Biofuel Candidate Research Articles

Ionic Liquids Mediated One‐Pot Synthesis of Second Generation 5‐Ethoxymethylfurfural (5‐EMF); A Potent Biofuel Candidate

Abstract5‐Ethoxymethylfurfural (5‐EMF) is a promising fuel alternative and biofuel additive due to its high energy potential. Principal method for its synthesis is etherification of hydroxyl group of 5‐hydroxymethylfurfural (5‐HMF), produced by the dehydration of fructose. Currently existing methods for the synthesis of 5‐EMF are not industrially feasible due to the issues associated with their starting materials; either they are highly expensive (such as 5‐HMF), or compete with food (sugars such as fructose and glucose). Herein, we are reporting a one‐pot protocol for the synthesis of 5‐EMF using non‐food indigenous agricultural waste material, thus completely eliminating the both issues. Cost is also very much reduced due to the utilization of cheap pyridinium based ionic liquids. Energy, time and solvents use is also reduced, as reaction is happening in a single pot. The process is optimized first for fructose (73 % 5‐EMF yield) and glucose (16 % 5‐EMF), and was then extended for real biopolymeric cellulose (16 % 5‐EMF) and wheat husk biomass (15 % 5‐EMF). Product was characterized via HPLC and 1HNMR spectroscopy.

Tunnel Shape of Aldehyde Deformylating Oxygenase Determines Length of Alkane Products

R&D on renewable energy has gained the centre stage again due to renewed call to tackle climate change. In this effort, drop‐in fuels like alkane will be the main biofuel candidate since they are similar to the petroleum fuel in their chemical and physical properties. Cyanobacterial AAR (acyl‐ACP reductase) ‐ ADO (aldehyde deformylating oxygenase) pathway, which converts fatty acyl‐ACP intermediate of the fatty acid synthesis cycle into alkane/alkene via an aldehyde intermediate, was the first pathway discovered for the microbial production of hydrocarbon. We have earlier reported an engineered thermostable ADO and demonstrated metabolic modelling based pathway engineering in E. coli to produce highest alkane titer reported so far. We have further performed biochemical characterization of ADOs from three different cyanobacteria (Nostoc punctiformes, Oscillatoria jasorensis, Oscillatoria sp CCC305), and found out that ADO from N. punctiforme(NpADO) yielded maximum alkane titer, with preference towards C12‐chain length aldehyde substrate. Upon structural modelling and molecular dynamics (MD) simulation, it was found that NpADO has suitable tunnel shape and size to facilitate catalysis of C12‐chain substrate. Considering the importance of the catalytic products in the aviation fuel range, we attempted to further improve the product specificity by mutating residues in the main tunnel to facilitate fitting of C12‐chain substrate in the cavity and blocking other less favorable tunnel. The engineered ADO showed 2‐fold higher catalytic activity towards C12‐chain aldehyde. MD simulations of the engineered ADOs indicated favorable tunnel structure, stabilized ADO‐substrate interactions and enhanced interaction of substrate with the di‐iron centre. These findings suggest ADO tunnels play a critical role in defining their substrate specificity and catalysis.

Highly basic and active ZnO–x% K2O nanocomposite catalysts for the production of methyl ethyl ketone biofuel

AbstractHerein we demonstrate the preparation and characterization of nanocrystalline ZnO, either pure or promoted with 1–10 wt.% K2O. All catalysts calcined at 400°C were in the nano‐crystallite scale as confirmed by X‐ray powder diffraction analysis in the 22.9–28.0 nm range. According to the CO2‐temperature‐programmed desorption study using thermogravimetric analysis and differential scanning calorimetry techniques, they have a broad spectrum of surface basic sites. Because of the significance of methyl ethyl ketone (MEK) as a next‐generation biofuel candidate with high‐octane, low boiling point, and relatively high vapor pressure. The prepared catalysts were examined during the direct production of MEK via 2‐butanol (2B) dehydrogenation. Among catalysts tested, ZnO promoted with 1% K2O showed a superior catalytic activity towards the conversion of 2B to MEK, that is, 71.7% at a reaction temperature of 275°C. The selectivity for the production of MEK over all catalysts was ≥95% across all catalysts when using N2‐gas as a carrier. The use of airflow in this reaction resulted in a clear loss of selectivity toward MEK production as well as the appearance of undesirable products such as acetone and methanol. All catalytic properties of catalysts, particularly those of moderate strength, were highly correlated with the distribution of surface basic sites. Finally, a reaction mechanism was proposed for the dehydrogenation of 2B, followed by the partial oxidation of MEK.

Performance and Emission Characteristics of Diesel Engine Using Ether Additives: A Review

Pressure on alternative fuels and strict environmental regulations are driving a strategic shift in the efficient use of renewable biofuels. One of the promising biofuel candidates recently interested by scholars is a biological or organic additive that is added into diesel or biodiesel fuel to improve engine performance and reduce pollutant emissions. With efforts to improve efficiency and combustion quality in cylinders, combustion characteristics, flame structure and emission formation mechanism in compression ignition (CI) engines using blended fuel with organic additives have been studied on the effect of additive properties on the combustion behaviour. In this review, the physicochemical properties of typical organic additives such as ethers compounds and their effects on engine performance and emission characteristics have been discussed and evaluated based on conclusions of recent relevant literature. The results of the analysis revealed the prospect of using ether additives to improve combustion in cylinders and reduce pollutant emissions from CI engines. Obviously, the presence of higher oxygen content, lower viscosity and density, and higher cetane number resulted in a positive change in the combustion dynamics as well as a chain of mechanisms for the formation of pollutant precursors in the cylinder. Therefore, ether additives have a significant contribution to the sustainable energy strategy of the transportation sector in the next period when internal combustion engines still dominate in the competition for energy system choices equipped on vehicles.

Laminar burning velocity and cellular instability of 2-butanone-air flames at elevated pressures

2-butanone has been exploited as a promising next-generation biofuel candidate for its impressive knock resistant properties. However, its combustion characteristics and intrinsic instabilities have not been well explored. In this study, an experimental and theoretical investigation on laminar burning velocity (LBV) and onset of flame instability in spherically expanding flames of 2-butanone-air mixtures was conducted in a constant-volume chamber at temperature of 423 K, pressure of 1–8 bar, and equivalence ratio ϕ of 0.7–1.5. The measured LBVs and Markstein lengths of 2-butanone were observed to decrease noticeably as the pressure increased. Four recently established kinetic models were applied to predict the experimental data. Stability analysis was performed to investigate the effect of pressure and ϕ on the onset of the cellular instability of 2-butanone flames. Results showed that the hydrodynamic instability monotonically increased as pressure increased and non-monotonically varied with increasing ϕ. Thermal-diffusive instability increased dramatically as ϕ increased while showed less sensitivity to the variation in pressure. The critical conditions at which the flame status turn stable into unstable were also evaluated. The critical Peclet number decreased monotonically as ϕ increased, illustrating that fuel-rich flames suffer more severe cellular instability than fuel-lean flames. The critical flame radius decreased as pressure increased in both experimental measurements and theoretical calculations, reflecting that the onset of cellular instabilities of 2-butanone-air mixtures advanced to smaller radius at higher initial pressures.

Tolerance to Allelopathic Inhibition by Free Fatty Acids in Five Biofuel Candidate Microalgae Strains

Tolerance to Allelopathic Inhibition by Free Fatty Acids in Five Biofuel Candidate Microalgae Strains

Analysis of Swamp Microalgal Isolates from South Sumatra as Biofuel Candidates

Microalgal isolates in various habitats have different biocomponents, and isolates found in the swamps of South Sumatra have not been explored deeply. This study was designed to analyse morphologically and isolate microalgae that have potential as biofuel candidates through their lipid content. Results showed that five isolates originating from four different sources in South Sumatra, namely, Chlorella vulgaris Beyerinck (DV 005), Dictyosphaerium granulatum Hindák (DV 003), Nannochloropsis sp. (DV 009), Scenedesmus bernardii G. M. Smith (DV 011) and Golenkinia radiata Chodat (DV 001), were identified. Amongs the five isolates, the C. vulgaris Beyerinck (DV 005) isolate had the highest lipid content (15.30%), indicating its potential as biofuel candidate.

Fatty Acids Derivatives From Eukaryotic Microalgae, Pathways and Potential Applications.

The exploitation of petrochemical hydrocarbons is compromising ecosystem and human health and biotechnological research is increasingly focusing on sustainable materials from plants and, to a lesser extent, microalgae. Fatty acid derivatives include, among others, oxylipins, hydroxy fatty acids, diols, alkenones, and wax esters. They can occur as storage lipids or cell wall components and possess, in some cases, striking cosmeceutical, pharmaceutical, and nutraceutical properties. In addition, long chain (>20) fatty acid derivatives mostly contain highly reduced methylenic carbons and exhibit a combustion enthalpy higher than that of C14–20 fatty acids, being potentially suitable as biofuel candidates. Finally, being the building blocks of cell wall components, some fatty acid derivatives might also be used as starters for the industrial synthesis of different polymers. Within this context, microalgae can be a promising source of fatty acid derivatives and, in contrast with terrestrial plants, do not require arable land neither clean water for their growth. Microalgal mass culturing for the extraction and the exploitation of fatty acid derivatives, along with products that are relevant in nutraceutics (e.g., polyunsaturated fatty acids), might contribute in increasing the viability of microalgal biotechnologies. This review explores fatty acids derivatives from microalgae with applications in the field of renewable energies, biomaterials and pharmaceuticals. Nannochloropsis spp. (Eustigmatophyceae, Heterokontophyta) are particularly interesting for biotechnological applications since they grow at faster rates than many other species and possess hydroxy fatty acids and aliphatic cell wall polymers.

Studies on Zero-cost algae based phytoremediation of dye and heavy metal from simulated wastewater

In the present study, filamentous algae, an emerging candidate for biofuel and other useful chemical production, has been investigated as a biological adsorbent for the removal of contaminants from synthetic wastewater. Operational parameters were optimized in batch phytoremediation experiments. The adsorption equilibrium isotherm models such as Langmuir, Freundlich, and Dubinin-Radushkevitch and kinetics models such as pseudo-1st and pseudo-2nd order in methylene blue decolorization and Cr(VI) removal were also investigated. The D-R isotherm theory provided the best fit. The pseudo-2nd order model accurately described the adsorption kinetic data. Maximum adsorption capacities were observed to 5.03 mg.g−1 and 0.77 mg.g−1 along with removal efficiencies were achieved to 91.3% and 91.4% for methylene blue and Cr(VI) remediation, respectively. Moreover, intra-particle diffusion kinetic theory was used to describe the mechanism. These outcomes are significant in the development of algae-based zero-cost pollutants removal technology in wastewater treatment.

A novel microalgal biofilm reactor using walnut shell as substratum for microalgae biofilm cultivation and lipid accumulation

Microalgae are a potential candidate for biofuels, but the high cost and low biomass yield hinder the scale-up application of microalgae. In this study, a novel walnut shell based self-permeating biofilm reactor (WSPBR) was proposed for cultivation of Chlorella vulgaris (C. vulgaris) and Scenedesmus obliquus (S. obliquus). Major influencing factors such as walnut shell size, light intensity and CO2 concentration were studied in detail. The results showed that CO2 can enhance the storage of metabolic products in microalgal cells. Thermodynamics analysis indicated that C. vulgaris and S. obliquus were likely to adhere on the surface of walnut shells. S. obliquus and C. vulgaris biomass reached the maximum values of 97.43 and 70.49 g m−2, respectively, corresponding to the walnut shell size of 0.8–1.2 mm, light intensity of 150 μmol m−2 s−1 and CO2 concentration of 2%. The lipid contents of these microalgal cells were 34.32% and 28.94%, respectively. These results indicated that WSPBR was an efficient system for microalgae cultivation as feedstock for biofuels.

Experimental and kinetic modeling studies of di-n-propyl ether pyrolysis at low and atmospheric pressures

The pyrolysis of di-n-propyl ether (DPE), a potential biofuel candidate, was studied under a temperature range of 850–1350 K in a flow reactor at low and atmospheric pressures. Synchrotron vacuum ultraviolet photoionization mass spectrometry was used for isomeric identification and mole fraction measurements of the pyrolysis products, especially the free radicals. Specific products were observed and measured for the unimolecular decomposition reactions of DPE. A detailed kinetic model of DPE pyrolysis was developed based on the n-propanol combustion model. Modeling analyses including the rate of production (ROP) and sensitivity analyses were performed to reveal the consumption pathways of DPE, as well as the formation and consumption pathways of intermediates and products. ROP and sensitivity analyses indicated that the consumption reaction of DPE was mainly controlled by the unimolecular decomposition reactions and H-abstractions at both low and atmospheric pressures. The pericyclic reaction, leading to n-propanol + propylene, was the most important unimolecular decomposition reactions, especially at low pressure. The H-abstraction reactions of DPE played crucial roles in its consumption. Further β-C–C and β-C–O scission reactions of the three primary radicals can produce some oxygenated and hydrocarbon products. Relatively high mole fractions of C1–C3 aldehydes and C1–C3 alkane, alkene, and alkyl radicals were observed, which demonstrated the structural feature of DPE. Comparison of the product distribution between DPE and n-propanol were also analyzed.

Fast pyrolysis of pitch pine biomass in a bubbling fluidized-bed reactor for bio-oil production

The kinetic parameters for the pyrolysis of biomass of the pitch pine (Rigida pine P. Mill) were examined by thermogravimetric analysis in the temperature range 25°C to 700°C, in which the main decomposition was occurred from 250°C to 400°C. Pyrolysis of pitch pine has been investigated in a bubbling fluidized bed reactor. In this system, silica sand and nitrogen were used as the fluidizing bed material and fluidizing medium, respectively. The experimental was systemically performed on different temperature, fluidized velocity, and particle size of biomass. The optimum temperature condition at which the bio-oil yields reached the highest value (65.5%) was 500°C. In addition, the higher heating values of bio-oils from pitch pine biomass were reached in the range 22MJ/kg to 24MJ/kg. Moreover, this bio-oil had high content of useful chemicals including such as levoglucosan, furfural, and guaiacol. The large amount of C5–C11 (gasoline fraction) produced make the pyrolyzed oil originating from pitch pine trees a promising biofuel candidate.

A method of wet algal lipid recovery for biofuel production

Drying of algae is resource-intensive (land, energy) for biofuel production. A method to recover lipids from wet algae has been developed at lab scale. The method is based on introduction of polar solvent first into wet algae to replace the water inside the cells, followed by gradual introduction of non-polar solvent to replace the polar solvent and thus extract lipids. Extraction conditions are normal temperature and pressure (25 °C; 1 atm). Dunaliella tertiolecta was adopted for extraction due to its potential as promising biofuel candidate and non-requirement of pretreatment before extraction. 1 g of wet algal paste was treated with polar solvent, polar solvent: non-polar solvent mixture (1:1 volume ratio) and non-polar solvent in series. Solvents were added in 3 steps for each solvent type and at 3 times the volume of the algal paste at each step. Mixing time was 30 s for each step. 2-propanol/hexane was preferred as viable solvent system and methanol/methyl t-butyl ether was also found to be effective. Lipid recovery matched that of analytical method. Other reported methods for wet algal lipid recovery usually employ more intensive conditions or long extraction times. Classification of neutral lipids and polar lipids in total lipids extracted by the method (68:31% by weight) was similar to that of the analytical method. It was also found that sun drying and any similar prolonged wet state of harvested algae may lead to significant loss of lipids, stressing the need for immediate processing as in the case of wet algal lipid extraction.

Ignition delay times of methane/diethyl ether (DEE) blends measured in a rapid compression machine (RCM)

Diethyl ether (DEE) is an interesting species for combustion for at least two reasons: On the one hand, it is used as a kind of ”worst case” reference substance for studies concerned with the prevention of accidental ignition events. On the other hand, it is also a candidate bio-fuel. For this reason, in this work, auto-ignition of two different ▪ /DEE-mixtures (90/10 and 95/5 mol-% ▪ /DEE) are studied in a rapid compression machine (RCM). In the RCM, the gas mixture is compressed in a piston–cylinder device up to 20bar and held under isochoric conditions at top dead center. Auto-ignition occurs after an ignition delay time (IDT). IDTs are measured for compression temperatures ranging between 515 and 925K, for both, stoichiometric and fuel-rich mixtures (equivalence ratio ϕ=2). The experimental data are compared to results of simulations involving detailed chemistry, as well as to other fuels investigated in the same RCM (results from literature).

Characterization of biomass produced by Candida tropicalis ASY2 grown using sago processing wastewater for bioenergy applications and its fuel properties

The cost of biodiesel production and the requirement of raw ingredients are the primary constraints that need to be addressed while searching for viable alternative fuels to petrol and diesel. Oleaginous yeasts are gaining wider acceptance as biofuel candidates among oil-rich crops/microbes. The present investigation aimed to integrate the agro-industrial wastewater stream as a nutrient source for the cultivation of oleaginous yeast and to use the resultant biomass and lipid as a feedstock for biofuel synthesis. The yeast biomass grown in sago processing wastewater contained 7.21% moisture content, 69.01% volatile matter, 12.61% fixed carbon, and 11.16% ash content. The ultimate analysis determined the contents of carbon (40.43%), nitrogen (5.14%), hydrogen (4.62%), sulfur (0.54%), and oxygen (49.27%). The heating value of yeast biomass was 16.54 MJ kg−1. The thermal behavior of yeast biomass also suggests its potential use as an energy source. The FTIR spectrum of biomass had major lipid (3030–2800 cm−1 and 1500–1350 cm−1) and carbohydrate (1250 cm−1 and 1000 cm−1) functional peaks. Further FAME profiling revealed that the yeast biomass is primarily composed of stearic, oleic, linoleic, and linolenic acids, similar to the vegetable oils. The fuel characteristics of yeast biodiesel (SV, 168.87 mg KOH g−1; IV, 120 mg I2 100 g−1; CN, 61.79; and KV, 3.16 mm2 s−1) are also within the ASTM standard limits, suggesting that yeast biomass could be a sustainable and economically viable feedstock for both solid and liquid biofuel production.

Bioprospecting microalgae harnessed from the coastal belt of Mangalore, India as prospective nutraceutical and biofuel candidates

ABSTRACT The nature of global dietary supplements is transitioning from animal derivatives to plant based. Industries around the world are seeking vegan alternatives to animal-derived supplements. The microalgal industry is expected to undergo a market boom in the current decade. Microalgal supplements (power based and extracts) as well as microalgal fuels are expected to show a significant increase in market value. Microalgae are an under-utilized source of high-value products. They are rich reservoirs of multiple compounds capable of enhancing immunity, fortifying nutritional diets and improving cardiovascular health. Microalgae are also high lipid producing organisms, which make them viable candidates in the global search for energy alternatives. However, the inability to translate in vitro results onto the industrial scale is a major drawback of the microalgal research landscape. It is therefore, vital to find a robust microalgal species capable of producing a feasible quantity of high-value compounds. This paper investigates the potential of four microalgae sourced from the coastal town of Mangalore, India as candidates for nutraceutical industries and the clean energy industry. Desmodesmus komareikii (MK990101) was found to be rich in total lipid, while the three Chlorella species were found to be relatively richer in total protein yields. Chlorella thermophila (MN006612) is capable of yielding harvests up to nearly 280 tonnes/acre/year. Chlorella thermophila (MN006612) yielded the highest amount of both mono and polyunsaturated fatty acids. The fatty acid profiles of Chlorella thermophila (MN006612), Chlorella vulgaris (MN252517-18) and Chlorella sorokiniana (MN011568) can be explored as an alternative edible oil. Desmodesmus komareikii (MK990101) yielded the highest amount of saturated fatty acids, which are used in the production of clean and quality biofuels.

Elucidating the differences in oxidation of high-performance \u03b1- and \u03b2- diisobutylene biofuels via Synchrotron photoionization mass spectrometry

Biofuels are a promising ecologically viable and renewable alternative to petroleum fuels, with the potential to reduce net greenhouse gas emissions. However, biomass sourced fuels are often produced as blends of hydrocarbons and their oxygenates. Such blending complicates the implementation of these fuels in combustion applications. Variations in a biofuel’s composition will dictate combustion properties such as auto ignition temperature, reaction delay time, and reaction pathways. A handful of novel drop-in replacement biofuels for conventional transportation fuels have recently been down selected from a list of over 10,000 potential candidates as part of the U.S. Department of Energy’s (DOE) Co-Optimization of Fuels and Engines (Co-Optima) initiative. Diisobutylene (DIB) is one such high-performing hydrocarbon which can readily be produced from the dehydration and dimerization of isobutanol, produced from the fermentation of biomass-derived sugars. The two most common isomers realized, from this process, are 2,4,4-trimethyl-1-pentene (α-DIB) and 2,4,4-trimethyl-2-pentene (β-DIB). Due to a difference in olefinic bond location, the α- and β- isomer exhibit dramatically different ignition temperatures at constant pressure and equivalence ratio. This may be attributed to different fragmentation pathways enabled by allylic versus vinylic carbons. For optimal implementation of these biofuel candidates, explicit identification of the intermediates formed during the combustion of each of the isomers is needed. To investigate the combustion pathways of these molecules, tunable vacuum ultraviolet (VUV) light (in the range 8.1–11.0 eV) available at the Lawrence Berkeley National Laboratory’s Advanced Light Source (ALS) has been used in conjunction with a jet stirred reactor (JSR) and time-of-flight mass spectrometry to probe intermediates formed. Relative intensity curves for intermediate mass fragments produced during this process were obtained. Several important unique intermediates were identified at the lowest observable combustion temperature with static pressure of 93,325 Pa and for 1.5 s residence time. As this relatively short residence time is just after ignition, this study is targeted at the fuels’ ignition events. Ignition characteristics for both isomers were found to be strongly dependent on the kinetics of C4 and C7 fragment production and decomposition, with the tert-butyl radical as a key intermediate species. However, the ignition of α-DIB exhibited larger concentrations of C4 compounds over C7, while the reverse was true for β-DIB. These identified species will allow for enhanced engineering modeling of fuel blending and engine design.

A Perspective on Biofuels Use and CCS for GHG Mitigation in the Marine Sector.

SummaryThe greenhouse gas (GHG) emissions of the marine sector were around 2.6% of world GHG emissions in 2015 and are expected to increase 50%–250% to 2050 under a “business as usual” scenario, making the decarbonization of this fossil fuel-intensive sector an urgent priority. Biofuels, which come in various forms, are one of the most promising options to replace existing marine fuels for accomplishing this in the short to medium term. Some unique challenges, however, impede biofuels penetration in the shipping sector, including the low cost of the existing fuels, the extensive present-day refueling infrastructure, and the exclusion of the sector from the Paris climate agreement. To address this, it is necessary to first identify those biofuels best suited for deployment as marine fuel. In this work, the long list of possible biofuel candidates has been narrowed down to four high-potential options—bio-methanol, bio-dimethyl ether, bio-liquefied natural gas, and bio-oil. These options are further evaluated based on six criteria—cost, potential availability, present technology status, GHG mitigation potential, infrastructure compatibility, and carbon capture and storage (CCS) compatibility—via both an extensive literature review and stakeholder discussions. These four candidates turn out to be relatively evenly matched overall, but each possesses certain strengths and shortcomings that could favor that fuel under specific circumstances, such as if compatibility with existing shipping infrastructure or with CCS deployment become pivotal requirements. Furthermore, we pay particular attention to the possibility of integrating deployment of these biofuels with CCS to further reduce marine sector emissions. It is shown that this aspect is presently not on the radar of the industry stakeholders but is likely to grow in importance as CCS acceptability increases in the broader green energy sector.

Flame Characteristics and Ignition Delay Times of 2,5-Dimethylfuran: A Systematic Review With Comparative Analysis

Abstract Global concerns about CO2 levels in the atmosphere, energy security, and the depletion of fossil fuel supply have been the key motivation to develop bio-based fuel resources, which leads to promising and potential strategies of renewable and carbon-neutral biofuels. Among biofuels being strongly developed, 2,5-dimethylfuran (DMF) is a new alternative biofuel candidate since DMF could be synthesized from available and durable lignocellulosic biomass, as well as DMF's physicochemical properties were found to be similar to those of fossil fuels. Therefore, the comprehensive investigation on DMF is very essential before putting DMF into the commercial scale and the engine application. In this current work, the temporal evolutions of laminar flame characteristics including laminar burning velocities, unstretched flame propagation speed, and Schlieren images were critically reviewed based on the comparison of DMF with other fuels. Besides, flame instabilities were also evaluated in detail. Finally, ignition delay times were thoroughly analyzed with the variation of the initial parameters such as temperature, pressure, and equivalent ratio, suggesting that DMF could become the potential fuel for the spark ignition engine. In the future, the experimental studies on the real engines fueled with DMF should be carefully and completely performed to have a comprehensive evaluation of this promising biofuel class.

Green toxicological investigation for biofuel candidates

To avoid potential risks of biofuels on the environment and human, ecotoxicity investigation should be integrated into the early design stage for promising biofuel candidates. In the present study, a green toxicology testing strategy combining experimental bioassays with in silico tools was established to investigate the potential ecotoxicity of biofuel candidates. Experimental results obtained from the acute immobilisation test, the fish embryo acute toxicity test and the in vitro micronucleus assay (Chinese hamster lung fibroblast cell line V79) were compared with model prediction results by ECOSAR and OECD QSAR Toolbox. Both our experimental and model prediction results showed that 1-Octanol (1-Oct) and Di-n-butyl ether (DNBE) were the most toxic to Daphnia magna and zebrafish among all the biofuel candidates we investigated, while Methyl ethyl ketone (MEK), Dimethoxymethane (DMM) and Diethoxymethane (DEM) were the least toxic. Moreover, both in vitro micronucleus assay and OECD QSAR Toolbox evaluation suggested that the metabolites present higher genotoxicity than biofuel candidates themselves. Overall, our results proved that this green toxicology testing strategy is a useful tool for assessing ecotoxicity of biofuel candidates.