Methyl Ester Content Research Articles

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.

Characterization of methyl ester compound of Carica papaya seed oil through Transesterification using CaO Catalyst from Strombus canarium shells

Biodiesel is an alternative fuel that is included in renewable energy. Various problems of the source of raw materials for making biodiesel create an opportunity to find alternative sources of raw materials from plant oils, one of which is papaya seeds. Extraction of papaya seeds into oil is carried out by socletation and distillation methods. GCMS analysis showed that papaya seed oil contained oleic acid. Biodiesel transesterification has been carried out using CaO catalyst from the Strombus canarium shells. The reaction was carried out at the papaya seed oil to methanol molar ratio of 1: 6, presence catalyst 5% wt relative to oil and temperature reaction of 65 °C for 2 h. GC/MS analysis result showed that the content of methyl esters is 50.35% with the highest abundance is 10-Octadecenoic acid and the smallest abundance is 9-Octadecenoic acid.

CaO-Nanoparticle-Enriched Polydopamine-Coated Hyper-Crosslinked Polymers as Heterogeneous Catalysts for the Transesterification of Vegetable Oils.

Biodiesel is an alternative fuel produced by the transesterification of vegetable oils in the presence of homogeneous or heterogeneous catalysts. Herein, we report the transesterification of vegetable oils using CaO nanoparticles supported on a polydopamine-coated hyper-crosslinked polymer, CaO@PDA-HCP as a heterogeneous catalyst. The effect of CaO-nanoparticle concentration (5-20 wt%) on catalysis performance was investigated, and the PDA-HCP surface was examined by X-ray diffraction, X-ray photoelectron spectroscopy, Fourier-transform infrared spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, and energy dispersive X-ray spectroscopy. Basicity was shown to greatly influence the methyl ester content, and the best catalyst (15 wt% CaO) was demonstrated to be reusable without any loss of activity.

Biodiesel production from Momordica Charantia (L.): Extraction and engine characteristics

The present research work comprises of the study of Momordica charantia (L.) seeds as an alternative for biodiesel production. A new source of heterogeneous catalyst: duck egg shell derived calcium oxide (CaO), as catalyst is used in the transesterification reaction. The catalyst has been synthesized and analyzed through X-ray diffraction (XRD), Scanning electron microscopy (SEM), Fourier transforms infrared spectrometer (FTIR) and the results were compared with works of other researchers. The MCME thus obtained is characterized through FTIR and Gas chromatograph-Mass spectrometer (GC-MS) for determining the fatty acid methyl ester composition and content. The yield of methyl ester using duck egg shell derived CaO was found to be 96.8%. The engine test at variable engine speed (1200, 1500 and 1800 rpm) and loading (low, medium and full) showed that use of B20 MCME has significant reduction in NOX emissions (51.68%, 55.88% & 55.68% in 1200, 1400 and 1800 rpm) while other emission components- CO, CO2, PM and SO2 were close to that of diesel. Performance and combustion characteristics were observed to be lower than that of diesel.

Lignocellulosic residue as bio-carrier for algal biofilm growth: Effects of carrier physicochemical proprieties and toxicity on algal biomass production and composition

Five types of lignocellulosic materials were applied as the bio-carriers for low-cost algal biofilm cultivation of three algal strains. The effects of bio-carrier physicochemical properties and toxicity on algal cells growth and attachment were investigated. Rougher and hydrophilic bio-carrier could yield more algal biomass than smoother and hydrophobic bio-carrier. Pine sawdust (diameter: 0.420–0.595 mm) performed the best when cultured Diplosphaera sp. (9.61 g·m−2·day−1) biofilm. Meanwhile, bio-carriers could be leached by the culture medium during cultivation, and their energy conversion proprieties could be improved due to the reduced ash contents and the decreased crystallinities. In addition, Chlorella vulgaris growth tests indicated that pine sawdust (15.45%) leachate promoted cell growth, whereas rick husk (15.48%) and sugarcane bagasse (13.19%) leachate inhibited cell growth. And bio-carriers leachates also modified the chemical compositions (lipid, protein and carbohydrate) of algal cells and increased the corresponding saturated fatty acids methyl ester content (from 48.71 to 55.58–57.08%).

Screening of oleaginous algal strains from Chlamydomonas reinhardtii mutant libraries via density gradient centrifugation

Microalgae have a high potential to be utilized as feedstock for biofuels because they have high growth rates and do not compromise food production. Commercialized algae-based biofuel production relies on the development of strains with high lipid content. Based on the relatively low density of lipids compared to other cellular components, density gradient centrifugation was used to isolate high lipid content algal strains from Chlamydomonas reinhardtii mutant libraries. The correlation between cell density and lipid content was confirmed by analysis of Nile red fluorescence intensity, total lipids, and total fatty acid methyl ester content. A strain isolated by this screening method had 50% higher lipid content and 7% lower cell density than the parent wild-type strain. Consequently, we demonstrated that screening of algal strains with low cell density via continuous density gradient centrifugation allows simple, rapid, and inexpensive screening for high lipid content strains.

Bio-catalytic transesterification of mustard oil for biodiesel production

The depletion of non-renewable fossil fuels and a surge in their prices have led researchers to seek alternative, renewable energy sources; among them, biodiesel is a good option, especially in the ever-growing global transport sector. Mustard oil is a potential feedstock for biodiesel production, and because it is non-edible it avoids the food versus fuel feud. Biocatalytic transesterification of mustard oil for biodiesel production makes this process cost efficient, environmentally friendly and sustainable. In the current study, Pseudomanas aeruginosa Q8 KX12304-mediated transesterification of mustard oil was carried out. The parameters for the transesterification reaction were statistically optimized using Plackett–Burman and central composite design. The highest biodiesel volumetric yield obtained was 100% at optimized conditions. The quality of biodiesel was confirmed using gas chromatography–mass spectrometry (GCMS) and the produced biodiesel was found to meet the quality standards specified by American Society for Testing and Materials (ASTM) and EU-14103. The fatty acid methyl ester contents of the biodiesel produced were erucic acid methyl esters (48.2%), palmitic acid methyl esters (11.8%), oleic acid methyl esters (10.6%), linolenic acid methyl esters (10.3%), linoleic acid methyl esters (9.1%) and stearic acid methyl esters (8%). To the best of our knowledge, this is the first study to report transesterification of mustard oil via biocatalysis.

Life cycle assessment of Chlorella species producing biodiesel and remediating wastewater

Constantly rising energy demands, finite fossil fuel reserves and deteriorating environmental conditions have invoked worldwide interest to explore the sustainable sources of renewable biofuels. Locally adapted photosynthetic oleaginous microalgae with rapid growth on variable temperatures could be an ideal way for bioremediating the wastewater (WW) while producing the feedstock for biodiesel. To test this notion, an unknown strain was isolated from a sewage fed lake (Neela-Hauz). It was discerned as Chlorella sorokiniana-I using the 16S rDNA and 18S rDNA barcodes. The culture conditions such as pH, illumination, different temperature ranges and growth medium were cohesively optimized prior to the assessment of C. sorokiniana-I's efficacy to remediate the WWand biodiesel production. The strain has thrived well up to 40°C when continuously grown for 15 days. The highest lipid accumulation and biomass productivity were recorded in 100% WW. Fatty acid methyl ester (FAME) content was observed to be more than twice in WW (47%), compared to control synthetic media, TAP (20%) and BG11 (10%), which indicate the importance of this new isolate for producing economically viable biodiesel. Moreover, it is highly efficient in removing the total nitrogen (77%), total phosphorous (81%), iron (67%) and calcium (42%) from the WW. The quality of WW was considerably improved by reducing the overall chemical oxygen demand (48%), biological oxygen demand (47%) and alkalinity (15%). Thus, C. sorokiniana-I could be an ideal alga for the tropical countries in the remediation of WW while producing feedstock for biodiesel in a cost-effective manner.

Effects of fuel properties on particulate emissions of diesel cars equipped with diesel particulate filters

The current study investigates the effect of diesel fuel density, cetane number (CN), polycyclic aromatic hydrocarbons (PAH) and fatty acid methyl ester (FAME) content on the mass, size distribution, and chemical composition of particulate matter emissions from modern light-duty vehicles. Thirteen test fuels were evaluated against a reference one on chassis dynamometer tests of a (non-DPF) Euro 4 and two DPF-equipped Euro 5 and 6 vehicles. Statistically significant differences in particulate mass (PM) and particle number (PN) emissions were observed between all vehicles, including the two DPF-equipped ones. Fuel properties significantly affected particulate emissions and size distribution in almost all cases of the Euro 4 car, while few statistically significant trends were observed for the Euro 5 and 6 vehicles. High fuel density decreased PN emissions of DPF cars over a cold-start test, while a PN increase was observed for the Euro 6 over the same cycle with increasing FAME content. These effects can be attributed to the impact of density and FAME on engine-out emissions and the subsequent rate of DPF filtration efficiency built-up, following regeneration. Those trends were not observed in hot-start testing after sufficient soot had accumulated in the DPF. Finally, PM chemical composition was found to be insensitive to fuel properties in all vehicles. These results imply that DPFs have to a large extent masked the role of diesel fuel properties on particulate emissions, but there is still room for optimization, especially in PN emissions of vehicles with frequent regenerations.

Dispersed air flotation of Chlorella saccharophila and subsequent extraction of lipids – Effect of supercritical CO2 extraction parameters and surfactant pretreatment

An environmentally sustainable approach was developed for recovering lipids from Chlorella saccharophila for biodiesel production. This involved harvesting the microalgae via foam-aided dispersed air flotation (DiAF) prior to supercritical CO2 (SC–CO2) extraction. Response surface methodology was used to investigate the extraction conditions that would affect the fatty acid composition within the lipids, measured analytically as total fatty acid methyl ester (T-FAME) and biodiesel dominant FAME (BD-FAME) content (% dcw). SC-CO2 extraction parameters for maximum T-FAME (20.4 ± 1.9% dcw) and BD-FAME (9.8 ± 0.4% dcw) content in the extracted lipids were 90 min, 241 bar, 73 °C and 89% moisture (w/w), and 86 min, 241 bar, 73 °C and 86% moisture (w/w), respectively. Further analysis indicated that good T-FAME and BD-FAME content could be achieved when the extraction time was reduced to 30 min without drying, which may be more industrially favorable, as they would reduce processing expenses. Furthermore, the exposure of biomass to surfactant was found to have a significant effect on the composition of FAME in the extracted lipids. Surfactant exposed biomass, resulted in T-FAME and BD-FAME contents of 5.3 and 2.4% (dcw), respectively, and a longer exposure time resulted in higher contents. Centrifuged biomass had a FAME profile most suited for biodiesel. However, surfactant exposure resulted in higher levels of polyunsaturated fatty acids, which could be recovered as high value-added byproducts, and potentially improve the overall process economics. These findings suggest that the lipid composition can be tailored to suit specific applications by adjusting the extraction parameters and surfactant exposure.

Biodiesel production from microbial oil provided by oleaginous yeasts from olive oil mill wastewater growing on industrial glycerol

This study focuses on the potential of four lipogenic yeasts to produce lipids using glycerol as carbon substrate; Candida molendinolei MH267796, Meyerozyma caribbica MH267795 and Rhodotorula minuta MH267794 were isolated from olive oil mill wastewater, while Cryptococcus curvatus ATCC20509 was used as control strain. Lipid production with crude glycerol was higher than that provided with pure glycerol. Fed-batch bioreactor cultures with M. caribbica MH267795 led to the production of 42.12 g L−1 of total dry weight with a microbial oil content of 48.14% (w w−1). In general terms, tested biodiesel properties meet all the limits set by European biodiesel standard UNE 14214:2013, excepting fatty acid methyl ester content. In addition, M. caribbica MH267795 oil biodiesel depicts a fatty acid methyl ester content (90.2% (w w−1)) higher than that of the most intensively studied C. curvatus oil biodiesel. Re-use of crude glycerol as raw material in biodiesel industry has been proven through fermentation, increasing potential full-scale application of such alternative.

Characteristics of direct transesterification using ultrasound on oil extracted from spent coffee grounds

Spent coffee grounds (SCG), the residue after brewing coffee beverage, is a promising biodiesel feedstock due to its high oil contents (15‒20%). However, SCG should be pretreated to reduce the high free fatty acid content, which hampers transesterification reaction. To overcome this, we explored a direct transesterification reaction of SCG using ultrasound irradiation and identified the optimal sonication parameters. A high fatty acid methyl ester (FAME) content, up to 97.2%, could be achieved with ultrasound amplitude of 99.2 <i>μ</i>m, irradiation time of 10 min, and methanol to oil ratio of 7:1 in the presence of potassium hydroxide concentration of 1.25 wt.%. In addition, we demonstrated that ultrasound irradiation is an efficient method to produce biodiesel from untreated SCG in a short time with less energy than the conventional mechanical stirring method. The physical and chemical properties of the SCG biodiesel met the requirements for an alternative fuel to the current commercial biodiesel.

RE-ESTERIFICATION OF MACAUBA ACID OIL USING GLYCEROL FOR ACIDITY REDUCTION AND BIODIESEL PRODUCTION

Abstract Biodiesel production using acid oils is an important alternative for biofuel cost reduction. However, it is a huge challenge for homogeneous transesterification, the main industrial route commonly used. This paper presents macauba oil with high acidity, 43.90 w/w%, as a potential raw material for biodiesel production. The acidity was reduced to 0.8 w/w% after re-esterification (80 min) with glycerol at high temperature (235 °C), without catalysts. Zinc (powder and coating) and NbOPO4 were also tested as catalysts in comparison with the reaction without a catalyst. Reactions catalyzed by metallic Zn produced a large amount of Zn carboxylate, an undesirable soap, due to the high Zn leaching. In contrast with the literature, Zinc did not show good catalytic activity, as confirmed by the kinetic parameters. NbOPO4 was not a good catalyst, too. Reaction without catalysts was performed using nitrogen as a carrier gas and it was compared with reaction under vacuum to remove co-produced water. Nitrogen showed the best result for re-esterification, avoiding degradation reactions. Triglycerides (TG) were the prevalent products in reactions using nitrogen. After re-esterification, the oil was easily converted into biodiesel with high ester content (98.4%) of methyl ester by alkaline transesterification.

Classification of ANFO samples based on their fuel composition by GC–MS and FTIR combined with chemometrics

Ammonium nitrate fuel oil (ANFO) is one of the most favorite explosives used in terrorist attacks. This explosive is a complex mixture of 95–96% ammonium nitrate (AN) and 4–5% liquid hydrocarbons (fuel oil). In this study, we analyze a variety of ANFO explosive mixtures in order to classify their different sources of origin by observing the difference in fuel components. The study was performed by mixing ammonium nitrate with eight different diesel brands collected in Lincoln, UK in two seasons (winter and summer). The samples were extracted using appropriate solvent and extracts were subsequently analyzed in sextuplicate by gas chromatography―mass spectrometry (GC–MS) and Fourier transform infrared spectroscopy (FTIR). A classification model was performed using principal component analysis (PCA) and Lineal Discriminant Analysis (LDA). In this study, four fatty acid methyl ester (FAME) contents were observed by GC–MS in all summer samples but found lack in some winter sample resulting in seasonal variation effect. The classification of pre-blast ANFO samples was achieved using GC–MS and FTIR in a combination with PCA/LDA. The results significantly showed the variation of specific diesel components and providing different classification performance among ANFO samples with high classification performance. Therefore, this study can be beneficial in forensic investigation that the use of diesel components are able to classify among different ANFO samples.

Bench-scale production of sewage sludge derived-biodiesel (SSD-BD) and upgrade of its quality

Even if sewage sludge gain acceptance as a potential feedstock for biodiesel (BD) production, water content and contaminants in sewage sludge still remain as obstacles for the production and quality of biodiesel, respectively. Crude BD was produced from a feedstock of wet sewage sludge with 85% water content via in-situ wet-transesterification in a bench-scale (10 L) reactor, and then further treated for enhancing the BD quality to a transportation grade through a series of refining processes. The wet-transesterification was optimized in terms of crude BD yield by varying methanol dosage, methanol/co-solvent (xylene) ratio and reaction time. The maximum crude BD yield and the fatty acid methyl ester (FAME) content were 11.05 and 67.41%, respectively, when methanol dosage, methanol/co-solvent and reaction time were 15 mL/g, 0.5 and 12 h, respectively. The refining process consisting of vacuum distillation, degumming and neutralization, which satisfied the BD standards (EN14214) and visually improved color and transparency. Based on GC-FID analysis, the FAME content in the refined BD highly increased by eliminating the residual impurities. Applicability of the refined BD as a transportation fuel was confirmed by comparing the quality of the BD blended with the commercial petroleum-diesel (PD) at 3% (BD3) with the standard specification.

A novel approach using low-cost Citrus limetta waste for mixotrophic cultivation of oleaginous microalgae to augment automotive quality biodiesel production

The present study reports the use of Citrus limetta (CL) residue for cultivating Chlorella sp. mixotrophically to augment production of biodiesel. The cultivation of Chlorella sp. using CL as media was carried out by employing a fed-batch technique in open tray (open tray+CL) and in software (BioXpert V2)-attached automated photobioreactor (PBR+CL) systems. Data showed the limit of nitrogen substituent and satisfactory organic source of carbon (OSC) in CL, causing > 2-fold higher lipid content in cells, cultivated in both the systems than in control. For the cells grown in both the systems, ≥ 3-fold enhancement in lipid productivity was observed than in control. The total fatty acid methyl ester (FAME) concentrations from lipids extracted from cells grew in PBR+CL and in open tray+CL techniques were calculated as 50.59% and 38.31%, respectively. The PBR+CL system showed improved outcomes for lipid content, lipid and biomass productivity, FAME characteristics and physical property parameters of biodiesel than those obtained from the open tray+CL system. The physical property parameters of biodiesel produced from algal cells grown in PBR+CL were comparable to existing fuel standards. The results have shown lower cold filter plugging point (- 6.57 °C), higher cetane number (58.04) and average oxidative stability (3.60 h). Collectively, this investigation unveils the novel deployment of CL as a cost-effective feedstock for commercialisation of biodiesel production.

Co-production of biodiesel and alginate from Laminaria japonica

A process to produce both biodiesel and alginate in an integrated manner from a brown seaweed, Laminaria japonica, was established. Mannitol, a major carbon constituent in L. japonica, served to produce neutral lipids via the heterotrophic cultivation of an oleaginous yeast, Cryptococcus sp.; and simultaneously alginate, a high value product, was extracted to enhance the economic feasibility of the entire process. Only autoclave pretreatment, without need of any chemical agents, was enough to recover all the essential nutrients for the yeast cultivation. Specifically, it could recover 6.4 g L−1 of mannitol to a degree comparable to 6.6 g L−1 obtained by acid-aided pretreatment using 1.5% (v/v) of H2SO4. Maximum fatty acids methyl esters (FAME) content was 30.37% with FAME productivity of 0.56 g L−1 d−1, and the produced FAME could meet the biodiesel quality standards. Na2CO3-based method showed the best efficiency of alginate recovery, yielding 21.06% (w/w). This study supports that L. japonica can indeed be a promising low-cost feedstock for biodiesel production, and it is more so when a high-value product alginate is co-produced.

Influence of hexanol as additive with Calophyllum Inophyllum biodiesel for CI engine applications

In the present work, an experiment on ternary blends made of n-hexanol, diesel and Calophyllum Inophyllum methyl ester was conducted to compare the emission, performance and combustion characteristics to that of pure diesel and Calophyllum Inophyllum methyl ester. In the present research work, all the ternary blends were prepared by keeping the diesel weight percentage as a constant at 50% by volume, the Calophyllum Inophyllum methyl ester and hexanol concentrations were varied by volume and the developed blends were used for the comprehensive analysis. The brake thermal efficiency was observed to be significantly higher for the hexanol blends; especially for 40% hexanol is closer to that of pure diesel at elevated brake mean effective pressures. Also, the brake specific fuel consumptions are observed to be lower than that of pure CIME. Emissions such as hydrocarbon, smoke opacity and carbon monoxide were found to be significantly lower than the diesel. However, the NOx and carbon dioxide emissions for alcohol blends remained marginally higher compared to diesel. A significant improvement in the combustion characteristics such as the in-cylinder pressures and net HRR figures were observed when compared to pure biodiesel. Therefore, from the results, it is recommended that the 30% and 40% of n-hexanol blends with further study can suitably be a potential alternative for pure diesel.

Synthesis and catalytic evaluation of hematite (α-Fe2O3) magnetic nanoparticles from iron sand for waste cooking oil conversion to produce biodiesel through esterification-transesterification method

Indonesia’s catalyst needs to reach 2000 tons/year with active period of 1 up to 2 years. The catalyst requirement is largely filled with import catalysts. Iron sand has a potential to be used as a catalyst mainly because of the hematite magnetic mineral content (α-Fe2O3). α-Fe2O3 can be synthesized from iron sand using coprecipitation and calcination method. Performance of these synthesized catalyst evaluated through the production of biodiesel from waste cooking oil by esterification-transesterification method. The catalyst preparation by chemical coprecipitation method followed with calcination. Catalyst was characterized by using XRD, SEM-EDX, BET, and PSA and tested for biodiesel production. α-Fe2O3 phase was obtained at calcination temperature 650°C, 700°C, 750°C and 800°C. The best character is given at temperature 700°C. Biodiesel obtained meets SNI (Standar Nasional Indonesia) based on density, viscosity, and acid number. Yield of biodiesel obtained by using α-Fe2O3 calcined at 700°C reaches 86.781% while Fatty Acid Methyl Ester (FAME) content obtained reaches 87.880%.

Evaluation of dolomite as catalyst in the transesterification reaction using palm oil (RBD)

In this study, the catalytic activity of dolomite was evaluated for the transesterification of Colombian RBD palm oil with methanol, carried out in a batch reactor at 333,15K and 600rpm. The activated dolomites (calcined at 1073.15K for 2h) were characterized by scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR), Hammett indicators method, and quantification of the surface area, average pore size and average pore volume BET. The influence of reaction variables such as catalyst amount (%wt /wt) and methanol / palm oil molar ratio (mole/mole) was investigated. Under the suitable reaction conditions, the amount of calcined dolomite equal to 4% (wt /wt) based on the weight of oil, the methanol-oil molar ratio equal to 9:1, and the reaction time = 1h, the methyl ester content of 82.67% of fatty acid methyl esters (FAME) can be achieved.