Biodiesel Properties of Native Strain of Dunaliella Salina

ECORFAN Journal-Ecuador, 2020

Biodiesel is subject of research because it is less polluting when used in pure form or mixed with petroleum diesel. Microalgae are now a material new in research for mass production of biodiesel, so the techniques used for cell growth, biomass extraction and lipid extraction influence the profile of fatty acids susceptible to transesterification and consequently the quality of biofuel. This work shows the effect on the fatty acid profile of a Dunaliella tertiolecta strain using two lipid extraction techniques. For this, the culture was carried out in the medium F/2, the recovery of the biomass was carried out by sedimentation-flocculation with NaOH and once dry it was subjected to extraction with solvent by Soxhlet and by ultrasound to obtain lipids under the methodology by Bligh & Dyer. The fatty acids were analyzed by gas chromatography and the profile is made up of saturated-monounsaturated-polyunsaturated fatty acids and shows differences regarding the presence-absence and dry ...

Botswana International University of Science and Technology (BIUST), 2020

Production of biodiesel from microalgae has received worldwide recognition as an alternative to petroleum diesel. The process involves culturing, harvesting, drying, extraction, transesterification and characterisation of the microalgae biomass to biodiesel. The research aimed to investigate the potential of Dunaliella salina microalgae in Botash Company’s solar ponds for biodiesel production. Optimum salinity and nutrients concentrations that produced maximum biomass and lipids were investigated. Furthermore, the lipids and the biodiesel produced were identified, quantified and characterised. D. salina microalgae were isolated from the solar ponds and cultured in f/2 media under optimum conditions. One Factor at A Time (OFAT) design was used to determine the optimum salinity for the growth and lipid accumulation of the microalgae. A salinity concentration of 2.5 M produced the highest biomass concentration of 2480 mg L-1, biomass productivity of 58.40 mgL-1d-1, lipid content of 22.65 % and lipid productivity of 14.43 mgL-1d-1. In regard to nutrient optimisation, Plackett-Burman and Box-Behnken designs of response surface methodology (RSM) were used to optimise the culture media by selecting significant nutrients and their concentrations for culturing D. salina and promotion of lipids accumulation. In the first stage, Plackett-Burman method identified NaHCO3, NaH2PO4.2H2O and NaNO3 as factors that significantly influenced the biomass concentration, lipid content and lipid production. MgSO4.7H2O and micronutrients solution had a significance effect on the lipid content. The relationship on biomass concentration, lipid content and lipid production were predicted using a model that had an R2 value of 99.3% with a P-value of 0.000. In the second stage using Box-Behnken design, the nutrients selected in the first stage were further optimised and a predicted model was generated with an R2 value of 95.8%. The optimum medium that constituted 1302.4 mgL-1 NaHCO3, 22.5 mgL-1 NaH2PO4.2H2O, 181.1 mgL-1 NaNO3, 44.7 mgL-1 CaCl2, 2355.0 mgL-1 MgSO4.7H2O, 5.6 mlL-1 of micronutrients solution produced maximum lipid production of 181.1 mgL-1, which is 12.3% more than the 127.0 mgL-1 produced using the un-optimised medium. After approximately 36 days of culturing the cells were harvested and used to extract lipids by solvent extraction method, Thin Layer Chromatography (TLC) screened and approximated lipids to linoleic acid, oleic acid, and some triglycerides. Biodiesel was produced from the extracted lipids using alkali transesterification process. Fourier Transform Infrared (FTIR) identified chemical bonds in biodiesel with a strong peak at 1743 - 1742 cm-1 wavelength as triglycerides ester carbonyl functional group. Furthermore, the D. salina biodiesel’s chemical composition was quantified using Gas Chromatography (GC) and Mass Spectrometry (MS) spectrum that verified the presence of monounsaturated methyl esters. The physiochemical characterisation of D. salina biodiesel was in the recommended specification of the EN 14214, ASTM D6751 and SANS 1935:2004 standards indicating a good quality of the fuel. The D. salina biodiesel when compared to sunflower biodiesel and petroleum diesel had the highest ignition temperature, burnout temperature, ignition index and also the least comprehensive performance reflecting good thermal properties of the fuel. The thermal kinetics of D. salina biodiesel show a high pre-exponential factor (A) and Gibbs energy (∆G) but low activation energy (E) and entropy (∆S). The enthalpy (∆H) and higher heating value (HHV) were comparable to the ones for sunflower biodiesel and petroleum diesel. Based on the results of physio-chemical and thermal characterisation, the D. salina biodiesel could be used in boilers such as the ones in Botash Company for ignition and steam production purposes. In conclusion, the study was able to enhance lipids production during culturing stage, produce biodiesel through an effective selection of the best catalyst during the transesterification stage, identified and characterise the biodiesel.

Applied Energy, 2011

Due to increasing oil prices and climate change concerns, biodiesel has gained attention as an alternative energy source. Biodiesel derived from microalgae is a potentially renewable and carbon-neutral alternative to petroleum fuels. One of the most important decisions in obtaining oil from microalgae is the choice of algal species to use. Eight microalgae from a total of 33 isolated cultures were selected based on their morphology and ease of cultivation. Five cultures were isolated from river and identified as strains of Scenedesmus obliquus YSR01, Nitzschia cf. pusilla YSR02, Chlorella ellipsoidea YSR03, S. obliquus YSR04, and S. obliquus YSR05, and three were isolated from wastewater and identified as S. obliquus YSW06, Micractinium pusillum YSW07, and Ourococcus multisporus YSW08, based on LSU rDNA (D1-D2) and ITS sequence analyses. S. obliquus YSR01 reached a growth rate of 1.68 ± 0.28 day À1 at 680 nm and a biomass concentration of 1.57 ± 0.67 g dwt L À1 , with a high lipid content of 58 ± 1.5%. Under similar environmental conditions, M. pusillum reached a growth rate of 2.3 ± 0.55 day À1 and a biomass concentration of 2.28 ± 0.16 g dwt L À1 , with a relatively low lipid content of 24 ± 0.5% w/w. The fatty acid compositions of the studied species were mainly myristic, palmitic, palmitoleic, oleic, linoleic, g-linolenic, and linolenic acids. Our results suggest that S. obliquus YSR01 can be a possible candidate species for producing oils for biodiesel, based on its high lipid and oleic acid contents.

Latin American Journal of Aquatic Research, 2021

This research aims to evaluate the effect of molasses as a source of organic carbon on the growth and lipid profile of Dunaliella salina cultivated under different light regimes to determine its strategy and potential use to produce biodiesel. Two sources of nutrients (F/2 medium, F/2; molasses, M) and two light conditions (12 h light: 12 h darkness, 12L:12D) conformed four treatments (F/2 12L:12D, F/2 D, M 12L:12D, and MD) that were investigated with three replicates each. The concentration of microalgae produced by the groups under light conditions was more than double that of those grown in darkness. The highest biomass produced (46.91 ± 6.47 g L -1 ) was obtained in the F/2 medium with 12L:12D treatment, while the lowest (18.99 ± 0.78 g L -1 ) was in the M 12L:12D group. Regardless of the culture conditions, the lipids were mainly composed of the C16:0 and C18 fatty acids. The use of molasses as a culture medium produced the highest amount of C18:1, regardless of the light regim...

Microalgae is one of potential source for biodiesel due to high efficiency of solar energy conversion to chemical energy. Several microalgae also have high lipid content per dry weight of biomass. The aims of the present work to study the effects of temperature and nutrient depletion on the growth and lipid content of three selected microalgae (Dunaliella tertiolecta, Nannochloropsis sp and Scenedesmus sp) in view of their possible utilization as raw materials for biodiesel production. In addition, various lipid analysis methods were applied, such as gravimetric, Nile Red staining and FTIR spectroscopy. Algal growth and lipid content was strongly influenced by the variation of tested parameters; indeed, an increase or decrease temperature from ambient temperature and nutrient depletion practically increase in lipid content. Nile Red staining and FTIR spectroscopy are effective tool to analyze rapidly of lipid content from selected microalgae.

Bioprocess and Biosystems Engineering, 2018

Microalgae could be of importance for future biodiesel production as an alternative for a third generation of biofuels. To select the most appropriate strain for biodiesel production, three microalgae species, namely Isochrysis sp., Nannochloropsis maritima and Tetraselmis sp., isolated from Tunisian coast, were biochemically characterized. Initially, gas chromatography analysis showed that Isochrysis sp. and N. maritima contained 5-and 10-fold total fatty acids, respectively, more than Tetraselmis sp. Then, the two microalgae Isochrysis sp. and N. maritima were subject to random mutagenesis using ultraviolet-C radiation. Subsequently, a total of 18 mutants were obtained from both species. The neutral lipid evaluation on said 18 mutants allowed the retention of only 7 to further fatty acid characterization. Finally, gas chromatography revealed that the mutant 5c Isochrysis sp. was characterized by a high level of saturated fatty acids (52.3%), higher amount of monounsaturated fatty acids (29.3%), lower level of polyunsaturated fatty acids (18.4%) and a significant 1.3-fold increase in its C16-C18 content compared to the wild-type strain, which would make it an interesting candidate for biofuel production.

International Journal of Marine Science, 2013

Microalgae is one of potential source for biodiesel due to high efficiency of solar energy conversion to chemical energy. Several microalgae also have high lipid content per dry weight of biomass. The aims of the present work to study the effects of temperature and nutrient depletion on the growth and lipid content of three selected microalgae (Dunaliella tertiolecta, Nannochloropsis sp and Scenedesmus sp) in view of their possible utilization as raw materials for biodiesel production. In addition, various lipid analysis methods were applied, such as gravimetric, Nile Red staining and FTIR spectroscopy. Algal growth and lipid content was strongly influenced by the variation of tested parameters; indeed, an increase or decrease temperature from ambient temperature and nutrient depletion practically increase in lipid content. Nile Red staining and FTIR spectroscopy are effective tool to analyze rapidly of lipid content from selected microalgae.

Chemistry Central Journal, 2012

Microalgae have attracted major interest as a sustainable source for biodiesel production on commercial scale. This paper describes the screening of six microalgal species, Scenedesmus quadricauda, Scenedesmus acuminatus, Nannochloropsis sp., Anabaena sp., Chlorella sp. and Oscillatoria sp., isolated from fresh and marine water resources of southern Pakistan for biodiesel production and the GC-MS/MS analysis of their fatty acid methyl esters (FAMEs).

Biodiesel from oil crops, waste cooking oil and animal fat cannot realistically satisfy even a small fraction of the existing demand for transport fuels. As demonstrated here, microalgae appear to be the only source of renewable biodiesel that is capable of meeting the global demand for transport fuels. Marine microalgae Dunaliella salina and Nannochloropsis sp. was cultured in indoor and outdoor systems and harvested biomass was utilized for biodiesel fuel production. The direct transesterification of microalgae biomass shows good biodiesel yield where Dunaliella salina yielded 66.6 % and Nannochloropsis sp. 68.5% respectively. It is inferred that the fatty acid methyl esters (FAME) such as palmitic acid (16:0), oleic acid (18:1) and linolenic acid (18:3) which found in microalgae are accountable for yielding more biodiesel than other oil crops. It is understood that, the marine microalgae Nannochloropsis sp and Dunaliella salina were considered as promising feedstock for biodiesel production.

Energies

Microalgae are considered to be potentially attractive feedstocks for biodiesel production, mainly due to their fast growth rate and high oil content accumulated in their cells. In this study, the suitability for biofuel production was tested for Chlorella vulgaris, Chlorella fusca, Oocystis submarina, and Monoraphidium strain. The effect of nutrient limitation on microalgae biomass growth, lipid accumulation, ash content, fatty acid profile, and selected physico-chemical parameters of algal biodiesel were analysed. The study was carried out in vertical tubular photobioreactors of 100 L capacity. The highest biomass content at 100% medium dose was found for Monoraphidium 525 ± 29 mg·L−1. A 50% reduction of nutrients in the culture medium decreased the biomass content by 23% for O. submarina, 19% for Monoraphidium, 13% for C. vulgaris and 9% for C. fusca strain. Nutrient limitation increased lipid production and reduced ash content in microalgal cells. The highest values were observe...