCl). A beneficial effect of organic acids on the lipid extraction yield (shift from 35 to 45%) was observed, that did not negatively influence the protein extraction efficiency. One organic acid, in particular, lactic acid, increased the lipid purity from 75 to 85%. Protein fractions with a purity of 60% proteins were achieved and were shown to preserve partial solubility. Use of some organic acids at low pH (pH 2) resulted in (1) a higher lipid purity in the lipid-enriched fraction and (2) had similar results in protein fractionation as the inorganic acid. Reproducibility of the fractionation process was proven.

High shear-assisted solvent extraction of lipid from wet biomass of Aurantiochytrium sp. KRS101

The importance of microalgae as a potential source of biofuel and value-added products has led to the development of microalgae-based biorefinery in recent years. However, the downstream process including lipid extraction and the refining process remains one of the main problems for commercialization due to its low economic feasibility induced by high usage of organic solvents and energy consumption. To solve these problems, a high shear mixer (HSM) was applied to the downstream process in this study. We first demonstrated both lipid extraction and degumming process using a bench-scale HSM with concentrated wet biomass (360 g/L) of DHA-rich oleaginous Aurantiochytrium sp. The high shear-assisted lipid extraction process was developed based on key operating parameters, the solvent to wet cell (S/W) ratio, rotational speed (rpm), and temperature. Our results revealed that 90% lipid extraction yield was achieved with the lowest energy consumption (4.83 MJ/kg) and solvent usage (5.9 ml/g dry cell) at conditions of a 2:1 (w/v) of S/W ratio and 7000 rpm at 55 °C for 30 min treatment. In the degumming process, the impurities were removed from the crude oil by hydrating phospholipids. As a result, highly purified degummed oil with the negligible phosphorus content (5 ppm) was obtained. These results suggest that the HSM can be applied to the downstream process to obtain highly purified lipids with low energy consumption and solvent usage, thereby dramatically improving the overall economic feasibility compared to the conventional process.

Evaluation, comparison of different solvent extraction, cell disruption methods and hydrothermal liquefaction of Oedogonium macroalgae for biofuel production

Cell disruption and lipid extraction methods for macroalgae are not well reported. Therefore, we compared various lipid extraction methods and extraction efficiency of various solvents to improve lipid yields from Oedogonium fresh water macroalgae. Lipid extraction was done by 2 methods viz., modified Bligh and Dyer method and soxhlet extraction using either single solvents or mixtures. In soxhlet extraction method five solvents were used (1) Hexane commonly used solvent for lipid extractions, (2) chloroform: methanol (2:1), (3) Chloroform: hexane (1:1), (4) Chloroform: hexane (1:2), (5) Dichloromethane + methanol (2:1). To improve lipid extraction yields, various cell disruption methods were also compared during the present study. Impurities of chlorophyll and protein were also detected in the extracted lipids. Hydrothermal liquefaction of algal biomass with TiO2 was also conducted at 300 °C. HTL was more effective by which 23.3 wt% of bio-crude oil was obtained.

Chlorella vulgaris cell disruption using copper sulfate

This study evaluated the feasibility of using copper sulfate as an agent for Chlorella vulgaris cell disruption. About 70% of the cells in a C. vulgaris suspension at ∼0.2 g/L concentration were disrupted at a copper sulfate dose of 500 mg/L as Cu and 72-hour contact time. Scanning electron microscope morphology of C. vulgaris cells confirmed that the cells were ruptured after treatment with copper sulfate. The effect of rupturing increased the lipid extraction yield. For a 10% C. vulgaris paste dosed with copper sulfate at 200 mg as Cu/g of dry algae and 24-hour contact time, the lipid extraction yield increased by 30% with respect to control samples. The specific energy requirement and CO2 emissions per kg of dry algae were estimated as 2.82 MJ and 0.26 kg CO2-eq., respectively. The existing algal cell disruption methods have estimated energy requirements of 10 to 300 times and CO2 emissions of 20 to 600 times greater than those of copper sulfate. Despite these advantages, the adaption of copper sulfate as an algal cell disruption method may be limited by the 24-hour contact time needed to achieve a significant increase in lipid extraction yield. Therefore, it is recommended that future research efforts be focused on addressing this challenge.

Comparación de diferentes métodos de extracción para la determinación del perfil lipídico en semillas de quinoa

In this work, three different methods for the extraction of lipids were compared in quinoa seeds: dynamic maceration with hexane, maceration with hexane assisted by ultrasound and continuous extraction in Soxhlet using an increasing polarity gradient of solvents (hexane, ethyl acetate and methanol). Method performance was evaluated thorough lipid extraction yield and the extracts were subjected to derivatization to generate the corresponding fatty acids methyl esters (FAMEs). All the obtained fractions (the extracts and FAMEs) were analyzed by thin layer chromatography, showing that the extraction methods using hexane as solvent presented spots of similar intensity and retention factor, while the extracts obtained with ethyl acetate and methanol showed spots with different retention factor. The different fractions of FAMEs were analyzed by gas chromatography using flame ionization detector and mass spectrometry, and nuclear magnetic resonance. Using GC-FID the following fatty acids were identified; C14: 0, C16: 0, C18: 0, C18: 1, C18: 2; C18: 3 and C20: 1. The analysis by GC-MS allowed the confirmation of C16: 0; C18: 0; C18: 1; C18: 2.

Lipid Extraction from Spirulina sp. and Schizochytrium sp. Using Supercritical CO2 with Methanol.

Microalgae are one of the most promising feedstocks for biodiesel production due to their high lipid content and easy farming. However, the extraction of lipids from microalgae is energy intensive and costly and involves the use of toxic organic solvents. Compared with organic solvent extraction, supercritical CO2 (SCCO2) has demonstrated advantages through lower toxicity and no solvent-liquid separation. Due to the nonpolar nature of SCCO2, polar organic solvents such as methanol may need to be added as a modifier in order to increase the extraction ability of SCCO2. In this paper, pilot scale lipid extraction using SCCO2 was studied on two microalgae species: Spirulina sp. and Schizochytrium sp. For each species, SCCO2 extraction was conducted on 200 g of biomass for 6 h. Methanol was added as a cosolvent in the extraction process based on a volume ratio of 4%. The results showed that adding methanol in SCCO2 increased the lipid extraction yield significantly for both species. Under an operating pressure of 4000 psi, the lipid extraction yields for Spirulina sp. and Schizochytrium sp. were increased by 80% and 72%, respectively. It was also found that a stepwise addition of methanol was more effective than a one-time addition. In comparison with Soxhlet extraction using methylene chloride/methanol (2:1, v/v), the methanol-SCCO2 extraction demonstrated its high effectiveness for lipid extraction. In addition, the methanol-SCCO2 system showed a high lipid extraction yield after increasing biomass loading fivefold, indicating good potential for scaling up this method. Finally, a kinetic study of the SCCO2 extraction process was conducted, and the results showed that methanol concentration in SCCO2 has the strongest influence on the lipid extraction yield.

Pretreatment and fermentation of salt-water grown algal biomass as a feedstock for biofuels and high-value biochemicals

Utilization of halotolerant algal strains and saline water resources is necessary to increase the areas available for algal cultivation and to mitigate fresh water use issues. However, the added salt content from salt-water algae cultivation may impact downstream biomass pretreatment and conversion processes especially when combined with the salt that is generated as part of our Combined Algal Processing (CAP) scheme which includes pretreatment with sulfuric acid for cell disruption and carbohydrate hydrolysis. Here we compared the pretreatment, fermentation, and lipid extraction processes on salt-water versus fresh-water grown algal biomass. Response surface pretreatment plots showed that a broader range of conditions for the salt-water grown algae species yield >90% sugar yield compared to a narrower range for fresh-water species. Despite this, we anticipated that high salt content would inhibit fermentation of algal sugars, a key element the CAP scheme and sought to reduce the formation of additional salt from pretreatment and neutralization by substituting oxalic acid for sulfuric acid. The sugar release response surface for oxalic acid was of a different shape than that of sulfuric acid but achieved >90% sugar release at 2% acid. Fermentation results showed that for Saccharomyces cerevisiae, the added salts had minimal impact on sugar utilization rates or ethanol production. For Actinobacillus succinogenes however, a significant delay was observed due to the additional salts and fermentation was further delayed or inhibited by pretreatment with oxalic acid. This was remedied by removal of the oxalic acid either by the addition of CaCO3 or trioctylamine whereupon fermentation rates recovered. Differences in lipid extraction yields were observed from the fermentation broth between the salt-water grown and fresh-water grown algal biomass and was species dependent.

Use of cell wall degrading enzymes to improve the recovery of lipids from Chlorella sorokiniana

An enzymatic treatment with cell wall degrading enzymes aimed at improving the recovery of lipids from Chlorella sorokiniana was investigated. Six commercial enzyme preparations containing cellulase, pectinase, lysozyme and three different hemicellulases were preliminary tested. The most effective preparations were then used as basic components for the formulation of enzyme cocktails with high cell wall degrading activity. Experiments were carried out according to the mixture design methodology. Analysis of the results revealed the occurrence of both synergistic and antagonistic effects which were, respectively, attributed to the cooperative destructuring of the cell wall and to non-productive competitive adsorption phenomena. A numerical optimization procedure was used to design an optimal enzyme mixture containing β-1,4-xylanase and β-1,4-mannanase in the ratio of 61:39 (% w/w). Pretreatment of C. sorokiniana by this mixture provided a lipid extraction yield of (74.74 ± 1.02)%. For comparison, the extraction yields from the untreated and water-pretreated biomass were, respectively, equal to (36.19 ± 2.33)% and (58.36 ± 1.22)%.

Extraction, optimization, and characterization of lipids from spent hens: An unexploited sustainable bioresource

Spent hen, a poultry industry by-product with little market value and high lipid content, can be used as a new and sustainable biomass source for lipid production. This study focused on conventional extraction methods and compared them with the microwave-assisted extraction of lipids from the spent hen. Over 95% of the lipids were recovered within 10 min using microwaves. Factors affecting the extraction conditions, including extraction time, temperature, and the solvent-to-feed ratio on the lipid extraction yield were studied using response surface methodology. To account for the low sample size, parametric bootstrapping was used with a replacement approach. Data in all combinations were bootstrapped 10,000 times, which showed a decrease in standard deviation. Fatty acid profiles of extracts obtained in different conditions were investigated using gas chromatography equipped with mass spectrometry and a flame ionization detector for qualitative and quantitative analysis, respectively. The lipids predominantly contained oleic (46%), linoleic (∼22%), and palmitic (∼23%) acids. Proton nuclear magnetic spectroscopy and Fourier transform infrared spectroscopy were used to characterize different functional groups in the lipids. The phase transitions and thermal degradation behavior of lipids were determined using differential scanning calorimetry and thermogravimetric analysis, respectively.

Hydrothermal cell disruption of Nannochloropsis sp. and its influence on lipid extraction

Cell wall disruption is a critical challenge for algal biofuel. Here, we reported Hydrothermal treatment (HTT) of high solid content (20% w/w) Nannochloropsis sp. and its influence on extraction of lipid. Various process variables were specifically studied including reaction temperature (120–200 °C) and retention time (0–60 min). SEM and TEM images revealed the cell morphology before and after HTT. A high extraction yield (84%) of lipid was obtained at 180 °C with a retention time of 60 min, without the use of any catalysts. GC–MS revealed that the main compounds in the extracts were fatty acids, hydrocarbons and esters. UPLC-MS/MS uncovered the detailed varieties of glyceride, phospholipid and glycolipid, and demonstrated that (16:0/16:0/16:1) triglyceride (TAG) was the most abundant TAG. HTT might be a promising method to break microalgae cell wall for lipid extraction.