Saturated Fatty Acid Methyl Esters Research Articles

Microbial dynamics, chemical profile, and bioactive potential of diverse Egyptian marine environments from archaeological wood to soda lake

Halophilic archaea are a unique group of microorganisms that thrive in high–salt environments, exhibiting remarkable adaptations to survive extreme conditions. Archaeological wood and El–Hamra Lake serve as a substrate for a diverse range of microorganisms, including archaea, although the exact role of archaea in archaeological wood biodeterioration remains unclear. The morphological and chemical characterizations of archaeological wood were evaluated using FTIR, SEM, and EDX. The degradation of polysaccharides was identified in Fourier transform infrared analysis (FTIR). The degradation of wood was observed through scanning electron microscopy (SEM). The energy dispersive X–ray spectroscopy (EDX) revealed the inclusion of minerals, such as calcium, silicon, iron, and sulfur, into archaeological wood structure during burial and subsequent interaction with the surrounding environment. Archaea may also be associated with detected silica in archaeological wood since several organosilicon compounds have been found in the crude extracts of archaeal cells. Archaeal species were isolated from water and sediment samples from various sites in El–Hamra Lake and identified as Natronococcus sp. strain WNHS2, Natrialba hulunbeirensisstrain WNHS14, Natrialba chahannaoensis strain WNHS9, and Natronococcus occultus strain WNHS5. Additionally, three archaeal isolates were obtained from archaeological wood samples and identified as Natrialba chahannaoensisstrain W15, Natrialba chahannaoensisstrain W22, and Natrialba chahannaoensisstrain W24. These archaeal isolates exhibited haloalkaliphilic characteristics since they could thrive in environments with high salinity and alkalinity. Crude extracts of archaeal cells were analyzed for the organic compounds using gas chromatography–mass spectrometry (GC–MS). A total of 59 compounds were identified, including free saturated and unsaturated fatty acids, saturated fatty acid esters, ethyl and methyl esters of unsaturated fatty acids, glycerides, phthalic acid esters, organosiloxane, terpene, alkane, alcohol, ketone, aldehyde, ester, ether, and aromatic compounds. Several organic compounds exhibited promising biological activities. FTIR spectroscopy revealed the presence of various functional groups, such as hydroxyl, carboxylate, siloxane, trimethylsilyl, and long acyl chains in the archaeal extracts. Furthermore, the archaeal extracts exhibited antioxidant effects. This study demonstrates the potential of archaeal extracts as a valuable source of bioactive compounds with pharmaceutical and biomedical applications.

Biodiesel derived from the microalgae Nannochloropsis gaditana and Haematococcus pluvialis: Physicochemical and tribological properties

The physicochemical and tribological propertie of two biodiesels derived from Nannochloropsis gaditana and Haematococcus pluvialis microalgae were evaluated, and the impact of their fatty acid methyl esters (FAMEs) on the aforementioned properties was also evaluated. The H. pluvialis biodiesel exhibited reduced friction and wear compared to the N. gaditana counterpart, attributed to its lower degree of unsaturation and higher content of chain length of 17–18, which enhances the adsorption of stronger and thicker tribofilms. Additionally, the higher ratio of monounsaturated to total saturated FAME content contributed to this outcome. The content of polyunsaturated fatty acids decreased the viscosity and increased the end thermal degradation temperature.

Total Lipid Content and Fatty Acid Composition of Two Morphologically Distinct Chlorella spp. for Biodiesel Production

This study investigated the potential of two morphologically distinct Chlorella spp. to assess the total lipid content and fatty acid composition targeting biodiesel production. Due to their rapid growth, less space requirement, and zero-conflict with current food demand, green microalgae-led biodiesel production has gained a key attention as an alternative, sustainable and eco-friendly substitute for fossil fuels diminishing the increased demand for fossil fuels, fuel prices and excessive release of greenhouse gases to the atmosphere. The Chlorella spp. were isolated from Beire Lake, Colombo (Wet Zone) and Kiriibban Lake, Monaragala (Dry Zone) of Sri Lanka. They were named as BCS1 and RCS2, respectively. Semi-mass culturing of Chlorella spp. in BG-11 medium (pH=7.5-8.5) was carried out in a greenhouse providing aeration and a 12:12 light: dark photoperiod. After 4 weeks, Chlorella spp. were harvested using aluminium sulphate, employing flocculation method. Harvested biomass was oven-dried and made into a fine powder for analysis. The total lipid content (TLC) of Chlorella spp. was determined using n-hexane as the extraction solvent in a soxhlet extractor maintaining three replicates for each. Extracted lipids were dried in a rotary evaporator and TLC was calculated gravimetrically. The total lipid content of BCS1 and RCS2 was recorded as 15.67% and 18.33%, respectively. After quantification, lipids were resuspended and concentrated in 1 mL of n-hexane to convert into fatty acid methyl esters (FAMEs)/ biodiesel via a transesterification reaction. The trans-esterified lipids (FAMEs) were analysed via Gas Chromatography. The most dominant FAMEs of BCS1 were palmitic acid (C16:0), oleic acid [C18:1 cis (n9)], stearic acid (C18:0), lignoceric acid (C24:0), lauric acid (C12:0) and myristic acid (C14:0). The most dominant FAMEs of RCS2 were cis-10-pentadecenoic acid (C15:1), elaidic acid [C18:1 trans (n9)], linolelaidic acid [C18:2 trans (n6)], cis-11-eicosenoic acid [C20:1 (n9)], lignoceric acid (C24:0) and oleic acid [C18:1 cis (n9)]. A well-balanced saturated and unsaturated FAME composition is essential for the optimal biodiesel quality, herein it was found in BCS1 with 41.62% of palmitic acid and 33.38% of oleic acid. Higher percentage of oleic acid exhibits a combination of oxidative stability and low temperature properties determining the suitability of BCS1 as a biodiesel feedstock compared to RCS2. In conclusion, even though RCS2 has a higher total lipid content, BCS1 exhibits more favourable characteristics in its FAME composition as a promising feedstock for biodiesel production.
 
 Keywords: Green microalgae, Chlorella spp., Total lipid content, Lipid composition, Biodiesel

The vaporization enthalpies and vapor pressures of Vescepa® and related unsaturated marine FAME by correlation gas chromatography

This article combines data from two previous reports together with new data dealing with the vaporization enthalpies and vapor pressures of a series of saturated and unsaturated fatty acid methyl ester(s) (FAME) by correlation gas chromatography. The work updates earlier results using newly proposed vaporization enthalpies for the saturated FAME used as standards in previous work. This update also provides some insight into the requirements necessary for appropriate column and standard selection for experiments using correlation gas chromatography. Vaporization enthalpies and vapor pressures for saturated FAME methyl heneicosanoate, methyl docosanoate, and methyl tetracosanoate are re-evaluated and together with proposed literature values for methyl tetradecanoate to methyl eicosanoate, are used to evaluate similar properties for a series of unsaturated fatty acid esters. Updated results on the vaporization enthalpies and vapor pressures of a number of unsaturated fatty acid methyl esters (FAME) found in marine oil are reported including several relatively reactive omega-3-polyunsaturated esters. Omega-3-FAME include methyl (9,12,15)Z-octadecatrienoate, methyl (5,8,11,14,17)Z-eicosapentaenoate, and methyl (4,7,10,13,16,19)Z-docosahexenoate among other unsaturated methyl esters. Also included in the study of the omega-3-unsaturated esters is the drug Vescepa®, ethyl (5,8,11,14,17)Z-eicosapentaenoate, a drug used to lower triglyceride levels.

High-pressure phase equilibrium data for the carbon dioxide + methyl esters homologous series and SAFT-VR Mie modelling

High-pressure phase transition data measured using a visual static synthetic method are presented for various CO2 + saturated fatty acid methyl ester systems in the range 308–358 K and up to 27.5 MPa. The newly measured data cover methyl esters between methyl decanoate and methyl docosanoate in the liquid-like, mixture critical and vapour-like regions, and complement previously published data. The systems studied do not suggest three-phase behaviour, liquid-liquid immiscibility or temperature inversions in the temperature range considered. An increase in temperature and molecular mass of the methyl ester leads to an increase in the phase transition pressure. The SAFT-VR Mie equation of state was able to correlate the data well with decreasing performance at higher methyl ester molecular masses and lower temperatures.

Cultivation of Chlorella minutissima under a novel phosphate application strategy for biodiesel production: A pilot scale study

Microalgal biodiesel is considered as a carbon-neutral and renewable energy source for replacing/blending with petroleum-based diesel fuel. Selection of a microalgal species for its potential to produce biodiesel relies significantly on its acclimatization to grow in outdoor condition with high lipid productivity. The present investigation undertakes outdoor experiments in a raceway pond system involving a local isolate of green microalga, Chlorella minutissima, throughout varied seasonal changes and culture depth. The variations in climatic and cultural parameters were documented; the optimum culture depth of 30 cm was taken for further investigation. A novel cultivation approach incorporating the sequential addition of low-dose phosphate (LDSPA) projected a lipid productivity of 5.88 ton hectare−1 year−1, which was ∼40% higher than its batch culture counterpart, along with a 14-fold reduction in phosphate application. The biodiesel exhibited the dominance of saturated and monounsaturated fatty acid methyl esters, and the fuel qualities were confirmed to be within the stipulated limitations of European, American and Indian biodiesel standards, thus nominating C. minutissima as an attractive feedstock for generating high-quality biodiesel.

Optimization of microwave-assisted biodiesel production from watermelon seeds oil using thermally modified kwale anthill mud as base catalyst

A heterogeneous catalyst was developed from raw Kwale red Anthill mud by thermal treatment in a muffle furnace at 900 °C for 4 h. The resulting heterogeneous catalyst was highly porous with a surface area of 42.16m2/g, possessing excellent stability as well as high catalytic activity. Central Composite Design and Machine Learning approach (Python code) were applied to model and optimize biodiesel yield from extracted watermelon oilseed. Highest biodiesel yield of 93.41 wt% was obtained under the experimental conditions of 4min duration, 350 W microwave power, 4 wt% of catalyst, and MeOH/oil ratio of 8:1 based on Central Composite Design rotatable. The optimum value of the biodiesel yield from Machine Learning was 91.7 wt%, showing a marginal performance over the Central Composite Design rotatable value (91.6 wt%) at the optimized conditions of 3 min, 280 W, 3 wt% catalyst loading and MeOH/oil molar ratio of 6:1. The correlation of the coefficient (R2) of the model was 0.9827 for Central Composite Design rotatable while the R2 of the Machine Learning model was 1.0. Thus, python coding in terms of prediction and accuracy of biodiesel yield was superior to Central Composite Design rotatable, even though both models provide a reliable response within the region of data analyzed. The Gas Chromatography-Mass Spectroscopy of the biodiesel produced revealed the presence of both saturated and unsaturated fatty acid methyl esters. Biodiesel properties from watermelon seed oil transesterification fall within the recommended standard for biodiesel fuel. This study concluded that an effective green biowaste catalyst generated from earthen waste could enhance biodiesel production from watermelon seed oil, hence, ensuring sustainability and economic feasibility for biodiesel industries.

Polyoxovanadate Catalyzed Synthesis of Biodiesel (Methyl Esters) from Waste Cooking Oil

Depleting fossil fuel resources and the steady increase in energy consumption have spurred research interest in alternative and renewable energy sources. This study aimed to investigate the transesterification of waste cooking oil using Polyoxovanadate (POV) as a catalyst. The waste cooking oil was first acquired and subjected to physicochemical analysis for characterization purposes. Subsequently, transesterification of the oil with methanol was performed using Polyoxovanadate (POV) synthesized from Ammonium metavanadate (NH4VO3) solution at pH. The synthesized POV underwent characterization using techniques including UV-visible spectrometry, Fourier transform infrared (FTIR) spectrophotometry, X-ray Diffraction (XRD), and Scanning Electron Microscopy (SEM). The resulting biodiesel was also characterized using FTIR, Gas Chromatography-Mass Spectrometry (GC-MS), and its fuel properties were determined using ASTM Methods. The process proved successful, resulting in a biodiesel yield of 76.44 % when employing a catalyst loading of 0.8 g, a 1:9 oil-to-methanol ratio, and conducting the reaction at 60 °C for 90 minutes. The biodiesel obtained predominantly consisted of saturated fatty acid methyl esters. Furthermore, biodiesel exhibited favorable fuel properties that met the standards established by ASTM for diesel engines. Notably. Its low sulfur content highlighted its environmentally friendly nature in comparison to petroleum diesel.

Advancement of biodiesel fuel quality and NOx emission control techniques

Sustainable waste derived biodiesel can substitute significant amount of fossil-based fuels currently used for marine propulsion, agricultural processes, small scale power generation, and in heavy goods vehicles. However, biodiesel fuel quality varies depending on the feedstock type, production method and storage conditions. Meeting biodiesel standards and reduction of NOx emissions are two main challenges when biodiesels are being used in the internal combustion engines. This study aims to address these two challenges by using biodiesel-biodiesel blending and various NOx reduction techniques. Biodiesels produced from waste resources and inedible plant seed oils are investigated. Fuel properties, biodiesels standards, and engine test results are reviewed. It was found that blends of animal fat biodiesels and vegetable oil biodiesels are likely to improve fuel properties and combustion characteristics. The biodiesel-biodiesel blends also help to reduce exhaust pollutants. The saturation level of the biodiesel fuel is increased through this technique. Animal fat biodiesels are composed of saturated fatty acid methyl esters, and vegetable oil biodiesels are composed of unsaturated fatty acids. The NOx gas emission reduction techniques are investigated and categorised under three sub-groups, fuel treatment, engine adjustment and exhaust after-treatment. Based on the state of art review, scopes for future R&D topics are presented for researchers and relevant industries.

Low-temperature thermal pre-treated sewage sludge for feeding of black soldier fly (Hermetia illucens) larvae: Protein, lipid and biodiesel profile and characterization

Previous work showed that low-temperature thermal pre-treatment of waste activated sludge (WAS) under different temperatures (30, 60, 75, 90 °C) and durations (2, 4, 8, 16 h) prior to black soldier fly larvae (BSFL) rearing could improve the larval growth. In this work, the biochemical profiles of WAS-fed BSFL and the characteristics of biodiesel produced were reported. The BSFL fed with pre-treated WAS had high protein contents (44%–54%) and moderate lipid contents (21%–25%). The WAS pre-treated at 90 °C for 16 h produced BSFL with the highest protein and lipid yields, achieving 69% and 71% of increments, respectively, as compared with the controlled WAS. Subsequently, high conversion of lipid into biodiesel (>90%) could be achieved through the acid-catalyzed transesterification process. The BSFL biodiesel was dominated by saturated fatty acid methyl esters (FAME), with C12:0 being the abundance. This unique FAME profile enabled BSFL biodiesel to have low iodine value, high cetane number and more oxidatively stable as compared with other reported biodiesels like palm oil and rapeseed oil biodiesels. The BSFL biodiesel also satiated the biodiesel standards of EN 14214 and ASTM D6751, except for the flash point, which was still higher and safer than petroleum diesel. In short, the thermal pre-treatment of WAS was effective in promoting BSFL growth and its lipid yield, ultimately leading to higher biodiesel production.

Physicochemical and aging characterisation of bio-binders from pine wood resin for paving applications

This study characterised two bio-binders (named Bio A and Bio B) derived from pine wood resins and designed for full replacement of asphalt binder. Bio A and Bio B were compared to a petroleum-based asphalt binder (AC 30/45). Elemental analysis, Fourier-Transform Infrared Spectroscopy, Gas Chromatography-Mass Spectrometry, Thermogravimetric analysis, and Linear Viscoelastic characterisation were applied to evaluate the materials studied. The susceptibility to aging was evaluated by comparing unaged and short-term aged samples of the three binders. Bio A showed a penetration grade of 29 (0.1 mm) and softening point of 55.2°C, while Bio B showed 21 (0.1 mm) and 57°C, respectively. AC 30/45 showed a penetration grade of 30 (0.1 mm) and softening point of 55°C. Bio B was found as more prone to aging than Bio A and AC30/45. This result might be related to the higher presence of saturated fatty acid methyl esters in Bio B.

Efficient rapid fractionation of fatty acid methyl esters (FAMEs) through evaporative urea inclusion

FAMEs work as an alternative to petroleum-based diesel fuels for its low carbon footprint. However, FAMEs' qualities are constrained by the sources' fatty acid profiles. Fractionation of FAMEs can significantly change biodiesel's qualities. Compared to other fractionation methods, evaporative urea inclusion fractionation can rapidly and effectively separate the saturated FAMEs. In addition, FTIR analysis indicated the possible conjugation of host structures by unstable hydrogen bonding and oxygen bonding. Crystallite sizes and strain of urea inclusion compounds (UICs) were calculated from the XRD spectrum, influenced by FAMEs' structures and operation processes. Only the ratios of urea to FAMEs can significantly affect compositions in evaporative urea inclusion fractionation. However, UICs formation rates were influenced by all operation conditions, such as temperatures, pressures, and ratios of urea to FAMEs to solvent. The products were evaluated by the low-temperature performance, cetane number, oxidation stability, energy density, and emissions. Urea inclusion fractionation can significantly improve the low-temperature performance, the major constraint for enlarging the utilization. However, the decreased cetane number and oxidation stability indicated the possible need for antioxidants and cetane improvers after urea inclusion fractionation. Moreover, the unsaturated enriched products from urea inclusion fractionation can provide the feedstock to synthesize biochemical or biomaterials, such as carboxylic acids, polyesters, and biolubricants.

Synergistic effect in co-processing a residue from a transesterification process with vacuum gas oil in fluid catalytic cracking

• Co-processing of bio-oil in existing fluid catalytic cracking unit produces biofuel. • Bio-oil oxygen content determines its blends level with vacuum gas oil or VGO. • Distillation residue from biodiesel production using waste fats and oil is used. • Synergistic effect of bio-oil and VGO shows yield of gasoline higher than predicted. • Cracking of 10 wt% bio-oil has the closest coke characteristics compared to VGO. The catalytic co-processing of bottom fuel oil (BFO) with refinery vacuum gas oil (VGO) using a commercial fluid catalytic cracking (FCC) zeolite equilibrium catalyst was carried out to ascertain its potential as a source for biofuels. The BFO used was the distillation residue from biodiesel transesterification process using waste fats and oil; being a mixture of saturated and unsaturated fatty acid methyl esters. The catalytic cracking experiments were performed in a laboratory fixed bed micro activity test (MAT) reactor at 516 °C and atmospheric pressure. As well as the VGO and BFO, three different blends were used with BFO to VGO mass ratios of 10:90, 20:80 and 50:50, and catalyst-to-oil (C/O) ratios of 3.0 – 5.7. The synergistic effect of BFO in VGO blends includes the yield of gasoline, and LPG being higher than predicted for the blends of 10 wt% BFO in VGO. Also, the formation of more CO 2 with the increase in BFO blend level suggests CO 2 production through decarboxylation reactions as a possible route. The compositions of the produced gasoline for pure VGO and 10 wt% BFO are similar as well. The cracking of 10 wt% BFO gives a higher fraction of aromatics, alkenes and naphthenes than other blends. However, some deterioration was observed when higher substitution levels of BFO were used, resulting in a decrease in the gasoline yield and higher yields of LCO, HCO and coke as predicted. Overall, co-processing BFO with VGO may be economically attractive because the BFO is obtained from waste oils and fats which are one of the under-exploited sources of biodiesel feedstocks and add value to waste management.

Measurements of soot and response optimisation of laminar pool and prevaporised jet flames for various oxygenated biofuels

In this study, the generation of soot from the combustion of biodiesels and their blend with fossil diesel are investigated under laminar pool flame and prevaporised diffusion jet flame conditions. Neat biodiesels from eight feedstocks including carotene palm, palm, soy, coconut, rice bran, waste vegetable oil, duck, and goose, alongside two methyl esters of methyl laureate and methyl myristate are blended with fossil diesel at 20% volumetric intervals to form 51 different blends. The soot volume fractions for the combustion of all blends are determined using continuous-wave laser cavity extinction (CW-LCE) calibrated 2D laser-induced incandescence (2D-LII) technique. Results show that biodiesels with higher degree of saturation produce less soot, as reflected in both laminar pool and prevaroprised diffusion jet flames. The experimental data is further analysed using design of experiments (DOE) methodology. The mixture design model (MDM) following the simplex design is used to focus on the soot generating effects arising from the chemical compositions by classifying the chemical components into hydrocarbons and saturated, monounsaturated and polyunsaturated fatty acid methyl esters (FAME). The results from the Cox response trace plot associated with DOE elucidate the effects of the individual chemical group within the fuels. Both laminar flame types for the all 51 biodiesel-diesel blends exhibit the same trends with differing magnitudes. Saturated FAME has the largest singular effect on soot generation followed by hydrocarbons. However, when only neat biodiesels are considered, the laminar pool flame and laminar diffusion jet flames show differing trends for all the chemical groups. Monounsaturated FAME and saturated FAME have the greatest influence on neat biodiesel-generated soot for laminar pool flame and laminar diffusion jet flame, respectively. From the mixture design model, an optimum synthetic biodiesel mixture containing 16.1%, 34.6% and 49.3% of saturated, monounsaturated and polyunsaturated methyl esters is recommended for the lowest soot generation.

Attached microalgae converting spent coffee ground into lipid for biodiesel production and sequestering atmospheric CO2 simultaneously

The impacts of simultaneous exposures of arbitrary light intensities and photoperiods on attached Chlorella vulgaris microalgal growth onto spent coffee ground (SCG) were studied, and subsequently optimized using Response Surface Methodology (RSM) tool. The statistical analysis revealed the optimum light intensity and photoperiod were achieved at 100 μmol/m2s and 20:4 dark:light hours/cycle, respectively, producing microalgal density of 0.358 g/g and lipid productivity of 16.8 mg/Lday. The biodiesel yielded from the optimum condition possessed high cetane number and oxidative stability due to the high saturated fatty acid methyl esters (FAME) content of 63.7 %. In fact, the major FAME compositions ranged within C16 to C18 which were favourable for quality biodiesel production. Furthermore, the viability of SCG to serve as a carbon source was also evidenced by the high productivities of microalgal protein and carbohydrate at 94 and 168 mg/L day, respectively. The capability of attached microalgal cultivation in sequestering atmospheric CO2 was finally unveiled, with high CO2 capture rate being recorded at 9.38 mg/L h. Accordingly, growing attached microalgae onto SCG was recognized as an alternative approach for sustainable CO2 reduction, while producing green diesel to assuage the global warming phenomenon.

Fractionation of fatty acid methyl esters via urea inclusion and its application to improve the low-temperature performance of biodiesel

Biodiesel is viewed as the alternative to petroleum diesel, but its poor low-temperature performance constrains its utilization. Cloud point (CP), the onset temperature of thermal crystallization, appropriately shows the low-temperature performance. The effective way to reduce CP is to remove saturated fatty acid methyl esters (FAMEs). Compared to current methods, this work describes an extraordinary approach to fractionating FAMEs by forming solid urea inclusion compounds (UICs). Urea inclusion fractionation reduces the CPs by removing high melting-point linear saturated FAME components. Urea inclusion fractionation in this study was performed under various processing conditions: mass ratios of urea to FAMEs and solvents to FAMEs, various solvents, FAMEs from various feedstocks, and processing temperatures. Supersaturation of urea in the solution is the driving force, and it significantly affects yield, composition, CP, separation efficiency, and selectivity. Through a single urea inclusion fractionation process, FAMEs, except palm oil FAMEs, resulted in CP reduction ranging from 20 to 42 oC with a yield of 77–80% depending on the compositions. CP of palm oil FAMEs could reach as low as -17 oC with a yield of 46% after twice urea inclusion fractionation. According to the model prediction, the cetane number after urea inclusion fractionation decreased about 0.7–2 but was still higher than the minimum biodiesel requirement. Oxidation stability after urea inclusion decreased according to the proposed model, but this can be mitigated by adding antioxidants. Emission evaluation after urea inclusion fractionation indicated decreased hydrocarbons, carbon monoxide, and particulate matter. However, it resulted in the increasing emission of nitrogen oxides.

Thermodynamically predicting liquid/solid phase change of long-chain fatty acid methyl esters (FAMEs) and its application in evaluating the low-temperature performance of biodiesel

BackgroundLong-chain FAMEs, also called biodiesel, are viewed as the alternative to petroleum diesel for renewability and sustainability. Because the fatty acid profiles significantly varied for the sources, the compositions significantly affected the biodiesel properties, such as cloud points. The cloud point of biodiesel indicates the phenomenon of solid-liquid phase change. Previous models for cloud point predictions were limited to known components in the mixtures. MethodsThe cloud points of the binary, ternary and multicomponent mixtures of fatty acid methyl esters were measured in this study. A cloud point prediction model was established based on phase equilibrium with the modified Universal functional activity coefficient (UNIFAC) model and excess fusion enthalpy for predicting the nonideal behaviors of the components resulting from the molecular shape and molecule interactions. Significant findingsThe developed thermodynamic model accurately predicts the cloud point according to compositions. The model extends the application scope to the low-temperature range. There had eutectic points in the phase diagrams when the mixtures consisted of either saturated FAMEs or unsaturated FAMEs. This study proved that saturated FAMEs regulate the cloud points, but unsaturated FAMEs affect them through group interactions. Moreover, the proposed model can predict unknown FAMEs mixture as it is built on the group contributions.

Flow and crystallization of saturated fatty acid methyl esters and their binary mixtures

AbstractDemand for biodiesel has increased due to being a more environmentally‐friendly fuel. Cold weather operation of biodiesel is challenging due to fatty acid methyl ester (FAME) content in biodiesel. Saturated FAMEs crystallize at relatively high temperatures, increase the viscosity of biodiesel, and can clog fuel lines. Here, several factors altered crystallization temperature (CT) of FAMEs, including composition, shear rate, and cooling rate. The crystallization of pure and binary mixtures of methyl palmitate, methyl myristate, and methyl stearate were studied under shear flow and static conditions. Static phase CTs of pure methyl palmitate, methyl myristate, and methyl stearate were 26, 14, and 35°C, respectively. In binary mixtures, CTs were depressed up to 7°C, which agreed with freezing point depression theory. Increasing shear rate up to 100 s−1 decreased CT by 2°C compared to static conditions. Decreasing cooling rate from 1 to 0.1°C/min increased CT less than 2°C. Overall, FAME composition altered CT more than shear flow or cooling rate for pure and binary mixtures of three FAMEs.

NITROGEN STARVATION INDUCED LIPID ACCUMULATION BY Chlorococcum infusionum (EAU-10) AS POTENTIAL RENEWABLE SOURCE OF LIPID FOR BIODIESEL PRODUCTION

Microalgae are organisms effective of accumulating high quantity of industrially important lipids with promising characteristics as an excellent feedstock for biodiesel production. This study assess the possibility of using a green microalga, Chlorococcum infusionum (EAU-10) for biodiesel production by evaluating the growth characteristic, lipid yield and fatty acid profile of the microalga cultivated at varying concentrations of nitrogen source (0.375 - 1.50 g L-1 NaNO3). High lipid accumulation was observed in nitrogen-starved cultivation condition (0.375 g L-1 NaNO3) after 23 days of growth. Maximum biomass concentration of Chlorococcum infusionum (EAU-10) under nitrogen starved condition is 0.577 ± 0.003 g L−1 with 21.26% oil content per dry weight of algal biomass and lipid productivity of 22.08 mg L−1 day−1. Nitrogen starvation caused an increase in the total oil content and a decrease in biomass production of the microalga. Profiling of fatty acids of the obtained algal biodiesel shows methyl palmitate (C16:0) and methyl nonadecanoate (C19:0) contribute to almost 70% of Chlorococcum infusionum (EAU-10) fatty acid methyl esters (FAME) profile. Overall, a total of 74.58% of saturated fatty acid (SAFA) methyl ester content is present in the algal lipid, which is exceedingly high in contrast to other similar studies. Analysis of C. infusionum FAME profile in relation to some important fuel properties showed that the algal oil has the potential to produce biodiesel with excellent fuel qualities.

Effect of Thermal Treatment and Nickel-Salt Modification on the Catalytic Performance of the Illite-Kaolinite Clay from Bukittinggi of West Sumatra in Palm Oil Transesterification

The effect of thermal and chemical modification on the catalytic performance of illite-kaolinite clay (obtained from Bukittinggi, West Sumatra) in the transesterification of palm oil was investigated. Characterization with XRD, XRF and FTIR indicated a slight change in the composition of the crystal phase and the Si/Al molar ratio after such clay was calcined at 450 °C. XRF measurements also confirm that after treatment with two nickel salts, the natural clay absorbs more nickel sulfate than nitrate, while temperature played an important role in increasing the performance of the clay in loading nickel about 2 times bigger at a higher temperature. All clay-based materials prepared in this study were tested for their catalytic activity and selectivity in the transesterification of palm oil to produce Fatty Acid Methyl Ester (FAME) using the previously reported procedure. Chemical modification of clay samples with nickel sulfate and nickel nitrate was found to increase the catalytic performance of the clay in producing FAME from 38 to about 60 % while thermally treated at 450 °C yielded slightly higher to about 67 %. In terms of selectivity, all clay-based catalysts in this study gave almost the same amount of saturated and unsaturated FAME