Potential Feedstock For Biodiesel Production Research Articles

Evaluation of the potential of activated sludge biomass from Nigeria as a feedstock for biodiesel production

AbstractDepleting fossil fuel reserves and the effects of greenhouse gases on climate change have led to the investigation of alternative energy sources such as biofuel, including biodiesel and renewable diesel. Unfortunately, the cost of the feedstock exceeds 70% of the total production cost. The current work investigates the potential of utilizing a waste product (activated sludge biomass) from wastewater treatment, as an alternative feedstock for biodiesel production. The activated sludge biomass was pretreated with subcritical water to enhance the lipid yield before extracting the lipid using solvent extraction. The result showed that lipid yield from the activated sludge was 4.73–8.58%. After subcritical water pretreatment with varying residence time, temperature, and biomass loading, the lipid yield increased by 158.04–400%. Gas chromatography–mass spectrometry (GC–MS) analysis of the fatty acid methyl esters (FAME) from the transesterification of the lipid extract using calcined egg shell as a catalyst identified the following lipids: triglyceride, fatty acids, sphingolipid, phospholipid, glycerolipid, glycerophospholipid, steroid, and cholesterol. The predominant lipid was triglyceride, and the high percentage of unsaturated fatty acids, including arachidonic acid (23.54%), eicosadienoic acid (8.37%), and oleic acid (6.23%) suggest that the lipid extract is a potential feedstock for biodiesel production.

Recycled waste groundnut oil: A potential feedstock for green energy/biodiesel synthesis

This work focuses on the recycling of waste groundnut oil as a potential feedstock for biodiesel production using activated coconut husk as a regenerating agent. The coconut husk was functionalized using organic acid. The properties of the functionalized coconut husk were investigated via instrumental analysis. Non-parametric modeling involving 2-degree isotherm models were used. The regeneration/recycling of the waste oil were done in batch mode examining key factors of temperature, time, concentration and dosage. Biodiesel was synthesized from recycled waste groundnut oil using transesterification reaction. The properties of biodiesel were examined using ASTM and AOAC official standards. Brunauer-Emmett-Teller surface analysis revealed the surface area of the adsorbent as 371.88 m2/g and a porosity distribution of 0.567 η on the surface at a pH of 6.1. Batch mode analysis revealed that 97.5% of impurities was removed from waste groundnut oil under one batch process at 80 °C after 4 h with 6 g of the activated coconut husk. Langmuir isotherm model provided the best fit to the experimental data with adsorption capacity of 33.5 mg/g at R2 of 0.996. Adsorption of waste groundnut oil impurities onto activated coconut husk was endothermic, as evidenced by the calculated ΔH of +2.7914 kJ/mol. A high cetane number of 48.4 obtained after transesterification is an indication of the good ignition quality of the obtained recycled waste groundnut oil methyl ester. Kinematic viscosity and acid value were revealed to be 4.65 mm2 S−1 and 0.31 mg KOH/g, while the calorific value stood at 38,053 kJ/kg. GC-MS analysis revealed a complex mixture of fatty acid methyl esters dominated by unsaturated fatty acids (58.78%). Recycling of waste cooking oil in this work using activated coconut husk demonstrated good quality as a regenerating agent. The properties of biodiesel obtained showed that it has all the good qualities comparable to other existing biodiesel based on the ASTM and AOAC official standards. More work on the recycling of other waste cooking oils for green energy synthesis to protect our environment from pollution emanating from the use of conventional petro-diesel and promote energy transition is highly recommended.

Effectiveness of <i>Jatropha curcas</i> as Biodiesel and Antiviral: A Review

Jatropha curcas has emerged as a potential feedstock for biodiesel production due to its non-edible nature, high oil content, and adaptability to marginal lands. This review provides an overview of the advantages and challenges associated with Jatropha curcas as a biodiesel source. The non-edible nature of Jatropha curcas makes it an attractive option for biofuel production, as it does not compete with food crops, minimizing concerns about food security. The seeds of Jatropha curcas contain a significant amount of oil, ranging from 30% to 40%, making it a suitable feedstock for biodiesel production. Jatropha curcas exhibits adaptability to harsh environments and can grow on marginal lands unsuitable for food crops. It requires low water and nutrient inputs, making it a potential solution for areas where other crops struggle to thrive. Furthermore, the cultivation of Jatropha curcas can provide economic opportunities, especially in rural areas, contributing to rural development and income generation for farmers. However, there are challenges that need to be addressed for the successful commercialization of Jatropha curcas as a biodiesel feedstock.

Environmental assessment of Rhodosporidium toruloides-1588 based oil production using wood hydrolysate and crude glycerol

Rhodosporidium toruloides, an oleaginous yeast, is a potential feedstock for biodiesel production due to its ability to utilize lignocellulosic biomass-derived hydrolysate with a considerably high lipid titer of 50–70 % w/w. Hence, for the first-time environmental assessment of large-scale R. toruloides-based biodiesel production from wood hydrolysate and crude glycerol was conducted. The global warming potential was observed to be 0.67 kg CO2 eq./MJ along with terrestrial ecotoxicity of 1.37 kg 1,4-DCB eq./MJ and fossil depletion of 0.13 kg oil eq./MJ. The highest impacts for global warming (∼45 %) and fossil depletion (∼37 %) are attributed to the use of chloroform for lipid extraction while fuel consumption for transportation contributed more than 50 % to terrestrial ecotoxicity. Further, sensitivity analysis revealed that maximizing biodiesel yield by increasing lipid yield and solid loading could contribute to reduced environmental impacts. In nutshell, this investigation reveals that environmental impact varies with the type of chemical utilized.

Cashew nut shell oil as a potential feedstock for biodiesel production: An overview.

Biodiesel outperforms diesel in emissions and engine performance. They burn efficiently in diesel engines and are eco-friendly. Since cashew nut shell liquid (CNSO) is waste, commercial biodiesel production from it should be profitable. CNSO is cheap and can reduce cashew processing factory waste. From cashew kernels, CNSL is extracted using various mechanical, thermal, and solvent extraction techniques. This article examines current research into using cashew nutshell liquid biodiesel (CNSLBD) in diesel engines. The work also discusses Indian biodiesel demand, availability, export information, life cycle cost analysis, cost economics of per hectare yield, Indian government initiative of CNSO. This review also evaluates the viability of this fuel as an alternative energy source. CNSLBD is a prospective alternative fuel that has the potential to benefit both the cashew nut industry and the energy industry. In addition to this, the study examines the procedures for extracting CNSO. According to the findings of the study, CNSO is a prospective alternative fuel that has the potential to benefit both the cashew nut industry and the energy industry.

Potential non-edible oil seeds for biodiesel production: An Indian context

Both energy demand and energy security are major concerns for all the economies worldwide due to the rising rate of energy consumption and rise in energy consumption per capita. In addition, the use of biofuels in place of conventional petroleum-based fuels has received more attention as a result of the global commitment to environmentally friendly and sustainable energy use. Biodiesel has emerged as potential biodegradable and nontoxic fuel, which significantly decreases toxic and other harmful emissions when used as diesel engine fuel. The major advantages of biodiesel include its higher cetane number, higher combustion efficiency, lower emissions of aromatic and sulfurous compounds, and a high flash point. The current paper discusses about different potential feedstocks for biodiesel production, its properties and impact of combustion of biodiesel on the environment. The findings of the number of biodiesel related studies and techniques to enhance the performance of the biodiesel fueled engines are covered in this paper. The prospects of economics of biodiesel used in India as a blend are also highlighted in the paper.

Optimization of ultrasound-assisted oil extraction from Carica candamarcensis; A potential Oleaginous tropical seed oil for biodiesel production

This study focuses on the optimization of ultrasound-assisted oil extraction from Carica candamarcensis seed using response surface methodology. The process parameters considered were extraction time (30–60 min), ultrasound amplitude level (20–40%), and solvent to seed ratio (10–20 mL/g). These were varied as suggested by Box-Behnken experimental model. Optimum values of these process parameters were given by the regression model, with the corresponding extraction yield. The model was validated experimentally to ensure its reliability. Physicochemical properties and fatty acid compositions of the extracted oil were evaluated accordingly. Furthermore, the extracted oil was then converted into biodiesel via ultrasound-assisted transesterification, using potassium hydroxide as the catalyst. FAME contents of the produced biodiesel were measured using gas chromatography. In addition, physicochemical properties of the biodiesel were also determined accordingly. Hence, findings from this study would be beneficial in further exploration on the usage of Carica candamarcensis as a potential feedstock for biodiesel production.

Techno-economic identification of production factors threatening the competitiveness of algae biodiesel

The majority belief is that microalgae is the most promising potential feedstock for biodiesel production while it can also be used for treating wastewater. After the microalgae biodiesel is mixed with proper additives, it can even outperform some conventional fossil fuels, not to mention its environmentally friendly nature. Although the mainstream view is that microalgae production costs are small and will be even smaller once mass production is implemented, no reviewable reports are traceable to support these claims. Only a few studies are available that address the commercialization aspects of microalgae mass production and the economy of its subsequent refining into biodiesel. The prevailing view is that microalgae cultivation is fully mastered, while most production costs refer to energy consumption, where there is much room for optimization. The current review focuses on the financial aspects of microalgae production via bioreactors. Economic considerations are also given to the less common alternatives such as harvesting from natural habitats, production of biogas, or nutrient regeneration. Synergies from the combination of these methods are also taken into account. Our analysis confirmed that the cost-competitive microalgae biodiesel business strongly depends on the microalgae production cost, which is strongly defined by the running cost of the production technology. However, it is claimed that no technology could be found that was ready to be transformed into commercial dimensions and made it possible to produce microalgae at a price that creates at least a remote possibility of running profitable algae biodiesel business in the current state of the market.

Cultivation of Pseudochlorella pringsheimii for biodiesel production in a scalable indoor photobioreactor: case studies from Egypt

BackgroundEnhancement of lipid accumulation is the major strategy to improve the commercial feasibility of microalgae as a source for biodiesel production. Pseudochlorella pringsheimii (Formally was named as Chlorella ellipsoidea) green microalgae strain was chosen with respect to their ability as a potential source to produce high lipids content, could be used for the production of biofuel, which can be an alternative renewable energy source instead of fossil fuels. ResultsInitially, the Pseudochlorella pringsheimii microalgae was evaluated on the basis of tested at Lab scales 2 L by applicable different nutrient individual of N, P, Fe conditions in BBM medium concentrations for choosing the best concentrations induce lipid contents and productivity to cultivate in large scale in the 2000 L PBR. The suitable concentrations of nutrients with highest lipid contents were obtained under deficient of nitrogen (1.25 gL−1, limited N) and phosphorus (0.1 mg L−1, limited P) coupled with high iron concentration (10 mg L, rich Fe) and CO2 (6%). Therefore, their collective of nutrients was applied to culture of microalgae cells at large scale in 2000 L photobioreactor (PBR model), which, this techniques was used to quantify high lipid contents (25% w/w) and high lipid productivity (74.07 mgL−1 day−1). The inducted lipid conversion to biodiesel via transestrification process was 91.54 ± 1.43%. The fatty acid methyl esters (FAMEs profile by means of GC/MS resulted in C16:0, C18:1, C18:2, C18:3 as a main constituents. With regard to physical–chemical property (such as density, kinematic viscosity, gravity, and certain number), the Pseudochlorella pringsheimii biodiesel have biofuel properties, in accordance with appropriate biodiesel properties, as ASTM and EU standards, that thereby referring to high quality biodiesel. ConclusionsPseudochlorella pringsheimii cultured in large scale in photobioreactor under stress condition have a high potential of lipids production with high quality of FAMEs that can be used as a promising biodiesel fuel. It has also a potential to be applied for commercialization based on the techno-economic and environmental impacts. Highlights*Pseudochlorella pringsheimii showed a high potential of lipids 25% lipid accumulation.*Pseudochlorella pringsheimii could be cultured at large scale in potobioreactor, as potential feedstock for biodiesel production.*Bodiesel FAME contains C 16:0, C 18:1 and C 18:2 as a maim FAM.*N, P starvation collective with high Fe3+was the main driver behind lipid accumulation.*Pseudochlorella pringsheimii biodiesel have appropriate biodiesel properties, as ASTM and EU standards.*C. ellipsoidea can be used as a potential feedstock for biodiesel production.

Single cell oil of oleaginous marine microbes from Saudi Arabian mangroves as a potential feedstock for biodiesel production

This study aims to explore microbes from mangroves in Saudi Arabia for their abilities to produce high level of lipids. Mangroves are seldom investigated for oleaginous microbes. A total of 961 isolates of yeasts and filamentous fungi were isolated from 144 submerged marine samples include: 68 decaying leaves of Avicennia marina, 33 decaying thalli of Zostera marina, 14 decaying pneumatophores of Avicennia marina, 9 crab shells, 8 sediment, 7 decaying thalli of Turbinaria ornata and 5 decaying thalli of Cystoseira myrica. Samples were collected from four mangrove sites: Al-Leith, Jeddah and Yanbu at the Red Sea coast and the Syhat mangroves at the Arabian Gulf coast. Isolated fungi were grouped into 62 morphological types that include: 21 yeasts and 41 filamentous fungi. Fifty-four isolates of thraustochytrids were cultured from the four mangrove sites and were grouped into 22 strains. Two oleaginous yeasts: Hortaea werneckii and Rhodotorula mucilaginosa and four Aurantiochytrium strains produced high dry weight ranged between 32 and 49.3 g/L of which 35.2–62 % lipid and their fatty acid profile were determined using GC/MS. Palmitic acid was the major fatty acid in the lipid of the four thraustochytrid isolates and ranged between 5.71 and 82 % of the total fatty acids, 9-Octadecenamide, (Z)- was the major fatty acid amide in the lipid of the two yeast isolates and two thraustochytrid isolates and ranged between 26.94 and 56.63 %, followed by 13-Docosenamide, (Z)- (20.44–34.99 %) from the same four isolates. Other major lipid compounds were: Hexadecanamide (4.35–7.19 %), Cholestrol (7.24–15.07 %), Butylated Hydroxytoluene (3.46–15.76 %), Octadecanamide (3.95–7.9 %), Phenol, 2-(1,1-dimethylethyl)-5-methyl- (1.78–10.33 %) and Pentadecanoic acid (7.47 %).

Watermelon (Citrullus vulgaris) seed oil as a potential feedstock for biodiesel production in Nigeria

Biodiesel fuel was successfully synthesized from Nigerian Watermelon (Citrullus vulgaris) seed oil through direct base-catalysed transesterification process using Methanol and sodium hydroxide as alcohol and catalyst, respectively. The solvent extraction method was used to extract the watermelon oil from the seed in order to determine its physic-chemical properties for relevant uses. Physical properties of the watermelon seed oil, its biodiesel and biodiesel blends were measured using the American Society for Testing and Materials (ASTM) methods for biodiesel and diesel fuels. Also, the effect of temperature and catalyst concentration on the biodiesel yield was studied. The properties of the produced watermelon oil and its biodiesel fuel were compared with that of vegetable oils from other feedstock and their respective biodiesel fuels. The result showed that the calorific value of the produced watermelon biodiesel is 40.10 MJ/Kg while that of the watermelon seed oil is 38.24 MJ/Kg. The cetane number, kinematic viscosity at 40 °C and pour point of the produced oil are 39.38, 8.50 mm2/s and 15 °C while that of the produced biodiesel are 53.165, 5.82mm2/s and 3 °C for Watermelon biodiesel, respectively. The maximum biodiesel yield (93.68%) was recorded at 55 °C with catalyst concentration of 1.0% of sodium hydroxide (NaOH) by weight. In comparison to biodiesel produced from other feedstock, the lower heating value and cetane number of watermelon seed oil methyl ester (40.10 MJ/kg and 53.165) were higher than that of palm kernel biodiesel (39.30 MJ/kg and 52.30), castor biodiesel (30.50 MJ/kg and 50), sandbox seed biodiesel (37.00 MJ/kg and 50), dika nut biodiesel (39.00 MJ/kg and 52) and kapok fibre biodiesel (40.064 MJ/kg), while that of physic nut biodiesel were higher. The obtained properties of watermelon seed oil and its biodiesel conformed to the ASTM standards for biodiesel and diesel fuels. The results further showed that watermelon seed oil is a potential feedstock for biodiesel production and the biodiesel produced can serve as an alternative fuel for diesel engines.

Evaluation of Sesame Seed Oil as a Potential Feedstock for Biodiesel Production

Evaluation of Sesame Seed Oil as a Potential Feedstock for Biodiesel Production

Enhancing biomass and lipid productivity of a green microalga Parachlorella kessleri for biodiesel production using rapid mutation of atmospheric and room temperature plasma

BackgroundMicroalgae, with their high adaptability to various stress conditions and rapid growth, are considered excellent biomass resources for lipid production and biodiesel feedstocks. However, lipid yield and productivity of the natural strains are common bottlenecks in their large-scale use for lipid production, which can be overcome by evolving new strains using conventional and advanced mutagenic techniques. It is challenging to generate microalgae strains capable of high lipid synthesis through natural selection. As a result, random mutagenesis is currently considered a viable option in many scenarios. The objective of this study was to explore atmospheric and room temperature plasma (ARTP) as a random mutagenesis technique to obtain high lipid-accumulating mutants of a green microalga for improved biodiesel production.ResultsA green microalgal species was isolated from the Chinese Yellow Sea and identified as Parachlorella kessleri (OM758328). The isolated microalga was subsequently mutated by ARTP to obtain high lipid-accumulating mutants. Based on the growth rate and lipid content, 5 mutants (named M1, M2, M4, M5, and M8) were selected from 15 pre-selected mutants. These five mutants varied in their growth rate from 0.33 to 0.68 day−1, with the lipid content varying between 0.25 g/L in M2 to 0.30 g/L in M8 at 10th day of cultivation. Among the mutants, M8 showed the maximum biomass productivity (0.046 g/L/day) and lipid productivity (20.19 mg/L/day), which were 75% and 44% higher than the wild strain, respectively. The triglyceride (TAG) content of M8 was found to be 0.56 g/L at 16th day of cultivation, which was 1.77-fold higher than that of the wild strain. Furthermore, M8 had the highest saturated fatty acids (C16-18) with the lowermost polyunsaturated fatty acid content, which are favorable properties of a biodiesel feedstock according to international standards.ConclusionThe mutant strain of P. kessleri developed by the ARTP technique exhibited significant improvements in biomass productivity, lipid content, and biodiesel quality. Therefore, the biomass of this mutant microalga could be a potential feedstock for biodiesel production.

Biodiesel synthesis from waste canarium schweinfurtii oil (WCSO) catalyzed by thermal reinforced clay and its kinetics evaluation

The synthesis of biodiesel from waste local materials and kinetics of heterogeneous catalyzed transesterification was carried out. The local materials used were waste canarium schweinfurtii oil (WCSO) and clay. The oil was extracted from the seeds by solvent extraction method and characterized using American Society for Testing Materials (ASTM 02). The clay was reinforced thermally by heating it in a muffle furnace at a temperature of 700 °C and characterized using instrumental analysis to identify its catalytic properties. The kinetic investigation of the heterogeneous catalyzed transesterification of WCSO was done using Eley-Rideal (ER) mechanism. The results revealed that WCSO is a potential feedstock for biodiesel production with oil yield of 50.11 % and its physiochemical properties were suitable for heterogeneous catalysis. The thermally reinforced clay exhibited catalytic properties required for conversion of WCSO triglyceride to biodiesel with 85.3 % yield of 85.3 %. The experimental data well fitted to ER kinetic model with 95 % level of significance. The rate controlling step for reaction was surface reaction between adsorbed triglyceride and non-adsorbed methanol with lower activation energy of 4.53 kJ/mol for forward reaction. Hence, it is economical to produce biodiesel from waste canarium schweinfurtii oil via transesterification reaction catalyzed by thermally reinforced clay.

Dairy waste scum as a potential feedstock for bio-diesel production: optimisation, quality and reliability studies

ABSTRACT Dairy waste scum obtained from the downstream milk production process is a potential source to produce biodiesel. It’s a less dense floating solid mass that primarily consists of triglycerides and fatty acids, which are important constituents for fuel. The present study aims to produce biodiesel using dairy waste scum by a transesterification process using NaOH/KOH catalysts. The present work identifies the better catalyst between two alkaline catalysts NaOH and KOH, using low-cost methodologies. The preliminary confirmation characteristics, such as density, calorific value, Kinematic Viscosity, Specific Gravity, Flash Point, and Fire Point will support the formation of synthesised biodiesel via the proposed methodology. The experimental results lead to a yield of 89.02% of biodiesel using NaOH catalyst with optimised process parameters of the temperature of 55°C, the reaction time of 120 min, and catalyst loading of 1 wt./wt.%. Finally, biodiesel was tested for emission and combustion characteristics in a CI engine. To optimise the process parameters, the response surface methodology (RSM) along with Bootstrap estimation has been performed using MINITAB19. Furthermore, the experimental and predicted yields obtained from ANOVA were reported.

Utilization of indigenous gurgure (Monotheca Buxifolia) waste seeds as a potential feedstock for biodiesel production using environmentally benign bismuth modified CaO catalyst

Herein, we report the synthesis of Bi2O3 modified CaO heterogeneous catalyst for biodiesel production from low valued gurgure (Monotheca Buxifolia) seed oil to develop profitable and sustainable approach. The catalysts were analyzed by X-ray diffractometer (XRD), Brunauer-Emmett-Teller (BET), Temperature programming desorption of CO2 (TPD-CO2), Field emission scanning electron microscopy (FESEM), Energy dispersive X-ray (EDX). The activity evaluation results indicated that the CaO-Bi2O3 catalyst enriched with 20 wt% Bi2O3 loading displayed an excellent catalytic performance providing biodiesel yield of 98.7% under optimum reaction parameters of oil to methanol molar ratio 1:12, 65 °C reaction temperature in 2 hr of reaction time and catalyst loading of 6 wt%. The catalyst depicted better reusability upto six reaction cycles and hence the cost of the biodiesel could be reduced effectively. Response surface methodology (RSM) based on central composite design (CCD) was also applied to investigate the influence of reaction parameters. The statistical deign results showed good consistent with the experimental data, providing p-vale of 0.000 i.e. high level of significance of the model. Finally, it could be summarized that the synthesized catalyst demonstrated remarkable activity and durability in term of biodiesel yield using gurguray oil as a cheap and non-edible feedstock.

Optimization of Biodiesel Production Parameters from Cucurbita maxima Waste Oil Using Microwave Assisted via Box-Behnken Design Approach

The production of biodiesel from vegetables or fruits waste oils has high potential as renewable energy. The Cucurbita maxima wastes are massive source of oils, which are believed to indicate the possible sources of renewable energy whose biodiesel can be produced. Hence, the study explores the potential of the Cucurbita maxima wastes, for the production of biodiesel. In this study, the Soxhlet extraction method was used to extract Cucurbita maxima waste oil using an organic solvent. Through Box-Behnken design (BBD), the effects of methanol to oil molar ratio (6–10), catalyst concentration (2–6%), and reaction time (45–75 min) on the transesterification efficiency of methyl esters were investigated. The oil contents of Cucurbita maxima waste was found to be 44.6 ± 0.21 %. This oil was characterized, and after obtaining the pure characterized oil, biodiesel was produced using microwave assisted by the transesterification process. The optimum conversion efficiency of the Cucurbita maxima waste oil to fatty acid methyl ether was 97.76%, at the optimal parameters, methanol to oil ratio (8.4 : 1), catalyst concentration (3.14%), and reaction time (57.12 min). The results revealed that all parameters have a significant effect on the yield of biodiesel ( p < 0.0001 ). The physicochemical properties reveal that the Cucurbita maxima waste oil could be applied as a potential source of material for methyl ester production. The fatty acid profile of the oil indicated that it was mainly composed of unsaturated fatty acid, which ensures good flow properties of the fuel. The results of these studies showed the prospective of Cucurbita maxima wastes as a new potential feedstock for biodiesel production.

Biochemical and Morphological Changes Triggered by Nitrogen Stress in the Oleaginous Microalga Chlorella vulgaris.

Oleaginous microalgae have been considered promising sources of biodiesel due to their high lipid content. Nitrogen limitation/starvation is one of the most prominent strategies to induce lipid accumulation in microalgae. Nonetheless, despite numerous studies, the mechanism underlying this approach is not well understood. The aim of this study was to investigate the effect of nitrogen limitation and starvation on biochemical and morphological changes in the microalga Chlorella vulgaris FACHB-1068, thereby obtaining the optimal nitrogen stress strategy for maximizing the lipid productivity of microalgal biomass. The results showed that nitrogen limitation (nitrate concentration < 21.66 mg/L) and starvation enhanced the lipid content but generally decreased the biomass productivity, pigment concentration, and protein content in algal cells. Comparatively, 3-day nitrogen starvation was found to be a more suitable strategy to produce lipid-rich biomass. It resulted in an increased biomass production and satisfactory lipid content of 266 mg/L and 31.33%, respectively. Besides, nitrogen starvation caused significant changes in cell morphology, with an increase in numbers and total size of lipid droplets and starch granules. Under nitrogen starvation, saturated fatty acids (C-16:0, C-20:0, and C-18:0) accounted for the majority of the total fatty acids (~80%), making C. vulgaris FACHB-1068 a potential feedstock for biodiesel production. Our work may contribute to a better understanding of the biochemical and morphological changes in microalgae under nitrogen stress. Besides, our work may provide valuable information on increasing the lipid productivity of oleaginous microalgae by regulating nitrogen supply.

Impact of Culture Media Composition, Nutrients Stress and Gamma Radiation on Biomass and Lipid of the Green Microalga, Dictyochloropsis splendida as a Potential Feedstock for Biodiesel Production

Biodiesel production from microalgae depends on the biomass and lipid production. Both biomass and lipid accumulation is controlled by several factors. The effect of various culture media (BG11, BBM, and Urea), nutrients stress [nitrogen (N), phosphorous (P), magnesium (Mg) and carbonate (CO3)] and gamma (γ) radiation on the growth and lipid accumulation of Dictyochloropsis splendida were investigated. The highest biomass and lipid yield of D. splendida were achieved on BG11 medium. Cultivation of D. splendida in a medium containing 3000 mg L−1 N, or 160 mg L−1 P, or 113 mg L−1 Mg, or 20 mg L-1 CO3, led to enhanced growth rate. While under the low concentrations of nutrients caused a marked increase in the lipid content. Cultures exposure to 25 Gy of γ-rays, led to an increase in lipid content up to 18.26 ± 0.81 %. Lipid profile showed the maximum presence of saturated fatty acids (SFAs, 63.33%), and unsaturated fatty acids (UFAs, 37.02%). Fatty acids (FAs) recorded the predominance of C16:0, C18:2, C15:0 and C16:1, which strongly proved D. splendida is a promising feedstock for biodiesel production.

Experimental Investigation and Optimization of Non-Catalytic In-Situ Biodiesel Production from Rice Bran Using Response Surface Methodology Historical Data Design

Rice bran oil (RBO)is claimed to be a potential feedstock for biodiesel production. Non-catalytic in-situ biodiesel production from a low-cost feedstock (rice bran) using subcritical ethanol-water mixture was investigated in this study. The influence of four independent variables, i.e., addition of co-solvent, ethanol concentration, temperature, and time of reactions, on the yield of biodiesel was examined. The results showed that the most effective co-solvent wasethyl acetate and the optimum ethanol concentration, temperature and reaction time were 80% v/v, 200 oC and 3 hours, respectively. The maximum yield of biodiesel was found to be around 80%. The optimization of operating conditions was carried out by response surface methodology (RSM) with historical data design (HDD). The statistical method also suggested similar optimum operating conditions, i.e., 78.44% (v/v) ethanol concentration, 200 oC, and 3.2 hours reaction time with ethyl acetate as a co-solvent. The predicted maximum biodiesel yield was also slightly lower, i.e., 76.98%. Therefore, this study suggests that biodiesel production from rice bran through a non-catalytic in-situ process using a subcritical ethanol-water mixture with ethyl acetate as a co-solvent is very feasible since the yield can reach 80%. The study also found that RSM with HDD can predict the optimum operating conditions with a good accuracy.