High Quality Biodiesel Production Research Articles

Transesterification reaction time impacts on oxidation stability and acid number of biodiesel production from waste cooking oil

The scarcity of fossil fuels, environmental concerns, and the sharp rise in fossil fuel prices have driven scientists to search for alternative fuels. The characteristics of biodiesel have made the quest for high-quality biodiesel production particularly appealing. The use of waste cooking oil is a key component in reducing biodiesel production costs by 60-90%. Researchers have employed various types of transesterification reactions with both homogeneous and heterogeneous catalysts for biodiesel production; in this study, a 0.5% NaOH catalyst is used. The objectives of this study are to produce biodiesel fuel based on waste cooking oil, evaluate the impact of reaction time variation on the oxidation value and acid value of biodiesel produced from waste cooking oil, and statistically test the effects of reaction time on the oxidation value and acid value of biodiesel produced from waste cooking oil using analysis of variance (ANOVA). The optimum yield was obtained at a reaction time of 90 minutes, achieving 97%. The results for acid number and oxidation value for various reaction times complied with ASTM, EN, and SNI standards. Linear regression analysis of ANOVA for the acid number concluded that the P-value t3 is 0.399, which is greater than Alpha = 0.05, indicating that the variation in reaction time does not have a significant effect on the acid number. Linear regression analysis of ANOVA for the oxidation number concluded that the P-value t3 is less than Alpha (0.047 < 0.05), indicating that reaction time has a significant effect on the oxidation number.

WITHDRAWN: rGO@CaO/NiO as a bifunctional heterogeneous nanocatalyst for high-quality biodiesel production from degraded waste oil by microwave-assisted: Diesel engine parameters assessment

In this research, a highly effective rGO@CaO/NiO bifunctional nanocatalyst was synthesized and utilized for the generation of biodiesel from degraded waste oil (DWO) through microwave assistance. A comprehensive analysis was conducted to assess the catalyst structure, revealing a notable specific surface area with significant surface characteristics for the rGO@CaO/NiO bifunctional nanocatalyst. The maximum biodiesel yield was achieved 97.46% under optimum conditions including methanol to oil ratio of 11.1 mol/mol, catalyst content of 3 wt.%, microwave time of 7.5 min, and stirring speed of 700 rpm. The catalyst's reusability was demonstrated through multiple cycles, maintaining high stability and consistent biodiesel yield over seven iterations. The activation energy and exponential factor for the conversion of DWO to biodiesel were determined as 30.91 kJ/mol and 2.3×104 min-1, respectively. The physical attributes of DWO-derived biodiesel revealed that they fall within the ASTM D6751 standard range. The impact of adding biodiesel to petrodiesel/biodiesel blends at various torques on the emission of key pollutants (CO, NOx, CO2, and UHC) and engine performance (BP, EGT, BTE, and BSFC) was investigated, yielding promising results. The rGO@CaO/NiO appears as a superior choice for biodiesel production, offering exceptional reusability, and significant biodiesel efficiency achieved within a short reaction time.

Physicochemical exploration of castor seed oil for high-quality biodiesel production and its sustainable application in agricultural diesel engines

In Thailand, castor seeds often classified as weeds are locally distributed in every region of the country and not fully utilized. Therefore, this research aimed to study the physicochemical properties of castor seed oil as a raw material for the production of liquid biofuels. The study of extracting oil from castor seeds using various methods revealed that the Soxhlet extraction technique, a circulatory extraction method, yielded the highest amount of extracted oil at 52.45 wt%, compared to the dry weight of the castor seed. In the study of the physicochemical properties of castor seed oil, the results revealed that the major components were 89.71% ricinoleic acid, 3.96% linoleic acid, and 3.09% oleic acid, respectively. The kinematic viscosity of castor seed oil was as high as 164.68 cSt. However, when converted into castor seed oil biodiesel, the kinematic viscosity decreased to 10.36 cSt, still two times higher than that of the standard biodiesel oil. Therefore, blending castor seed oil biodiesel with petroleum diesel oil to obtain B30 and B40 revealed that the fuel properties met the qualifications of both ASTM D6751 and EN 14214 standards. The initial tests on agricultural diesel engines found that the gas emissions of CO2, CO, HC, and NO2 from biodiesel blends B30 and B40 tend to be lower than those from using only petroleum diesel oil and biodiesel oil derived from castor seeds. Therefore, blending biodiesel oils B30 and B40, derived from castor seed oil, not only results in good biofuel liquid qualities but also proves to be efficient for use in agricultural diesel engines. It is suitable to encourage the community to adopt it for agricultural purposes in the future.

Optimization of methyl ester synthesis using gas/liquid phase pulsed discharge plasma in a novel oscillatory slug flow reactor

In the present research, an innovative oscillatory slug flow reactor (OSFR) under the treatment of gas–liquid phase pulsed discharge plasma was developed for biodiesel production. The main goal was continuous production of high quality biodiesel at low temperature and pressure. Experimental tests were carried out under the influence of four main operating parameters including applied voltage, molar ratio, reactant flow rate, and catalyst concentration. The response surface method was employed to optimize experimental tests. The results showed that the proposed technology provided 94% production efficiency under the optimal conditions of voltage 19.4 kV, molar ratio 6.4, flow rate 2.7 ml/s, and catalyst 0.9 wt. %. According to the statistical analysis, increasing the applied voltage and reducing the flow rate have a strong effect on the Fatty Acid Methyl Ester yield, while the concentration of potassium hydroxide and methanol have less effect on the overall efficiency. In addition, the characteristics of the produced biodiesel were in accordance with ASTM D6751 standards. Surprisingly, the optimal energy consumption in this system was 95 kJ/l, which is more economically viable. In general, this study showed that the combined system of gas/liquid phase plasma in the OSFR reactor has a high synergistic potential for the transesterification reaction.

Coupling anaerobic co-digestion of winery waste and waste activated sludge with a microalgae process: Optimization of a semi-continuous system

Wine production represents one of the most important agro-industrial sectors in Italy. Wine lees are the most significant waste in the winery industry and have high disposal and storage costs and few applications within the circular economy. In this study, anaerobic digestion and a microalgae coupled process was studied in order to treat wine lees and waste activated sludge produced within the same facility, with the aim of producing energy and valuable microalgae biomass that could be processed to recover biofuel or biostimulant. Chlorella vulgaris was cultivated on liquid digestate in a semi-continuous system without biomass recirculation. The best growth and phytoremediation performance were achieved applying a hydraulic retention time (HRT) of 20 days with a stable dry weight, lipid and protein storage of 1.85 ± 0.02 g l−1, 33.48 ± 7.54 % and 57.85 ± 10.14 % respectively. Lipid characterization highlighted the potential use in high quality biodiesel production, according to EN14214 (<12 % v/v linolenic acid). The microalgae reactor’s liquid output showed high removal of ammonia (95.72 ± 2.10 %), but low organic soluble matter reduction. Further semi-continuous process optimization was carried out by increasing the time between digestate feeding and biomass recovery at HRT 10. These operative changes avoided biomass wash-out and provided a stable phytoremediation of the digestate with 84.58 ± 4.02 % ammonia removal, 33.01 ± 1.44 % sCOD removal, 38.06 ± 2.65 % of polyphenols removal.

Cattle wastewater treatment using green microalga Coelastrella sp. KNUA068 as a promising bioenergy feedstock with enhanced biodiesel quality.

Global water scarcity increased the demand for clean water, leading to attention on microalgae-based biological treatment for wastewater due to economic feasibility and sustainable biomass applications. This study isolated indigenous microalga Coelastrella sp. KNUA068 from a wastewater treatment plant, observed its admissible growth rate in diluted cattle wastewater (DCW), and used it for wastewater treatment analysis. The microalga showed high growth rates in indoor and outdoor cultivation with 100% DCW. In addition, the ammonia nitrogen and nitrate nitrogen removal rates of the microalga were 69.97 and 60.35%, respectively, in indoor cultivation, and 50.63 and 67.20%, respectively, in outdoor cultivation. Carotenoid content analysis revealed lutein as the highest productivity carotenoid, and zeaxanthin production was higher in outdoor cultivation. The biomass exhibited suitable biodiesel quality with a cetane number of 50.8 for high-quality biodiesel production. Coelastrella sp. KNUA068 demonstrates potential for bioenergy feedstock, carotenoid production, and wastewater treatment.

Biodiesel production from spirulina algae oil over cobalt microsphere through esterification reaction

This study displays the production and conformance of cobalt microsphere as a catalyst in the esterification reaction for biodiesel production from spirulina algae oil. The porous microsphere was successfully synthesized via a simple solvothermal method and evaluated using EDX, XRD, FE-SEM, TGA, CO2-TPD, and BET. The resulting microsphere cobalt has a surface area of 150.83 m2/g and a total pore volume of 35.33 cm3/g. The optimal reaction conditions for the esterification of spirulina algae oil over the cobalt microsphere were: 60 °C, a molar ratio of 7:1 for methanol: spirulina algae oil, and 240 min to achieve 95 % yield of corresponding product. Also, biodiesel samples comply with the ASTM standards. The chemical composition of spirulina oil was analyzed by GC-Mass analysis. The cobalt microsphere offers various benefits such as stability (chemical/physical), simple catalyst separation, and the production of high-quality biodiesel.

Production of high quality biodiesel from sunflower soapstock acid oil as novel feedstock: Catalyzed by immobilized pancreatic lipase

AbstractEdible refined oils, which are utilized as raw materials in biodiesel production, have been replaced by by‐products (acid oil, fatty acid, deodorized distillate, and soapstock distillates) obtained from the vegetable oil refining industry, in recent years. This study aims to investigate the production of high quality biodiesel fuel in accordance with the standards (TS EN and ASTM) from sunflower soapstock acid oil. This feedstock was donated by an oil factory in the Thrace region, Turkey. Esterification reaction was performed by immobilized enzyme. For this, immobilization was carried out by covalent binding of pancreatic lipase in glutaraldehyde activated chitosan and optimum immobilization conditions were determined. The activity of the immobilized lipase and the retained activity were found to be 65.69 U/μg and 61.8%, respectively (pH: 7.5, 37°C). The Km (Michealis constant) and Vmax (maximum velocity of an enzymatically catalyzed reaction) values of the immobilized enzyme were found to be 5.1 mmol/L and 48.6 U/min/mg protein, respectively. The immobilized enzyme was employed as a biocatalyst for esterification of sunflower soapstock acid oil. Notably, an impressive yield of 75.6% was attained under the conditions of a 1:5 molar ratio of soapstock acid oil to methanol, with 10 wt% immobilized lipase as the catalyst, and a reaction temperature of 45°C for 36 h. The resulting biodiesel exhibits fuel characteristics that meet the standards outlined in TS EN 14214:2012 + A2 and ASTM D6751‐02.

Chromatographic assessment of biodiesel production from Peganum harmala seed oil using environmentally benign nano-catalysts.

This work gives a comprehensive chromatographic assessment of biodiesel generation from plant seed oil using ecologically friendly nano-catalysts. Researchers all over the world are actively looking for new ways to satisfy the urgent need for clean and renewable energy sources. The resultant biodiesel was fully characterized utilizing modern techniques like scanning electron microscopy, energy diffraction X-ray and X-ray diffraction. The biodiesel gas chromatography/mass spectrometry analysis revealed four significant peaks of fatty acid methyl esters, indicating high-quality biodiesel production. Furthermore, the biodiesel fuel qualities were discovered to be comparable with international standards such as ASTM D-6571 and EN-14214. This indicates that the iron-modified clay nano-catalyst can be used as a catalyst for large-scale biodiesel production. This work is important because it could lead to the large-scale production of a novel, non-food feedstock. We may lessen our reliance on fossil fuels and contribute to a more sustainable and ecologically friendly energy future by leveraging the usage of biodiesel produced in this way. The chromatographic assessment of biodiesel production from non-edible seed oil using environmentally benign nano-catalysts holds significant promise in advancing sustainable and eco-friendly biodiesel production methods, contributing to a cleaner and more environmentally responsible energy sector.

Appraising the phycoremediation potential of cyanobacterial strains Phormidium and Oscillatoria for nutrient removal from textile wastewater (TWW) and synchronized biodiesel production from TWW-tolerant biomass

In this study, phycoremediation of textile wastewater (TWW) by freshwater cyanobacterial strains such as sp., Oscillatoria sp. F01 and Oscillatoria sp. F02 was evaluated, and lipids were simultaneously extracted from biomass for biodiesel production. Onset of the study, Phormidium sp. and Oscillatoria sp. F01 has better growth rates, increased biomass production, high chlorophyll content, and efficient nutrient utilization in TWW compared to Oscillatoria sp. F02. Phormidium sp. showed 1.41 g/L dry weight, followed by Oscillatoria sp. F01 with 1.39 g/L and Oscillatoria sp. F02 with 1.02 g/L biomass. Both strains demonstrated their capability to elevate the pH level while reducing TDS and eliminating/reducing several nutrients such as nitrates, nitrites, phosphates, sulphates, sulphides, chlorides, calcium, sodium, and magnesium. Further, the total lipids extracted from the TWW-grown Phormidium sp., Oscillatoria sp. F01 and Oscillatoria sp. F02 was estimated to be 8.20, 13.70 and 11.20 %, respectively, on day 21, which was higher than the lipid content obtained from control cultures. Further, biodiesel produced from the lipids of all strains showed higher levels of C12:0, C16:0, C16:1, C18:1, C18:2, and C18:3 among all the fatty acids. Therefore, they can potentially offer a valuable source of lipids and diverse fatty acids for high-quality biodiesel production. This integrated system not only offers a solution for TWW treatment but also provides a feedstock for renewable fuel production simultaneously.

Biodiesel production from mahua oil: characterisation, optimisation, and modelling with a hybrid statistical approach

Present study investigates the feasibility of utilising mahua oil as a feedstock for the production of high-quality biodiesel via the transesterification process. Mahua fruit kernels offer an excellent biodiesel source, with an oil content of approximately 35–40%. This study employs a hybrid statistical approach, combining Response Surface Methodology (RSM) and Genetic Algorithm (GA), to optimise the transesterification process. Through the execution of L31 pre-designed experiments, this work analyzes the significance of four key process parameters: methanol-to-oil ratio, catalyst concentration, reaction temperature, and reaction time. The collective influence of these parameters on biodiesel production is comprehensively examined. The GA-derived optimal conditions for biodiesel production are determined as a molar ratio of 7.28 with a 0.93 wt.% catalyst concentration, a reaction temperature of 59.43°C, and a reaction time of 113.62 min. Experimental results validate the model predictions, as the actual yield of Mahua biodiesel reaches 97.54%, with a deviation of only 2.82% from the predicted value. Furthermore, the fuel characteristics of Mahua methyl ester were assessed and compared to ASTM standards. In conclusion, this study highlights the potential of Mahua oil as a valuable and cost-effective feedstock for biodiesel production, thereby opening avenues for its future application as an alternative fuel source.

Removal of zinc by Selenastrum sp. and simultaneous biodiesel production from metal-resistant biomass for energy and environmental sustainability

In this study, the phycoremediation of zinc by the unicellular green alga, Selenastrum sp. and simultaneous biodiesel production from heavy metal resistant biomass was investigated. The microalga Selenastrum sp. was used to remove the zinc amended at 1, 3, 5, 7 ppm in the BG II medium. In all the tested zinc concentrations (1–7 ppm), there was no noticeable heavy metal stress on the microalga and the algal culture showed a steady and better growth pattern in zinc amended medium than that control (no zinc added). Furthermore, on the 24th day, the biomass concentration was 1.63 g/L for the 5 ppm and 7 ppm zinc dosed experiments, which was higher than the control. Atomic adsorption spectroscopic analysis showed that zinc concentration in the medium (5 and 7 ppm) was reduced to ~0.44 ppm, which is equivalent to 90 % heavy metal removal efficiency. The total lipid content and biodiesel yield from zinc-resistant Selenastrum biomass was 17.6 and 65.1 %, respectively. Finally, test microalga grown in zinc-added media produced beneficial fatty acids such as palmitic, palmitoleic, oleic, stearic, linoleic, and linolenic acid for high-quality biodiesel production.

Determination of superior Pistacia chinensis accession with high-quality seed oil and biodiesel production and revelation of LEC1/WRI1-mediated high oil accumulative mechanism for better developing woody biodiesel

BackgroundBased on our previous studied on different provenances of Pistacia chinensis, some accessions with high quality and quantity of seed oils has emerged as novel source of biodiesel. To better develop P. chinensis seed oils as woody biodiesel, a concurrent exploration of oil content, FA profile, biodiesel yield, and fuel properties was conducted on the seeds from 5 plus germplasms to determine superior genotype for ideal biodiesel production. Another vital challenge is to unravel mechanism that govern the differences in oil content and FA profile of P. chinensis seeds across different accessions. FA biosynthesis and oil accumulation of oil plants are known to be highly controlled by the transcription factors. An integrated analysis of our recent transcriptome data, qRT-PCR detection and functional identification was performed as an attempt to highlight LEC1/WRI1-mediated transcription regulatory mechanism for high-quality oil accumulation in P. chinensis seeds.ResultsTo select ideal germplasm and unravel high oil accumulative mechanism for developing P. chinensis seed oils as biodiesel, five plus trees (accession PC-BJ/PC-AH/PC-SX/PC-HN/PC-HB) with high-yield seeds were selected to assess the variabilities in weight, oil content, FA profile, biodiesel yield and fuel property, revealing a variation in the levels of seed oil (50.76–60.88%), monounsaturated FA (42.80–70.72%) and polyunsaturated FA (18.78–43.35%), and biodiesel yield (84.98–98.15%) across different accessions. PC-HN had a maximum values of seed weight (26.23 mg), oil (60.88%) and biodiesel yield (98.15%), and ideal proportions of C18:1 (69.94%), C18:2 (17.65%) and C18:3 (1.13%), implying that seed oils of accession PC-HN was the most suitable for ideal biodiesel production. To highlight molecular mechanism that govern such differences in oil content and FA profile of different accessions, a combination of our recent transcriptome data, qRT-PCR detection and protein interaction analysis was performed to identify a pivotal role of LEC1/WRI1-mediated transcription regulatory network in high oil accumulation of P. chinensis seeds from different accessions. Notably, overexpression of PcWRI1 or PcLEC1 from P. chinensis seeds in Arabidopsis could facilitate seed development and upregulate several genes relevant for carbon flux allocation (plastidic glycolysis and acetyl-CoA generation), FA synthesis, TAG assembly and oil storage, causing an increase in seed oil content and monounsaturated FA level, destined for biodiesel fuel property improvement. Our findings may present strategies for better developing P. chinensis seed oils as biodiesel feedstock and bioengineering its high oil accumulation.ConclusionsThis is the first report on the cross-accessions assessments of P. chinensis seed oils to determine ideal accession for high-quality biodiesel production, and an effective combination of PcWRI1 or PcLEC1 overexpression, morphological assay, oil accumulation and qRT-PCR detection was applied to unravel a role of LEC1/WRI1-mediated regulatory network for oil accumulation in P. chinensis seeds, and to highlight the potential application of PcWRI1 or PcLEC1 for increasing oil production. Our finding may provide new strategies for developing biodiesel resource and molecular breeding.

Production of high-quality biodiesel through methanolysis of Bombyx mori pupae waste oil

ABSTRACT The inadequacy of natural resources to meet the energy demands of the population has led to new and sustainable ways of producing energy such as biodiesel. This study discusses the merits of employing desilked dried Bombyx mori pupae waste as feedstock for biodiesel production. This waste was found to have approximately 40% lipids, 54% proteins, and essential minerals in trace quantities. The maximum neutral lipid yield obtained through chemical extraction varied between 38% and 41% of the feedstock weight. This lipid was transesterified with an acid catalyst resulting in an approximate 90% yield of biodiesel. This product was characterized using GCMS, FTIR, and 1HNMR spectroscopy. These studies have indicated the presence of good-quality biodiesel. This biodiesel was also found to have an induction time of 7.06 hours at 110°C. The physicochemical properties of the produced biodiesel were tested according to standard testing methods and were found to be satisfactory. The produced biodiesel was compared with a commercial biodiesel for its properties, and was found to be superior. The energy value of the silkworm pupae biodiesel showed over 10% increase than commercial biodiesel. This process also doubles as an effective waste management practice for the sericulture industry.

Sustainable Biodiesel Production from a New Oleaginous Fungus, Aspergillus carneus Strain OQ275240: Biomass and Lipid Production Optimization Using Box–Behnken Design

Due to their low cost and ability to synthesize lipids for sustainable biodiesel production, oleaginous fungus has recently gained more prominence than other microorganisms. The new oleaginous fungus Aspergillus carneus OQ275240’s dry biomass, lipid content, and lipid yield were all optimized in this work, using the response surface methodology-based Box–Behnken design. Analysis of variance (ANOVA) was also used to examine the experimental data, and multiple regression analysis was used to fit the data to a second-order polynomial equation. Three independent variables, such as the concentration of yeast, glucose, and phosphorus, were examined for their mutual impacts. Maximum dry biomass (0.024 g/50 mL), lipid content (36.20%), and lipid yield (8.70 mg/50 mL) were achieved at optimal concentrations of 2.68 g/L of yeast, 20.82 g/L of glucose, and 0.10 g/L of phosphorus, respectively, showing that the actual data and predictions of the models were in good agreement. A. carneus OQ275240 has a favorable fatty acid profile that can be used to successfully create biodiesel, as shown by the presence of palmitic acid (C16:0), stearic acid (C18:0), and oleic acid (C18:1) in its fatty acid methyl esters (FAMEs) profile. Furthermore, the qualities of the biodiesel were investigated, and it was found that they fell within the parameters established by the international specifications EN 14214 (Europe) and ASTM D6751-08 (United States). These findings point to the newly evaluated filamentous fungal strain as a potential feedstock for the production of high-quality biodiesel.

Production and physicochemical properties of safflower seed oil extracted using different methods and its conversion to biodiesel

The production and physicochemical characterization of high quality biodiesel from the from safflower seed oil extracted by different extraction methods was studied. The oil extraction efficiencies of various extraction methods were compared. The hydraulic press, continuous pressing (expeller) and soxhlet extraction methods were used to extract oil from safflower seeds. The soxhlet extraction method was found to have the highest oil extraction efficiency up to 32.49%. The majority of fatty acid compositions of the safflower seed oil obtained were oleic acid (C18:1) and linoleic acid (C18:2) with 30.9% and 56.4%, respectively. In other words, it has been determined that the unsaturated fatty acids of safflower seeds oil constitutes more than 89% of total fatty acids. The synthesis of safflower seeds oil into a high quality biodiesel product was carried out by a one-step transesterification process catalyzed by an alcohol/oil molar ratio of 4.799/1 and KOH catalyst. The synthesis of biodiesel by transesterification process was confirmed by FT-IR, 1H NMR, 13C NMR spectroscopy and GC-FID chromatograms. Fatty acid methyl esters (FAME) in safflower seeds oil biodiesel were identified by GC-FID analysis. Majority of FAMEs were methyl hexadecanoate (C16:0), methyl octadecanoate (C18:0), methyl 9 octadecanoate (C18:1), methyl octadec-9-enoate (C18:1), methyl 9,12-octadecadienoate (C18:2) and methyl octadecatrienoate (C18:3). The percentage conversion of safflower seed triglycerides to the corresponding methyl esters determined by 1H NMR was calculated as 94.12%. In addition, various fuel properties of the synthesized biodiesel were determined using ASTM and EN standards and compared with relevant studies. The biodiesel product synthesized from safflower seed oil meets both ASTM-D6751 and EN-14214 standards. In conclusion, safflower seed oil is promising in terms of high productivity, quality and potential in the production of biodiesel products that can be used as a substitute for fossil-based diesel fuel.

Lipid production characteristics of a newly isolated microalga Asterarcys quadricellulare R-56 as biodiesel feedstock.

In this study, a new microalgal strain, Asterarcys quadricellulare R-56, was isolated for biomass and lipid production. The effects of carbon and nitrogen sources and initial pH on the cell growth and lipid accumulation of strain R-56 were investigated. At 10g L-1 glucose, 0.6g L-1 sodium nitrate, and pH 7, the highest biomass of 4.18g L-1 and lipid content of 43.66% were obtained. Microalgae had a broad pH tolerance in the range of 5-11, and the pH of the culture medium was close to neutral at the end of cultivation. The maximum contents of chlorophyll, carbohydrate, and protein under the recommended culture conditions were 19.47mgmL-1, 21.80%, and 29.94%, respectively. Palmitic and palmitoleic acid contents in strain R-56 accounted for as high as 83.73% of total fatty acids. This study suggested that strain R-56 was a promising lipid producer for high-quality biodiesel production.

Evaluation of oil accumulation and biodiesel property of Lindera glauca fruits among different germplasms and revelation of high oil producing mechanism for developing biodiesel

BackgroundLindera glauca with rich resource and fruit oil has emerged as novel source of biodiesel in China, but different germplasms show a variation for fruit oil content and FA profile. To develop L. glauca fruit oils as biodiesel, a concurrent exploration of oil content, FA composition, biodiesel yield, fuel property and prediction model construction was conducted on the fruits from 8 plus germplasms to select superior genotype for ideal biodiesel production. Another vital focus was to highlight mechanism that govern the differences in oil content and FA profile of different germplasms. The cross-accessions comparisons associated with oil-synthesized gene transcriptional level and oil accumulative amount led to the identification of potential determinants (enzymes, transporters or transcription factors) and regulatory mechanisms responsible for high-quality oil accumulation.ResultsTo select superior germplasm and unravel regulatory mechanism of high oil production for developing L. glauca fruit oils as biodiesel, 8 plus trees (accession LG01/02/03/04/05/06/07/08) with high-yield fruits were selected to evaluate the differences in oil content, FA profile, biodiesel yield and fuel property, and to construct fuel property prediction model, revealing a variation in the levels of fruit oil (45.12–60.95%), monounsaturated FA (52.43–78.46%) and polyunsaturated FA (17.69–38.73%), and biodiesel yield (80.12–98.71%) across different accessions. Of note, LG06 had a maximum yield of oil (60.95%) and biodiesel (98.71%), and ideal proportions of C18:1 (77.89%), C18:2 (14.16%) and C18:3 (1.55%), indicating that fruit oils from accession LG06 was the most suitable for high-quality biodiesel production. To highlight molecular mechanism that govern such differences in oil content and FA composition of different accessions, the quantitative relationship between oil-synthesized gene transcription and oil accumulative amount were conducted on different accessions to identify some vital determinants (enzymes, transporters or transcription factors) with a model of carbon metabolic regulatory for high-quality oil accumulation by an integrated analysis of our recent transcriptome data and qRT-PCR detection. Our findings may present strategies for developing L. glauca fruit oils as biodiesel feedstock and engineering its oil accumulation.ConclusionsThis is the first report on the cross-accessions evaluations of L. glauca fruit oils to determine ideal accession for producing ideal biodiesel, and the associations of oil accumulative amount with oil-synthesized gene transcription was performed to identify some crucial determinants (enzymes, transporters or transcription factors) with metabolic regulation model established for governing high oil production. Our finding may provide molecular basis for new strategies of developing biodiesel resource and engineering oil accumulation.

Direct production of isomerized biodiesel over MoS2/ZrPOx under solvent-free conditions

The catalytic deoxygenation and isomerization of biolipids in one pot is a challenge in the production of high-quality biodiesel. Herein, series of bifunctional catalysts, combining with in-situ sulfided MoO3 and phosphoric acid modified-ZrO2, were fabricated for upgrading of biolipid under solvent-free conditions. It is demonstrated that the bifunctional catalysts exhibit great performance for the hydrotreating of methyl palmitate and raw biolipid, affording up to 90% of total hydrocarbons with 20.3% and 18.7% of isomerized alkanes in diesel range. Among several studied ratios, the catalyst with Mo loading of 12.5% and P/Zr ratio of 1/7 achieves the highest yield of i-alkanes due to a coeffect of MoS2 and acid sites on the surface based on characterizations. The regenerated catalyst also shows excellent performance with no significant change in the structure. Moreover, a synergy between MoS2 and phosphoric acid is discussed to elucidate the high activity of biolipid conversion.

Simultaneous bioremediation of Disperse orange-2RL Azo dye and fatty acids production by Scenedesmus obliquus cultured under mixotrophic and heterotrophic conditions

Several types of green photosynthetic microalgae can grow through the process of heterotrophic growth in the dark with the help of a carbon source instead of the usual light energy. Heterotrophic growth overcomes important limitations in the production of valuable products from microalgae, such as the reliance on light, which complicates the process, raises costs, and lowers the yield of potentially useful products. The present study was conducted to explore the potential growth of green microalga Scenedesmus obliquus under mixotrophic and heterotrophic conditions utilizing Disperse orange 2RL Azo dye as a carbon source to produce a high lipid content and the maximum dye removal percentage. After 7 days of algal growth with dye under mixotrophic and heterotrophic conditions with varying pH levels (5, 7, 9, and 11), KNO3 concentrations (1, 1.5, 2, and 3 g/L), and dye concentrations (20, 40, and 60 ppm); dye removal percentage, algal dry weight, and lipid content were determined. The results showed that the highest decolorization of Disperse orange 2RL Azo dye (98.14%) was attained by S. obliquus in heterotrophic medium supplemented with glucose at the optimal pH 11 when the nitrogen concentration was 1 g/L and the dye concentration was 20 ppm. FT-IR spectroscopy of the dye revealed differences in peaks position and intensity before and after algal treatment. S. obliquus has a high concentration of oleic acid, which is enhanced when it is grown with Disperse orange 2RL Azo dye, making it ideal for production of high-quality biodiesel. In general, and in the vast majority of instances, heterotrophic cultivation is substantially less expensive, easier to set up, and requires less maintenance than mixotrophic cultivation. Heterotrophic cultivation allows for large-scale applications such as separate or mixed wastewater treatment along with biofuel production.