High Quality Biodiesel Production Research Articles

Co-culturing Chlorella minutissima with Escherichia coli can increase neutral lipid production and improve biodiesel quality.

Lipid productivity and fatty acid composition are important metrics for the production of high quality biodiesel from algae. Our previous results showed that co-culturing the green alga Chlorella minutissima with Escherichia coli under high-substrate mixotrophic conditions enhanced both culture growth and crude lipid content. To investigate further, we analyzed neutral lipid content and fatty acid content and composition of axenic cultures and co-cultures produced under autotrophic and mixotrophic conditions. We found that co-culturing C. minutissima with E. coli under high substrate conditions (10 g/L) increased neutral lipid content 1.9- to 3.1-fold and fatty acid content 1.5- to 2.6-fold compared to equivalent axenic C. minutissima cultures. These same co-cultures also exhibited a significant fatty acid shift away from trienoic and toward monoenoic fatty acids thereby improving the quality of the synthesized fatty acids for biodiesel production. Further investigation suggested that E. coli facilitates substrate uptake by the algae and that the resulting growth enhancement induces a nitrogen-limited condition. Enhanced carbon uptake coupled with nitrogen limitation is the likely cause of the observed neutral lipid accumulation and fatty acid profile changes.

Cultivation of Chlorella sp. using raw dairy wastewater for nutrient removal and biodiesel production: Characteristics comparison of indoor bench-scale and outdoor pilot-scale cultures

The biomass productivity and nutrient removal capacity of simultaneous Chlorella sp. cultivation for biodiesel production and nutrient removal in raw dairy wastewater (RDW) in indoor bench-scale and outdoor pilot-scale photobioreactors were compared. Results from the current work show that maximum biomass productivity in indoor bench-scale cultures can reach 260mgL−1day−1, compared to that of 110mgL−1day−1 in outdoor pilot-scale cultures. Maximum chemical oxygen demand (COD), total nitrogen (TN), and total phosphorous (TP) removal rate obtained in indoor conditions was 88.38, 38.34, and 2.03mgL−1day−1, respectively, this compared to 41.31, 6.58, and 2.74mgL−1day−1, respectively, for outdoor conditions. Finally, dominant fatty acids determined to be C16/C18 in outdoor pilot-scale cultures indicated great potential for scale up of Chlorella sp. cultivation in RDW for high quality biodiesel production coupling with RDW treatment.

Designing of a “cheap to run” fermentation platform for an enhanced production of single cell oil from Yarrowia lipolytica DSM3286 as a potential feedstock for biodiesel

In this study, the culture medium components screening and filtering were undertaken in order to set up efficient and cost effective minimal culture media for lipid production from Yarrowia lipolytica DSM3286. The basal minimal culture medium (S2) designed yielded lipid content up to 35% of the microbial dry cell weight. A set of fermentation strategies based on this minimal medium was developed and the lipid content was raised to 51%. The scale-up under different fermentation conditions based on S2 medium led to a maximum lipid content of 65%. The produced microbial oils displayed interesting properties to be used as a feedstock for high quality biodiesel production. The minimal media and operable cultivation strategies devised in this study, in association with the works done so far by other authors, could enable fast, massive, viable and more economical production of single cell oils and smooth biodiesel manufacture.

Fast Synthesis of High Quality Biodiesel from ‘Waste Fish Oil’ by Single Step Transesterification

A large volume of fish wastes is produced on a daily basis in the Indian sub-continent. This abundant waste source could serve as an economic feedstock for bioenergy generation. In the present study, oil extracted from discarded fish parts was used for high quality biodiesel production. More specifically, a single step transesterification of ‘waste fishoil’ with methanol using sodium methoxide (CH3ONa) as homogeneous catalyst under moderate operational conditions resulted in highly pure biodiesel of > 98% of fatty acid methyl ester (FAME) content. Characterization was performed by Fourier Transform-Nuclear Magnetic Resonance (FT-NMR).

Production of high quality biodiesel from waste acid oil obtained during edible oil refining using ion-exchange resin catalysts

This study was aimed at the continuous production of high quality biodiesel fuel, which fully satisfies international specifications, from waste acid oil with free fatty acids (FFA) content of >95wt%. First, the effect of water on the esterification of FFA with the cation-exchange resin catalyst was discussed. Then, a simple method for pretreating the resin without drying, only supplying alcohol of 1.5cm3/g (wet resin), was proposed. Second, the operating conditions for the continuous esterification of FFA to biodiesel were established. The complete conversion of FFA was achieved at the mole ratio of alcohol:fatty acid residue of 2:1 and sufficient residence time. Subsequent processing with an anion-exchange resin catalyst for the transesterification of triglycerides in the oil was necessary to produce high quality biodiesel. The biodiesel productivity with acid oil was about 8.5 times higher than that with triglyceride-rich oil. This process demonstrated a commercially feasible route to high quality biodiesel.

High performance catalytic distillation using CNTs-based holistic catalyst for production of high quality biodiesel

For production of biodiesel from bio oils by heterogeneous catalysis, high performance catalysts of transesterification and the further utilization of glycerol have been the two points of research. The process seemed easy, however, has never been well established. Here we report a novel design of catalytic distillation using hierachically integrated CNTs-based holistic catalyst to figure out the two points in one process, which shows high performance both for the conversion of bio oils to biodiesel and, unexpectedly, for the conversion of glycerol to more valuable chemicals at the same time. The method, with integration of nano, meso to macro reactor, has overwhelming advantages over common technologies using liquid acids or bases to catalyze the reactions, which suffer from the high cost of separation and unsolved utilization of glycerol.

Monoglycerides reduction in rapeseed oil transesterification for production of high quality biodiesel

Monoglycerides are intermediate by products in rapeseed oil transesterification. If they are present in the bio-fuel and the bio-fuel is used in vehicles, then they can form crystal at cold climate and block fuel injection system of the vehicles. To solve this problem kinetic study of transesterification of rapeseed oil has been carried out in this study. The process variables such as reaction time, temperature, agitation speed and molar ratio of methanol to oil have been optimised to achieve a reduced level of monoglycerides formation in a batch reactor. These information have been integrated into flow through industrial scale transesterification process. Industrial processes demonstrated a steady performance with reduced level of monoglycerides. Monoglycerides level have been reduced to 0.27% (w/w) using 9:1 molar ratio of methanol to oil in about 40 min reaction time. KOH was used as a catalyst to influence transesterification. Results from this study will be helpful to reduce monoglycerides in the industrial scale transesterification process.

Simultaneous production of high quality biodiesel and glycerin from Jatropha oil using ion-exchange resins as catalysts and adsorbent

The simultaneous production of high quality biodiesel and glycerin was realized by a bench-scale process using expanded-bed reactors packed with cation- and anion-exchange resins. The mixed-solution of crude Jatropha oil and methanol at a stoichiometric molar ratio was supplied to the process. The free fatty acid as well as triglyceride was completely converted to biodiesel. All by-products were adsorbed on the resin and the effluent from the process was free from them. The effluent fully met the international biodiesel standard specifications without any downstream purification processes except for removing methanol. The glycerin adsorbed on the resin was completely recovered as a transparent methanol solution during regeneration of the resin.

Scenedesmus incrassatulus CLHE-Si01: A potential source of renewable lipid for high quality biodiesel production

The potential of microalgal oil from Scenedesmus incrassatulus as a feedstock for biodiesel production was studied. Cell concentration of S. incrassatulus and lipid content obtained during mixotrophic growth were 1.8 g/L and 19.5 ± 1.5% dry cell weight, respectively. The major components of biodiesel obtained from S. incrassatulus oil were methyl palmitate (26%) and methyl linoleate (49%), which provided a strong indication of high quality biodiesel. Fuel properties were determined by empirical equations and found to be within the limits of biodiesel standard ASTM D6751 and EN 14214. The quality properties of the biodiesel were high cetane number (62), low density (803 kg/m(3)), low viscosity (3.78 mm(2)/s), oxidation stability (9h) and cold filter plugging point (-4°C). Hence, S. incrassatulus has potential as a feedstock for the production of excellent quality biodiesel.

Comparison of ecological footprint for biobased PHA production from animal residues utilizing different energy resources

Realizing a sustainable development of our planet requires a reduction of waste production, harmful emissions, and higher energy efficiency as well as utilization of renewable energy sources. One pathway to this end is the design of sustainable biorefinery concepts. Utilizing waste streams as raw material is gaining great importance in this respect. This reduces environmental burden and may at the same time contribute to economic performance of biorefineries. This paper investigates the utilization of slaughtering waste to produce biodegradable polyesters, polyhydroxyalkanoates (PHA), via bioconversion. PHA are the target product while production of high quality biodiesel along with meat and bone meal (MBM) as by-products improves the economic performance of the process. The paper focuses on ecological comparison of different production scenarios and the effect of geographical location of production plants taking different energy production technologies and resources into account; ecological footprint evaluation using Sustainable Process Index methodology was applied. Keeping in mind that the carbon source for PHA production is produced from waste by energy intensive rendering process, the effect of available energy mixes in different countries becomes significant. Ecological footprint results from the current study show a bandwidth from 372,950 to 956,060 m2/t PHA production, depending on the energy mix used in the process which is compared to 2,508,409 m2/t for low density polyethylene.

Effect of nitrate on lipid production by T. suecica, M. contortum, and C. minutissima

Abstract Microalgae are an alternative and sustainable source of lipids that can be used as a feedstock for biodiesel production. Nitrate is a good nitrogen source for many microalgae and affects biomass and lipid yields of microalgae. In this study, the effect of nitrate on cell growth and lipid production and composition in Monoraphidium contortum, Tetraselmis suecica, and Chlorella minutissima was investigated. Nitrate affected the production of biomass and the production and composition of lipids of the three microalgae tested. Increasing the nitrate concentration in the culture medium resulted in increased biomass production and higher biomass productivity. Furthermore, increasing the nitrate concentration resulted in a reduction in lipid content and productivity in M. contortum; however, the opposite effect was observed in T. suecica and C. minutissima cultures. C. minutissima and M. contortum lipids contain high levels of oleic acid, with values ranging from 26 to 45.7% and 36.4 to 40.1%, respectively. The data suggest that because of its high lipid productivity (13.79 mg L−1 d−1) and high oleic acid productivity (3.78 mg L−1 d−1), Chlorella minutissima is a potential candidate for the production of high quality biodiesel.

Enhanced mixotrophic growth of microalga Chlorella sp. on pretreated swine manure for simultaneous biofuel feedstock production and nutrient removal

The objectives were to assess the feasibility of using fermented liquid swine manure (LSM) as nutrient supplement for cultivation of Chlorella sp. UMN271, a locally isolated facultative heterotrophic strain, and to evaluate the nutrient removal efficiencies by alga compared with those from the conventionally decomposed LSM–algae system. The results showed that addition of 0.1% (v/v) acetic, propionic and butyric acids, respectively, could promote algal growth, enhance nutrient removal efficiencies and improve total lipids productivities during a 7-day batch cultivation. Similar results were observed when the acidogenic fermentation was applied to the sterilized and raw digested LSM rich in volatile fatty acids (VFAs). High algal growth rate (0.90d−1) and fatty acid content (10.93% of the dry weight) were observed for the raw VFA-enriched manure sample. Finally, the fatty acid profile analyses showed that Chlorella sp. grown on acidogenically digested manure could be used as a feedstock for high-quality biodiesel production.

Characterization of biofilm-forming cyanobacteria for biomass and lipid production

This work reports on one of the first attempts to use biofilm-forming cyanobacteria for biomass and lipid production. Three isolates of filamentous cyanobacteria were obtained from biofilms at different Italian sites and characterized by a polyphasic approach, involving microscopic observations, ecology and genetic diversity (studying the 16S rRNA gene). The isolates were grown in batch systems and in a semi-continuous flow incubator, specifically designed for biofilms development. Culture system affected biomass and lipid production, but did not influence the fatty acid profile. The composition of fatty acids was mainly palmitic acid (>50%) and less amounts of other saturated and monounsaturated fatty acids. Only two isolates contained two polyunsaturated fatty acids. Data obtained from the flow-lane incubator system would support a more economical and sustainable use of the benthic micro-organisms for biomass production. The produced lipids contained fatty acids suitable for a high-quality biodiesel production, showing high proportions of saturated and monounsaturated fatty acids. Data seem promising when taking into account the savings in cost and time derived from easy procedures for biomass harvesting, especially when being able to obtain the co-production of other valuable by-products.

Growing wastewater-born microalga Auxenochlorella protothecoides UMN280 on concentrated municipal wastewater for simultaneous nutrient removal and energy feedstock production

Using wastewater to grow algae is probably the most promising route to reduce production costs associated with nutrients and water. In this study, a newly isolated facultative heterotrophic freshwater microalgae strain, Auxenochlorella protothecoides UMN280, was examined for algal growth, wastewater nutrient removal efficiency, and lipid accumulation in batch and semi-continuous cultivation with various hydraulic retention time using concentrated municipal wastewater (CMW) as cultivation media. The results of the 6day batch cultivation showed that the maximal removal efficiencies for total nitrogen, total phosphorus, chemical oxygen demand (COD) and total organic carbon (TOC) were over 59%, 81%, 88% and 96%, respectively, with high growth rate (0.490d−1), high biomass productivity (269mgL−1d−1) and high lipid productivity (78mgL−1d−1). Further fatty acid methyl ester (FAME) analysis showed that the microalgal lipids were mainly composed of C16/C18 fatty acids (accounting for over 94% of total fatty acid), which are suitable for high-quality biodiesel production. The system could be scaled up from 100mL flasks to 25L BIOCOIL reactors, and semi-continuously operated at hydraulic retention time of 3days with a net biomass productivity of 1.51gL−1d−1 of dried algae.

Biodiesel production from a microalgal Chlorella sp. through the technology of in situ trasesterification

Biofuel production is now the focal point of world attention due to rapidly escalating demand for crude oil, major security concerns over supply and the environmental damage associated with crude oil extraction, processing and consumption. In the global energy crisis context, biodiesel attracts increasing attention worldwide and has core advantages over mineral diesel in that it is renewable, biodegradable, clean-burning, non-toxic and carbon neutral with respect to carbon dioxide related climate change. Recently, microalgae have long been identified as a potential feedstock due to their many advantages for biodiesel production. Microalgae produce cellular storage lipids in the form of triacetylglycerols (TAGs) which can be readily converted to fatty acid methyl esters (FAMEs) via a simple chemical transesterification reaction. The production of a fast growing, high lipid strain of algae that can be mass cultivated under controlled and engineered conditions will have overwhelming appeal as an feedstock for biodiesel production. We have successfully isolated local, indigenous strains of microalgae which could be preferable for microalgal lipid culture in biodiesel production. Our key objective is to maximize the cellular lipid content of selected strains of local microalgae which have a high biomass yield in engineered intensive bioreactors, on algal growth in photobioreactors PBRs - the natural choice as microalgae are phototrophic, utilizing light and CO2 for the production of energy and biomass via photosynthesis. The aims of this work are firstly to obtain high quality biodiesel production from a microalga Chlorella sp. through the technology of in situ transesterification. Secondly, the prediction properties of the obtanined Chlorella sp. biodiesel such as specific gravity at 150C, kinematic viscosity at 40oC, flash point, iodine value, cetane numeric value will be compared with biodiesel quality standard of Vietnam. The obtained results suggested that the in situ transesterification technology was a feasible and effective method for the production of high quality biodiesel from marine microalga.

High quality biodiesel production from pork lard by high solvent additive

Large scale biodiesel production by using low cost and abundant feedstock as waste animal fat is becoming more important due to petroleum reserves crisis and adverse environmental problems. This paper has experimentally developed a new method for lard synthesis by using suitable conditions of production with high solvent blending. A polynomial equation was obtained for lard biodiesel yields as a function of synthesis parameters. The validity of the predictive model was confirmed by validation experiments. The suitable combination for high quality biodiesel production from lard was less than 2.0 wt.% catalyst with 10:1 methanol/lard molar ratio and 65.0 wt.% solvent additive. The significant point of this method was to use high solvent blending ratios for lard synthesis to overcome poor solubility problem between highly concentrated free fatty acid pork lard and catalyst. Using this method, gave high yields of biodiesel in short reaction time. The evaluation of the synthesis was made using gas chromatography. The final products fulfilled all of the requirements of ASTM D6751-09 and EN 14214 standards. Overall, this process can be useful for larger scale industrial process with low energy consumption.

Subcritical co‐solvents extraction of lipid from wet microalgae pastes of Nannochloropsis sp.

In this paper subcritical co-solvents extraction (SCE) of algal lipid from wet pastes of Nannochloropsis sp. is examined. The influences of five operating parameters including the ratio between ethanol to hexane, the ratio of mixed solvents to algal biomass (dry weight), extraction temperature, pressure, and time were investigated. The determined optimum extraction conditions were 3:1 (hexane to ethanol ratio), 10:1 ratio (co-solvents to microalgae (dry weight) ratio), 90°C, 1.4 MPa, and 50 min, which could produce 88% recovery rate of the total lipids. In addition, electron micrographs of transmission electron microscopy (TEM) and scanning electron microscopy (SEM) were conducted to show that the algal cell presented shrunken, collapsed with some wrinkles and microholes after SCE extraction. The main composition of total lipids extracted under the optimum conditions was TAG which represented more than 80%. And the fatty acid profile of triglycerides revealed that C16:0 (35.67 ± 0.2%), C18:1 (26.84 ± 0.044%) and C16:1 (25.96 ± 0.011%) were dominant.Practical applications:The reported method could save energy consumption significantly through avoiding deep dewatering (for example drying). The composition of the extracted lipid is suitable for the production of high quality biodiesel.

Genetic variability in Cynara cardunculus L. domestic and wild types for grain oil production and fatty acids composition

Abstract This paper aimed to study the genetic variability within different types of Cynara cardunculus L., domestic and wild types, for their grain oil amount and oil fatty acid composition. The grain oils were extracted from 8 domestic cardoons and 4 wild cardoons, by Soxhlet method, and obtained oils were characterized for palmitic, stearic, oleic and linoleic acids by gas chromatography. The oil amount, resulted on average of accessions 216 g kg−1 DM with a good range of variability (CV = 11.7%). Unsaturated acids (oleic and linoleic) predominated over saturated ones (stearic and palmitic acids), the chemical characterization of extracted oil, showed the main compound (as % of analysed fatty acids), averaged for all populations, was linoleic acid (44.5%), followed by oleic acid (42.6%), palmitic acid (9.8%) and stearic acid (3.1%). In particular referring the oleic acid wild cardoon populations showed a mean value of 289 g kg−1 oil, against a mean value of 472 g kg−1 oil showed by domestic cardoon accessions. Three of the studied domestic cardoon (‘DC1’, ‘DC3’ and ‘DC7’) showed values higher than 795 g kg−1 oil, while all the other accessions had concentration lower than 370 g kg−1 oil. The three types of domestic cardoon ‘DC1’, ‘DC3’ and ‘DC7’ showed a fatty acids profile similar to genetic modified sunflower oil, representing new genetic material that potentially could be used for high quality biodiesel production, characterised by a low Iodine Number.

Production of microbial oil with high oleic acid content by Trichosporon capitatum

Microbial oils with high unsaturated fatty acids content, especially oleic acid content, are good feedstock for high quality biodiesel production. Trichosporon capitatum was found to accumulate lipid with around 80% oleic acid and 89% total unsaturated fatty acids content on nitrogen-limited medium. In order to improve its lipid yield, effects of medium components and culture conditions on cell growth and lipid accumulation were investigated. Optimization of media resulted in a 61% increase in the lipid yield of T. capitatum after cultivation at 28 °C and 160 rpm for 6 days. In addition, T. capitatum could grow well on cane molasses and afford a lipid yield comparable to that on synthetic nitrogen-limited medium. The biodiesel from the microbial oil produced by T. capitatum on cane molasses displayed a low cold filter plugging point (−15 °C), and so T. capitatum might be a promising strain to provide lipid suitable for high quality biodiesel production.

Production of Biodiesel with Acid Hydrolysate of Populus Euramevicana CV Leaves by Rhodotorula Glutinis

Populus euramevicana cv leaves acid hydrolysate has been utilized as a substrate for microbial oil production using Rhodotorula glutinis. Uniform design principles and single-factor experiments were employed to investigate the optimal culture conditions of the biodiesel production, which were pH 6.0, inoculum concentration 15%, yeast extract 7 g/L, peptone 3 g/L, hydrolytic saccharide concentration 40 g/L, KH2PO4 0.1%, 50 mL liquid volume in 150 mL shaking flask, and temperature 28°C. Under the optimized conditions, yeast accumulated lipids up to 28.55% on cellular biomass basis with lipid yield 4.62 g/L in 5L bioreactor without detoxification, and R. glutinis accumulated lipids up to 34.16% with lipid productivity reaching 6.18 g/L after detoxification. The analysis of composition of R. glutinis lipid revealed that R. glutinis could be an ideal host for high-quality biodiesel production. The properties of biodiesel produced by this process comply with the standards established by government institute.