Optimization of algal lipid extraction by mixture of ethyl acetate and ethanol via response surface methodology for biodiesel production

The effects of extraction time, extraction temperature, solvent to biomass ratio and solvent composition on lipid yield from lyophilized Chlorococcum sp. biomass using a mixture of ethyl acetate and ethanol (EAE), a new proposed solvent, were studied. Subsequently, the process conditions of extraction by EAE were optimized using Box-Behnken design (BBD). The results revealed that the extraction temperature had the greatest effect on lipid extraction efficiency, followed by volume ratio of ethyl acetate to ethanol (EA/E) and extraction time. The largest lipid extraction yield of 15.74% was obtained under the following extraction conditions: 40mL solvents per gram of biomass for 270 min with gentle stirring at 80 °C by EAE with an EA/E of 1.0. Furthermore, palmitic acid, stearic acid, oleic acid, and linoleic acid were the most abundant fatty acids in the lipids extracted, indicating the great potential of the proposed lipid extraction procedure for microalgae-based biodiesel production.     

Solvent Extraction of Biologically Derived 1,3-Propanediol with Ethyl Acetate and Ethanol Cosolvent

This study examined the use of ethyl acetate and its mixture with ethanol as cosolvent for the extraction of biologically derived 1,3-propanediol (1,3-PDO) from a fermentional process. Experimental results on extraction of the fermentation model mixture revealed that ethyl acetate was a suitable solvent, having the distribution coefficient of 1,3-PDO of 0.22 at 303.15 K. The temperature (303.15 to 323.15 K) was found not to have a significant effect on the distribution coefficient. On the other hand, the addition of glycerol into the feed aqueous stream (at the concentrations of 4, 8, 12 g/L) was found to increase the distribution coefficient of 1,3-PDOs, however, the compound selectivity decreased. When ethanol was used as a cosolvent at the volume ratio of ethyl acetate to ethanol of 90:10, the distribution coefficient increased from 0.22 to 0.31 at 303.15 K. This decreased the number of theoretical stages (NTS) required to achieve 90% recovery of 1,3-PDO from the aqueous phase from 3 to 2 stages at the solvent to feed (S/F) ratio of 9. In addition, the extraction results with actual fermentation broth at 303.15 K indicated that the use of ethanol cosolvent could improve the distribution coefficient of 1,3 PDO from 0.14 to 0.20.     

Optimization of Microwave‐Assisted Extraction of Flavonoid from Radix Astragali using Response Surface Methodology

Abstract

Response surface methodology (RSM) was applied to predict optimum conditions for microwave‐assisted extraction (MAE) of flavonoid from Radix Astragali. A central composite design was used to monitor the effect of temperature, extraction time, solvent‐to‐material ratio, and the ethanol concentration on yield of total flavanoid (TFA). Optimum extraction conditions were predicted as 108.2°C, 26.7 min, 23.1 ml/g solvent‐to‐material ratio and 86.2% ethanol. The maximum yield 1.234±0.031 mg/g was close to the yield of Soxhlet and higher than that of ultrasound assisted extraction and heat reflux extraction. MAE was an effective alternative to conventional extraction methods.     

选择性溶剂萃取生产低凝柴油的溶剂筛选和溶剂选择性的表征

酮类、酯类、氯代烃类溶剂分别对减一线油和常三线油进行了选择性萃取生产低凝柴油的实验。溶剂乙酸乙酯的选择性好,可降低减一线油和常三线油冷滤点分别为18°C和16°C,同时对柴油燃烧性能的影响较小,是选择性萃取生产低凝柴油的最佳溶剂。比较了各溶剂的脱蜡率、脱出的各碳数正构烷烃的质量分布和脱蜡油的冷滤点,引入了由高碳数正构烷烃脱出量、脱蜡率和冷滤点降低值三个因子组成的综合评价参数。该参数能表征本工艺要求的选择性,并直观地指导对两种油样均优的萃取溶剂的选择。     

Extraction of Hydrocarbons from Crude Oil Tank Bottom Sludges using Supercritical Ethane

Abstract

A custom‐built, solvent recirculating, supercritical fluid extraction (SFE) apparatus was used to study the extraction of hydrocarbons from a crude oil tank bottom sludge (COTBS) with supercritical ethane. The SFE experiments were carried out varying the pressure (10 MPa and 17.20 MPa) and temperature (35°C and 65°C). The yield of the extracted hydrocarbon fraction increased with increase in extraction pressure at constant temperature, and decreased with increase in extraction temperature at constant pressure. The maximum extraction yield was obtained at the pressure and temperature conditions that lead to the highest solvent density. The extracted hydrocarbon fraction was a significantly upgraded liquid relative to the original untreated COTBS.     

γ-Oryzanol Recovery from Rice Bran Oil Soapstock

The suitable conditions were determined for the recovery of high-value antioxidative compound, γ-oryzanol, from low cost rice bran soapstock by-product of the rice bran oil industry. First, soapstock was saponified and was then dehydrated and extracted with ethyl acetate. The extract was further purified by crystallization twice in appropriate solvent systems. At the most suitable conditions, using 20% v/v of ethyl acetate in methanol, and at 30°C and 1 h for the first crystallization step, and 5°C and 24 h for the second, the yield and purity of γ-oryzanol were 55.17 ± 0.59 wt% and 74.60 ± 4.12 wt%, respectively.     

Effect of ultrasound- and pulsed electric field-assisted enzymatic treatment on the recovery and quality of sunflower oil

The aim of this study was to evaluate the effect of cavitation and electroporation on enzymolysis extraction of sunflower oil. The optimum extraction conditions during 2 h under enzyme-assisted extraction (EAE) with a maximum oil yield of ≈23.70 ± 0.11% were as follows: cellulase/pectinase ratio 2:1, enzyme concentration 2%, pH 4.5, liquid/solid ratio 6:1 ml/g, and extraction temperature 40°C. Under the optimized enzymatic conditions, the application of ultrasound- (250 W) and pulsed electric field- (1.2 kV/cm; 52.4 kJ/kg) assisted enzymatic extraction for 30 min significantly increased the oil extraction yield by 91.1% and 18.6%, respectively, as compared with EAE.     

Studies on Bi-Cyclic Aromatics Extraction using Furfural and N-Methyl Pyrrolidone (NMP) as Solvent

In this work, the separation of naphthalene, a bicyclic aromatic component, by the solvent extraction method from a model oil (p-xylene, iso-octane, and naphthalene) using furfural and n-methyl pyrrolidone (NMP) as solvent has been investigated. A four factor Box-Behnken design was used to study the individual and interactive effects of four main parameters namely paraffinic content in model oil (P/F): 0.7–0.8; solvent to feed ratio (S/F): 0.5–1.0; temperature (T): 20–40°C; time (t): 1–3 h for furfural and 1–7 h for NMP on the yield and selectivity of naphthalene. Gas chromatography was carried out to analyze the composition of raffinate and extract phases. Various polynomial models were fitted to find out the best model for the system. Pareto analysis of variance (ANOVA) and other statistical tests were performed to check the significance of the model. Furfural was found to be a better solvent as compared to NMP, both in terms of yield and selectivity. The operating conditions leading to maximum aromatic recovery have been optimized. The optimum conditions for furfural was found to be P/F = 0.7, S/F = 0.5, temperature = 24°C and time = 3 h whereas the optimum conditions for NMP were: P/F = 0.76, S/F = 0.76, temperature = 22°C, and time = 4.1 h.     

Extraction of caffeine from natural matter using a bio-renewable agrochemical solvent

This paper reports experimental data on the pressurized liquid extraction of caffeine from green coffee beans and green tea leaves using ethyl lactate (ethyl 2-hydroxy-propanoate). This solvent is a new bio-renewable agrochemical solvent, naturally produced by fermentation from corn derived feedstock, which has been recently considered as a very suitable and environmental benign solvent for food industrial applications.Static extraction assays (one step during 10 min) were carried out in an Accelerated solvent extraction (ASE) system at three different extraction temperatures, namely 100, 150 and 200 °C. Extraction yield and caffeine recovery were determined and compared with those obtained when using other liquid solvents, such as ethyl acetate or ethanol. High recovery of caffeine (≈60%) was found in the extracts produced using ethyl lactate, which demonstrates the potential use of this green solvent for the extraction of caffeine from different vegetable sources.     

马占相思树皮中原花色素提取工艺及其生物活性的研究

通过正交试验优化了马占相思树皮中原花色素的3种提取方法的最佳提取工艺条件。结果显示,传统溶剂提取法的最佳工艺为：60%乙醇、70℃、70 min、料液比1∶18（g∶mL,下同）,原花色素得率为7.42%;微波辅助提取法的最佳工艺条件为：60%乙醇、微波功率200 W、微波时间8 min、料液比1∶18,得率为7.05%;超声波辅助提取法的最佳工艺为：70%乙醇、超声波温度50℃、超声波时间50 min、料液比为1∶16,得率为8.57%。超声波辅助提取法效果最好,浸提温度低,得率高。进一步对超声波提取物不同溶剂萃取物的体外抗氧化活性和抗肿瘤活性进行了研究。结果表明,乙酸乙酯萃取物对DPPH·清除效果最好,其半数抑制浓度（IC₅₀）为17.94 mg/L,低于对照样维生素C（Vc）的IC₅₀值;乙酸乙酯萃取物对人肝癌细胞Bel-7404具有明显的抑制效果,IC₅₀值为4.86 mg/L,与抗肿瘤药依托泊苷效果相当。     

Pilot-Scale Multi-Stage Countercurrent Extraction of Scutellarein from Erigeron breviscapus (Vant.) Hand-Mazz

Abstract

A low-temperature, timesaving, lower solvent consumption, and energy cost and multi-stage countercurrent extraction (MCCE) technique was developed for pilot-scale production of scutellarein from Erigeron breviscapus (Vant.) Hand-Mazz. The optimum conditions of MCCE process were obtained using the orthogonal array design method, i.e., 70% (v/v) of ethanol water solution, 16 L/kg of solvent to herbal sample ratio, 45°C of extraction temperature and 30 min of extraction time. A comparison between the MCCE technique and single pot extraction (SPE) under respective optimized operation conditions was made and time courses of scutellarein of MCCE and SPE processes were plotted, indicating that the MCCE technique can lower the extraction temperature and decrease five-sixth of the extraction time and two-thirds of the solvent consumption at the equivalent extraction yield of scutellarein.     

Extraction of Total Phenolics of Sour Cherry Pomace by High Pressure Solvent and Subcritical Fluid and Determination of the Antioxidant Activities of the Extracts

Abstract

High pressure liquid extraction (HPE) and subcritical fluid (CO₂+ethanol) extraction (SCE) were used for the extraction of total phenolic compounds (TPC) from sour cherry pomace. Antiradical efficiency (AE) of the extracts was also determined. Ethanol was the solvent for HPE and co‐solvent for SCE. Combinations of pressure (50, 125, 200 MPa), temperature (20, 40, 60°C), solid/solvent ratio (0.05, 0.15, 0.25 g/ml) and extraction time (10, 25, 40 min) were variables for HPE according to the Box‐Behnken experimental design. The variables used for SCE were pressure (20, 40, 60 MPa), temperature (40, 50, 60°C), ethanol concentration (14, 17, 20 wt%) and extraction time (10, 25, 40 min). For HPE, TPC, and AE at the optimum conditions (176–193 MPa, 60°C, 0.06–0.07 g solid/ml solvent, 25 min) were found as 3.80 mg gae/g sample and 22 mg DPPH^?/g sample, respectively. TPC and AE at the optimum conditions (54.8–59 MPa, 50.6–54.4°C, 20 wt% ethanol, 40 min) for SCE were determined as 0.60 mg gae/g sample and 2.30 mg DPPH^?/g sample for sour cherry pomace, respectively.     

Comparison of Ethyl Acetate with Hexane for Oil Extraction from Various Oilseeds

The aim of the current research was to determine a less hazardous, cheaper and less toxic alternative solvent for hexane for extraction of oil from different oilseeds showing equivalent oil yield and oil quality. A full factorial design with three levels of extraction temperature (80, 100 and 120 °C) and three levels of extraction time (40, 65 and 90 min) with constant solvent to seed ratio value of 4:1 was used to extract the oil. Maximum oil was recovered from canola followed by flax, mustard and camelina. The oil content of canola was found in range of 21.08–36.44, and 25.12–40.38 % for hexane and ethyl acetate, respectively. The heating values of oil extracted from all oilseeds using hexane and ethyl acetate were found in the range of 38.04–39.98 and 37.98–39.37 MJ/kg, respectively. Least viscosity was found for flax seed using hexane followed by camelina, canola and mustard as compared to ethyl acetate. Viscosity of flax oil ranged from 27.23–37.19, and 31.16–55.52 cP for hexane and ethyl acetate solvents, respectively. Considering human safety, less environmental impact, comparable oil yield and quality parameters, ethyl acetate can be a promising alternative to hexane.     

Response Surface Methodology to Supercritical Carbon Dioxide Extraction of Essential Oil from Amormum krevanh Pierre

Abstract

Response surface methodology was employed to investigate the effects of operating conditions and predict the optimal conditions for supercritical carbon dioxide extraction of essential oil from Amomum krevanh Pierre. The factors investigated were operating temperature (33–67°C), the operating pressure (91–259 bar), and the extraction time (20–70 min). The main effect of the operating pressure and the interaction effect between the operating temperature and the extraction time were found to be significant factors. From the response surface model, an optimal condition for essential oil content within the range of experimental study was found to be at 33°C, 175 bar, and 70 min, which gave the oil yield of 17.3 mg/g dry wt. The essential oil yield obtained at all conditions were higher than that obtained by organic solvent extraction (9.74 mg/g dry wt.) while the composition of the extract was similar, which were 1,8-cineole (70.87%), β-pinene (8.89%), and limonene (4.81%).     

Optimization of ultrasound-assisted extraction of bioactive compounds from B. forficata subsp. Pruinosa

Extracts containing bioactive compounds were obtained from Bauhinia forficata leaves by ultrasound-assisted extraction (UAE) with three different solvents (n-hexane, ethyl acetate, and ethanol) and were compared with those obtained by a conventional method (maceration). Box-Behnken experimental design was applied to examine and optimize the effect of the extraction temperature (40°C-60°C), power (20%-80%), and sample to solvent ratio (1:10 to 1:20 (w/v)) on the total phenolic content (TPC), total flavonoid content (TFC), and the ferric reducing antioxidant power (FRAP) of B. forficata leaf extracts. This experimental design generated second-order polynomial models, which accurately describe the experimental data, allowing the prediction of optimal conditions for the investigated responses. Optimal extraction was achieved under the following conditions: 80% power, temperature of 41°C, and a 1:20 sample to solvent ratio. Under these conditions, the experimental yield was 8.33 ± 0.32%, total phenolic content was 59.47 ± 0.71 mg GAE · g_extract⁻¹, total flavonoid content was 62.30 ± 3.38 mg QE · g_extract⁻¹, and the ferric reducing antioxidant power was 726.7 ± 15.7 μmol Fe(II)EQ · g_extract⁻¹, which were close to the predicted values, which validated the models. The major compounds found in B. forficata extracts were tocopherols, phytol, heneicosane, and β-Sitosterol.     

Kariya (Hildegardia barteri) seed oil extraction: comparative evaluation of solvents,modeling, and optimization techniques

In this work, the effects of solid/solvent ratio (0.10–0.25?g/ml), extraction time (3–8?h), and solvent type (n-hexane, ethyl acetate, and acetone) together with their shared interactions on Kariya seed oil (KSO) yield were investigated. The oil extraction process was modeled via response surface methodology (RSM), artificial neural network (ANN) and adaptive neuro-fuzzy inference system (ANFIS) while the optimization of the three input variables essential to the oil extraction process was carried out by genetic algorithm (GA) and RSM methods. The low mean relative percent deviation (MRPD) of 0.94–4.69% and high coefficient of determination (R²) > 0.98 for the models developed demonstrate that they describe the solvent extraction process with high accuracy in this order: ANFIS, ANN, and RSM. The best operating condition (solid/solvent ratio of 0.1?g/ml, extraction time of 8?h, and acetone as solvent of extraction) that gave the highest KSO yield (32.52?wt.%) was obtained using GA-ANFIS and GA-ANN. Solvent extraction efficiency evaluation showed that ethyl acetate, n-hexane, and acetone gave maximum experimental oil yields of 19.20?±?0.28, 25.11?±?0.01, and 32.33?±?0.04?wt.%, respectively. Properties of the KSO varied based on the type of solvent used. The results of this work showed that KSO could function as raw material in both food and chemical industries.     

Optimization of Ultrasound-Assisted Extraction of Artemisinin from Artemisia annua L. by Response Surface Methodology

Artemisinin is a compound extracted from Artemisia annua L. with a remarkable curative effect against malaria. It can be extracted using ultrasound-assisted extraction (UAE) and then detected via HPLC. In this study, response surface methodology (RSM) was used to optimize UAE conditions for obtaining the maximum yield of artemisinin. Three independent variables (ratio of solvent to material, extraction temperature, and ultrasonic power) were evaluated using the Box-Behnken experimental design, with the yield of artemisinin as a response variable. Experimental data were highly fitted to a mathematical-regression model using multiple linear regression (MLR). Based on response surface plots, the three independent variables exhibited interactive effects on the yield of artemisinin. The optimal extraction conditions were as follows: 42.71 mL/g ratio of solvent to material, 41.86°C extraction temperature and 120 W ultrasonic power. The predicted yield of artemisinin by model was 0.7848%, whereas the actual yield in the extracts was 0.7826% ± 0.0790% in adjusted optimal conditions, with a relative error of 0.28%. The results undoubtedly demonstrated that RSM could be used to explore the optimum conditions of artemisinin extraction.     

Impact of ultrasound on oil yield and content of functional food ingredients at the oil extraction from sunflower

In this study, the effect of ultrasound-assisted extraction (UAE) on oil yield and content of functional food ingredients of hulled and non-hulled sunflower is discussed and compared with conventional extraction methods. The optimum extraction parameters for UAE were as follows: n-hexane as extracting solvent, average particle size 250 ± 12 µm, extraction time 2 h, solid-to-solvent ratio 1:12, ultrasound frequency 24 kHz and temperature 50°C. Furthermore, the chromatograph showed that sunflower oil extracted by the UAE was rich in α-Linolenic acid (ω-3). In addition, a marginal reduction in peroxide values and tocopherols were determined.     

Ultrasound-assisted extraction of natural antioxidants from betel leaves (Piper betle): Extraction kinetics and modeling

Present study investigated the extraction kinetics of antioxidants from Piper betle by ultrasound-assisted extraction for three extraction variables: temperature, solute to solvent ratio and ethanol concentration. Based on the results of yield, total phenolic content and antioxidant activity, the optimum results were obtained at 50°C, 1:20 g/mL and 80% ethanol, respectively. Statistical coefficients of R² ≥ 0.961 and RMSE ≤ 0.508 for two-site kinetic model confirm the use of proposed models for simulation and prediction purpose. Comparison with ascorbic acid and butylated hydroxytoluene solidifies the use of Piper betle as feasible source of natural antioxidants. The presence of hydroxychavicol and eugenol was affirmed by high-performance liquid chromatography assay.     

巨尾桉叶中原花色素提取工艺比较及不同溶剂萃取物生物活性的研究

通过正交试验探讨了巨尾桉叶中原花色素的3种提取方法的最佳提取工艺条件,并进行了对比。结果显示,传统溶剂提取法的最优工艺为:60%乙醇、80 ℃、100 min、料液比1:14(g:mL,下同),原花色素得率5.95%;微波辅助提取法的最优工艺为:50%乙醇、微波功率200 W、微波时间4 min、料液比为1:20,得率5.48%;超声波辅助提取法的最优工艺为:60%乙醇、60 ℃、超声波时间25 min、料液比为1:14,得率为6.07%。超声波辅助提取法效果最好,时间短,得率高。实验对超声波提取物的不同溶剂萃取物体外抗氧化性和抗肿瘤活性进行了研究,结果表明,乙酸乙酯萃取物抗氧化作用较强,当质量浓度为1.2 g/L时,对DPPH自由基清除率达到96.33%;乙酸乙酯萃取物质量浓度为2 g/L时,对于人肝癌细胞Bel-7404具有很强的抗肿瘤活性,抑制率为56.37%。