Pumpkin (Cucurbita pepo L.) seed oil as an alternative feedstock for the production of biodiesel in Greece

In recent years, the acceptance of fatty acid methyl esters (biodiesel) as a substitute to petroleum diesel has rapidly grown in Greece. The raw materials for biodiesel production in this country mainly include traditional seed oils (cotton seed oil, sunflower oil, soybean oil and rapeseed oil) and used frying oils. In the search for new low-cost alternative feedstocks for biodiesel production, this study emphasizes the evaluation of pumpkin seed oil. The experimental results showed that the oil content of pumpkin seeds was remarkably high (45%). The fatty acid profile of the oil showed that is composed primarily of linoleic, oleic, palmitic and stearic acids. The oil was chemically converted via an alkaline transesterification reaction with methanol to methyl esters, with a yield nearly 97.5 wt%. All of the measured properties of the produced biodiesel met the current quality requirements according to EN 14214. Although this study showed that pumpkin oil could be a promising feedstock for biodiesel production within the EU, it is rather difficult for this production to be achieved on a large scale.     

High free fatty acid coconut oil as a potential feedstock for biodiesel production in Thailand

Coconut oil having 12.8% free fatty acid (FFA) was used as a feedstock to produce biodiesel by a two-step process. In the first step, FFA level of the coconut oil was reduced to 0.6% by acid-catalyzed esterification. In the second step, triglycerides in product from the first step were transesterified with methanol by using an alkaline catalyst to produce methyl esters and glycerol. Effect of parameters related to these processes was studied and optimized, including methanol-to-oil ratio, catalyst concentration, reaction temperature, and reaction time. Methyl ester content of the coconut biodiesel was determined by GC to be 98.4% under the optimum condition. The viscosity of coconut biodiesel product was very close to that of Thai petroleum diesel and other measured properties met the Thai biodiesel (B100) specification.     

橡胶籽油制备生物柴油的工艺研究

实验研究了乙醇钠催化下橡胶籽油与乙醇进行酯交换反应制备生物柴油的工艺条件。通过正交实验和单因素实验,发现酯交换反应的最佳工艺条件:催化剂用量为油重的1.0%,醇油物质的量比为15∶1,反应温度为78℃,搅拌时间为120 min,在此反应条件下,橡胶籽油转化率为92.14%。     

Muskmelon (Cucumis melo) seed oil: A potential non-food oil source for biodiesel production

Methanolysis of muskmelon seed oil was optimized employing RSM (response surface methodology). Four process variables were evaluated at two levels: methanol/oil molar ratio (3:1–12:1), catalyst concentration in relation to oil mass (0.25–1.25 wt % KOH), reaction temperature (25–65 °C) and methanolysis reaction time (20–90 min). Multiple regression analysis was employed to get the quadratic polynomial equation for predicting transesterification using RSM. The result indicated that catalyst concentration and reaction temperature were the important factors that significantly affect the yield of MMOMEs (muskmelon oil methyl esters)/biodiesel. The RSM methodology was used to obtain methyl esters yield (89.5%) were found at following reaction conditions; 5.8:1 methanol-to-oil ratio, 0.79% catalyst concentration, 55 °C reaction temperature and 72.5-min reaction time. There was a linear correlation between observed and predicted values. The biodiesel was analyzed using GC/MS (gas chromatography/mass spectrometry) which indicated four FAMEs (fatty acid methyl esters) (linoleic-, oleic-, palmitic- and stearic acids) as its major components. The FT-IR (fourier transform infraRed) spectrum of MMOMEs was also acquired to ensure the confirmation of methyl esters formation. Fuel properties of MMOMEs were determined and found to satisfy the ASTM D 6751 and EU 14214 specifications.     

Cyprinus carpio fish oil: A novel feedstock for biodiesel production

Biodiesel was developed from a novel nonedible oil source, namely Cyprinus carpio fish oil. The acid value of fish oil was very low (0.70 mg KOH/g oil, 0.35 free fatty acid content). As a result, biodiesel was produced through a one-step transesterifcation process, i.e. alkali-catalyzed transesterification with methanol. The optimal conditions for producing biodiesel from fish oil were investigated. The highest biodiesel yield (97.22% ~ 96.88% w/w ester content) was obtained under optimum conditions of 0.75% KOH w/w, 7:1 methanol to oil molar ratio, 60°C reaction temperature and 60-minute duration. Properties of the produced biodiesel as well as its blends with petro-diesel fulfilled the standard limits as prescribed by ASTM D6751 and EN 14214 indicating its suitability as a fuel for diesel engines.     

Okra (Hibiscus esculentus) seed oil for biodiesel production

Biodiesel was derived from okra (Hibiscus esculentus) seed oil by methanol-induced transesterification using an alkali catalyst. Transesterification of the tested okra seed oil under optimum conditions: 7:1 methanol to oil molar ratio, 1.00% (w/w) NaOCH₃ catalyst, temperature 65 °C and 600 rpm agitation intensity exhibited 96.8% of okra oil methyl esters (OOMEs) yield. The OOMEs/biodiesel produced was analyzed by GC/MS, which showed that it mainly consisted of four fatty acids: linoleic (30.31%), palmitic (30.23%), oleic (29.09%) and stearic (4.93%). A small amount of 2-octyl cyclopropaneoctanoic acid with contribution 1.92% was also established. Fuel properties of OOMEs such as density, kinematic viscosity, cetane number, oxidative stability, lubricity, flash point, cold flow properties, sulfur contents and acid value were comparable with those of ASTM D 6751 and EN 14214, where applicable. It was concluded that okra seed oil is an acceptable feedstock for biodiesel production.     

Potential of microalgae oil from Dunaliella tertiolecta as a feedstock for biodiesel

Alternative, non-food based biomass fuel feedstock development is vital for our national security, economy and the environment. Microalgae are among the most promising of these alternatives. Microalgal cell growth rates and metabolic products are affected by a combination of environmental parameters. In this work, the influences of light source, light intensity, CO₂ concentration, and photoperiod on the growth of Dunaliella tertiolecta (D. tertiolecta) were studied. The effects of these environmental parameters on the lipid content and fatty acid composition of D. tertiolecta were also investigated. Red light-emitting diodes (LEDs), white LEDs, and fluorescent lights were all found to be effective for algal growth. Increasing light intensity resulted in significantly more rapid algal growth, and increasing the period of light also significantly increased biomass productivity. Similar growth rates were observed for 2%, 4%, and 6% CO₂-concentrations. The different light sources and intensities were found to have no significant effect on FAME composition of D. tertiolecta. Methyl linolenate and methyl palmitate were found to be the major components of FAME produced from D. tertiolecta oil. D. tertiolecta and its derived oils should be a suitable feedstock for biofuel production.     

Transesterification of non-edible seed oil for biodiesel production: characterization and analysis of biodiesel

Evaluation of Radish (Raphanus sativus) seed oil (RSO) as a non-edible feedstock for biodiesel production was the main target of the present study. Extraction by solvent disclosed that radish seeds contains 33.50 wt.% of oil. Therefore, biodiesel production from it could be beneficial. Optimized base-catalyzed transesterification of RSO with methanol, ethanol and mixed methanol/ethanol was performed, to produce fatty acid methyl esters, fatty acid ethyl esters and mixed fatty acid methyl ethyl esters, respectively. The optimal yields of the methyl esters, ethyl esters and mixed methyl ethyl esters, were 95.55wt.%, 90.66 wt.% and 93.33 wt.%, respectively when the optimal reaction conditions were attained. Fuel properties of the parent oil were positively changed as consequence of transesterification reaction such that they fulfilled the standard limits as prescribed by ASTM D6751. Moreover, fuel properties of (biodiesels + petro diesel) blends conformed ASTM D7467-17 standards indicating their suitability as a fuel for diesel engines. Biodiesels form RSO were analyzed by thin layer chromatography and FTIR spectroscopy, and both techniques conformed its conversion into its corresponding alkyl esters.     

Whey waste as potential feedstock for biohydrogen production

In-house isolate Clostridium sp. IODB-O3 was exploited for biohydrogen production using cheese whey waste in batch fermentation. Analysis of cheese whey shows, it is enriched with lactose, lactic acid and protein components which were observed most favourable for biohydrogen production. Biohydrogen yield by IODB-O3 was compared with the cultures naturally occurring in waste solely or in combinations, and found that Clostridium sp. IODB-O3 was the best producer. The maximum biohydrogen yield obtained was 6.35 ± 0.2 mol-H₂/mol-lactose. The cumulative H₂ production (ml/L), 3330 ± 50, H₂ production rate (ml/L/h), 139 ± 5, and specific H₂ production (ml/g/h), 694 ± 10 were obtained. Clostridium sp. IODB-O3 exhibited better H₂ yield from cheese whey than the reported values in literature. Importantly, the enhancement of biohydrogen yield was observed possibly due to absence of inhibitory compounds, presence of essential nutrients, protein and lactic acid fractions which supported better cell growth than that of the lactose and glucose media. Carbon balance was carried out for the process which provided more insights in IODB-O3 metabolic pathway for biohydrogen production. This study may help for effective utilization of whey wastes for economic large scale biohydrogen production.     

Nipa (Nypa fruticans) sap as a potential feedstock for ethanol production

The current study was initiated to evaluate the potential of sugar saps from nipa (Nypa fruticans) palm as sustainable feedstock for ethanol production. Nipa palms managed as plantations on four sites was chosen for this study with palms within 8–100 years of age. All palms studied were found to have the potential to produce sugar saps from 0.4 to 1.2 L d^-1 per palm. Further chemical characterization of its saps gave a total composition of 159–214 g kg^-1 mainly composed of sucrose, glucose and fructose. In addition, the elemental analysis gave 5 g kg^-1 of inorganics with Na, K and Cl being its main inorganic elements. Preliminary batch fermentative assays using Saccharomyces cerevisiae showed that nipa saps can be converted to ethanol within 30–48 h in conditions with and without nutrient supplementation. Furthermore, the fermentation trends were similar to sugarcane sap with high ethanol conversions up to 96.9% and 95.5% achieved for both nutrient conditions. Further analysis on inorganic elements before and after fermentation showed that specific elements of Mg, Ca, P and S were significantly reduced and could have assisted the fermentation. Based on the results obtained from sap collection, chemical characterization and fermentation, the ethanol potential from nipa planted at a density of 1000 ha^-1 would range from 4550–9100 L ha^-1 y^-1. Conclusively, nipa sap showed some interesting characteristics which makes it a potential feedstock for ethanol production.     

Production of biodiesel from citrus maxima (Chakotara) seed oil,a potential of non-food feedstock and its blends with n butanol-diesel and purification,utilization of glycerol obtained as by-product from biodiesel

The aim of the study is to enhance the production and performance of biodiesel from non-food feedstock seeds of citrus maxima through base catalyzed transesterification process. The Performance of biodiesel was increased by the blends with butanol-diesel (Biodiesel + Butanol + Diesel) in different proportions. The obtained biodiesel and its blends were characterized by ASTM. In this study, Glycerol was obtained as a by-product of citrus maxima biodiesel. Crude glycerol was purified by the H₃PO₄, H₂SO₄, HCl, and HNO₃. The characterization of glycerol included Flash Point, ash Content, alkalinity, FT-IR, etc..     

Feasibility of edible oil vs. non-edible oil vs. waste edible oil as biodiesel feedstock

Biodiesel has high potential as a new and renewable energy source in the future, as a substitution fuel for petroleum-derived diesel and can be used in existing diesel engine without modification. Currently, more than 95% of the world biodiesel is produced from edible oil which is easily available on large scale from the agricultural industry. However, continuous and large-scale production of biodiesel from edible oil without proper planning may cause negative impact to the world, such as depletion of food supply leading to economic imbalance. A possible solution to overcome this problem is to use non-edible oil or waste edible oil (WEO). In this context, the next question that comes in mind would be if the use of non-edible oil overcomes the short-comings of using edible oil. Apart from that, if WEO were to be used, is it sufficient to meet the demand of biodiesel. All these issues will be addressed in this paper by discussing the advantages and disadvantages of using edible oil vs. non-edible vs. WEO as feedstock for biodiesel production. The discussion will cover various aspects ranging from oil composition, oil yield, economics, cultivation requirements, land availability and also the resources availability. Finally, a proposed solution will be presented.     

Effect of natural,accelerated and saturated salt accelerated aging on the Jatropha curcas L. seeds in optimizing the yield of seed oil as feedstock for biodiesel

Uninterrupted and good quality of feedstock is a key factor for biodiesel. Jatropha curcas L. has emerged as a favorite unconventional source of fuel. This paper aims to map the changes in Jatropha curcas L. oil, extracted from seeds subjected to natural aging (NA), accelerated aging (AA) and saturated salt accelerated aging (SSAA) are two methods employed to mimic natural aging. The results depicted that prolonged and intense aging decreased the oil yield and caused deterioration of the oil with a high free fatty acids content, saponification value, peroxide value, and low iodine value. Decrease in oleic acid content is the result of lipid peroxidation due to prolonged storage. However, Jatropha curcas L. seeds subjected to natural aging even up to one year could still serve as the best feedstock because of its resistance towards deteriorative aging effects.     

Organic municipal solid waste (MSW) as feedstock for biodiesel production: A financial feasibility analysis

The pursuit towards an alternative solution to fossil fuel has facilitated science investigation initiatives that compare various options leading to biodiesel production. Besides conventional feedstock derived from vegetable oils, alternative sources that could be produce in large scale at competitive costs are the main scope of research in this field. This paper investigates the financial feasibility using organic solid waste as a feedstock, which results in the production of biodiesel through the conversion of volatile fatty acids into lipids (VFA). As a result, based on existing references of capital and operating costs, production and extraction yields for VFA and lipids and an internal rate of return of 15% in real terms, we concluded that biodiesel production is competitive compared to subsidized biodiesel traded in regions of Europe and the United States. These results encourage research aims to examine this technology at a larger scale. The adoption of public policies for the urban waste's disposal and collection, to reduced municipality's costs associated to the treatment, is also important for the implementation of these technologies.     

Mahua oil (Madhuca Indica seed oil) methyl ester as biodiesel-preparation and emission characterstics

There is an increasing interest in many countries to search for suitable alternative fuels that are environment friendly. Although straight vegetable oils can be used in diesel engines, their high viscosities, low volatilities and poor cold flow properties have led to the investigation of various derivatives. Biodiesel is a fatty acid alkyl ester, which can be derived from any vegetable oil by transesterification. Biodiesel is a renewable, biodegradable and non-toxic fuel. In this study, Mahua oil (Madhuca indica seed oil) was transesterified with methanol using sodium hydroxide as catalyst to obtain mahua oil methyl ester. This biodiesel was tested in a single cylinder, four stroke, direct injection, constant speed, compression ignition diesel engine (Kirloskar) to evaluate the performance and emissions.     

Microalgal biomass as a feedstock for bio-hydrogen production

In the present work, H₂ production from microalgal biomass via dark fermentation was optimized by response surface methodology (RSM). Substrate concentration and initial pH were varied from 3 to 117 g dry cell weight (dcw)/L and 4.2–9.8, respectively. During the fermentation, pH was not controlled. The optimal condition was found at 76 g dcw/L and initial pH of 7.4, under which yielded 31.2 mL H₂/g dcw. The results of ANOVA verify that the relationship between substrate concentration and initial pH was slightly interdependent or significantly interactive. Besides, the monitoring alkalinity and pH during the confirmation test clearly showed that dark fermentative H₂ production (DFHP) from microalgal biomass was feasible without addition of external alkaline owing to the disruption of cell wall, which provided buffer capacity (max. 3800 mg as CaCO₃/L). Therefore, although it involved a batch test, this approach would promote the practical viability of DFHP from microalgal biomass. The main organic acids were acetic and butyric acids which are general metabolites found in successful DFHP.     

Biodiesel from Milo (Thespesia populnea L.) seed oil

There is a need to seek non-conventional seed oil sources for biodiesel production due to issues such as supply and availability as well as food versus fuel. In this context, Milo (Thespesia populnea L.) seed oil was investigated for the first time as a potential non-conventional feedstock for preparation of biodiesel. This is also the first report of a biodiesel fuel produced from a feedstock containing cyclic fatty acids as T. populnea contains 8,9-methylene-8-heptadecenoic (malvalic) and smaller amounts of two cyclopropane fatty acids besides greater amounts of linoleic, oleic and palmitic acids. The crude oil extracted from T. populnea seed was transesterified under standard conditions with sodium methoxide as catalyst. Biodiesel derived from T. populnea seed oil exhibited fuel properties of density 880 kg m⁻³, kinematic viscosity 4.25 mm²/s; cetane number 59.8; flash point 176 °C; cloud point 9 °C; pour point 8 °C; cold filter plugging point 9 °C; sulfur content 11 mg kg⁻¹; water content 150 mg kg⁻¹; ash content 15 mg kg⁻¹; and acid value as KOH 250 mg kg⁻¹. The oxidative stability of 2.91 h would require the use of antioxidants to meet specifications in standards. Generally, most results compared well with ASTM D6751 and EN 14214 specifications.     

Alkaline catalyzed biodiesel production from safflower (Carthamus tinctorius L.) oil: Optimization of parameters and determination of fuel properties

In this study, the process of biodiesel production from safflower oil was optimized using a single-stage alkaline catalyst (NaOH). The optimization process was carried out depending on parameters, such as catalyst concentration, methanol-oil ratio, reaction temperature, and reaction time. The optimum biodiesel conversion efficiency was obtained to be 93.4% at 0.5% catalyst concentration, 20% methanol-oil ratio, 60 min reaction time, and 60°C reaction temperature. The fuel properties of biodiesel obtained under optimal conditions were determined.     

Sweet sorghum as a whole-crop feedstock for ethanol production

The potential of sweet sorghum as an alternative crop for ethanol production was investigated in this study. Initially, the enzymatic hydrolysis of sorghum grains was optimized, and the hydrolysate produced under optimal conditions was used for ethanol production with an industrial strain of Saccharomyces cerevisiae, resulting in an ethanol concentration of 87 g L⁻¹. From the sugary fraction (sweet sorghum juice), 72 g L⁻¹ ethanol was produced. The sweet sorghum bagasse was submitted to acid pretreatment for hemicellulose removal and hydrolysis, and a flocculant strain of Scheffersomyces stipitis was used to evaluate the fermentability of the hemicellulosic hydrolysate. This process yielded an ethanol concentration of 30 g L⁻¹ at 23 h of fermentation. After acid pretreatment, the remaining solid underwent an alkaline extraction for lignin removal. This partially delignified material, known as partially delignified lignin (PDC), was enriched with nutrients in a solid/liquid ratio of 1 g/3.33 mL and subjected to simultaneous saccharification and fermentation (SSF) process, resulting in an ethanol concentration of 85 g L⁻¹ at 21 h of fermentation. Thus, from the conversion of starchy, sugary and lignocellulosic fractions approximately 160 L ethanol.ton⁻¹ sweet sorghum was obtained. This amount corresponds to 13,600 L ethanol.ha⁻¹.     

Optimized alkali-catalyzed transesterification of wild mustard (Brassica juncea L.) seed oil

Biodiesel was developed from a non-edible oil source, i.e., wild mustard (Brassica juncea L) oil through optimized alkali-catalyzed transesterification with methanol using potassium hydroxide as a catalyst. Biodiesel yield of (95.54 % with 96.72 % w/w ester content) was obtained under optimal conditions of 0.75 % KOH w/w of oil, 6:1 methanol to oil molar ratio, 60°C temperature, and a duration of 45 min. Properties of wild mustard (Brassica juncea L) oil biodiesel were determined and found to be within the limits of ASTM D6751 specifications. As a result, wild mustard (Brassica juncea L), as an agricultural crop, might be a reasonable feedstock for biodiesel production.