Potential of microalgae scenedesmus obliquus grown in brewery wastewater for biodiesel production (original) (raw)
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Fuel, 2020
Due to expensive culture realizations and low lipid yields, microalgae-based biodiesel production still lacks economic viability at an industrial-scale. Optimization of lipids and fatty acid methyl esters (FAMEs) distribution is a necessary condition to get sustainable microalgae biodiesel production. Nutritional sources (nitrogen, phosphorous, carbon and iron) influence the lipid accumulation and biomass production yield. The aim of this study is to get high-quality biodiesel by a microalgae-yeast co-culture based on the selection of culture media micronutrients' distribution. A response surface-based combination of NaNO 3 , K 2 HPO 4 and FeSO 4 *7H 2 O nutrients increases biomass and lipids accumulations. The obtained highest biomass and lipids contents are 1.68 gL −1 and 27.77%, respectively. Under the selected optimized micronutrients' composition, high-saturated fatty acids are obtained if high ratio of N/P (6:1 and 11:1) and unsaturated fatty acid under N/P ratio of (9:1) are considered. These results suggest microalgae-yeast co-culturing under controlled N/P ratio in the culture medium produce desirable lipids distributions, yielding better biodiesel quality and equilibrium between biomass and lipids accumulation. The selected micronutrient combination (with the selected N/P ratio) leads to augment the lipids content which is transformed into biodiesel. Biodiesel quality (determined by cetane number, iodine value, cloud point, oxidation stability, viscosity), is evaluated considering microalgae lipids and FAMEs produced by transesterification process. Fourier transform infrared (FTIR) corroborates the lipids distribution, which can be used to produce high quality biodiesel. Gas chromatography (GC) verifies the production of desirable methyl esters (C16 and C18).
World Journal of Microbiology and Biotechnology, 2013
Nowadays, microalgae are discussed as a promising feedstock for biodiesel production. The present study examines the possibility of enhancement of fatty acid productivity of Scenedesmus obliquus by modifications of the culture medium composition. The effect of different concentrations of sodium bicarbonate, salinity, potassium nitrate, glycerol and sugarcane molasses on the enhancement of biomass and esterified fatty acids production was studied. NaHCO 3 caused an increase in the biomass productivity at low concentrations (0.5 g L -1 ), while negatively affected fatty acid productivity at all tested concentrations. Increase of salinity enhanced both biomass and fatty acid productivity. The optimum NaCl concentration and sea water ratio were 0.94 g L -1 and 25 % which resulted in 56 and 39 % increase in fatty acid productivity, respectively. Nitrogen deficiency showed increase in fatty acid content by 54 % over control but fatty acid productivity was decreased as a result of growth inhibition. Nitrogen-free cultures and cultures treated with -50 % concentrations of KNO 3 showed 96 and 42 % decrease in EFA productivity, respectively, as compared with the control. Addition of 0.05 and 0.1 M of glycerol increased the biomass productivity by 6 and 5 %, respectively but showed no significant effect on fatty acid productivity as a result of decrease in fatty acid content. Finally, usage of sugarcane molasses stimulated both biomass and fatty acid content. The increase in fatty acid productivity was 32, 65 and 73 % above the control level at 1, 3 and 5 g L -1 of sugarcane molasses, respectively.
Journal of Ecological Engineering
Local single cell microalgae isolated from a wastewater swamp and identified as Scenedesmus obliquus was used to determine its applicability for utilization of domestic wastewater for biomass and lipid production. Secondary treated domestic wastewater with or without mixing of growth medium was used to cultivate S. obliquus for the biomass and lipid production as a renewable feedstock for biodiesel. S. obliquus showed the highest OD when grown in 100% Bold's basal medium (BBM). S. obliquus utilized 95.2% and 78.5% of P and N contents, respectively, when grown in 25% WW+75% BBM mixture and the utilization efficiency of both elements decreased with the increasing wastewater portion in the mixture. Although the BBM displayed the highest dry biomass and lipid production (25.15% of the cell dry biomass). The lowest values were recorded for the uninoculated wastewater, followed by 100% wastewater enriched with S. obliquus. The obtained data revealed that the lipid classes of S. obliquus differs according to the cultivation medium and conditions. The highest percentage of C16-C18 fatty acids (54.76% from total lipids) were recorded in case of algae cultivated in 100% wastewater, followed by 46.96% in case of 100% BBM medium. These results suggest the utilization of mixtures containing a higher portion of secondary treated wastewater, such as 75% WW+25% BBM or 50% WW+50% BBM, could increase the economical production of the lipid-rich microalgae S. obliquus for biodiesel through saving water and nutrients.
Microalgae are discussed as an alternative source for the production of biofuels. The lipid content compared to cultivation time of used species is the main reason for any choice of a special strain. This paper reviews more analytical data of 38 screened microalgae strains. After the cultivation period, total content of lipids was analysed. The extracted fatty acids were quantified as fatty acid methyl esters by GC analysis. The amino acids were analysed by HPLC. Chlorella sp., Chlorella saccharophila, Chlorella minutissima and Chlorella vulgaris were identified as species with the highest productivity of fatty acids relevant to transesterification reactions. The components were mainly linoleic acid, palmitic acid and oleic acid. To increase productivity of highly saturated fatty acids, cultivation parameters light intensity and temperature were varied. In this manner, the ideal conditions for biodiesel production were defined in this publication.
BioEnergy Research, 2012
The viability of algae-based biodiesel industry depends on the selection of adequate strains in regard to profitable yields and oil quality. This work aimed to bioprospecting and screening 12 microalgae strains by applying, as selective criteria, the volumetric lipid productivity and the fatty acid profiles, used for estimating the biodiesel fuel properties. Volumetric lipid productivity varied among strains from 22.61 to 204.91 mg l −1 day −1 . The highest lipid yields were observed for Chlorella (204.91 mg l −1 day 1 ) and Botryococcus strains (112.43 and 98.00 mg l −1 day −1 for Botryococcus braunii and Botryococcus terribilis, respectively). Cluster and principal components analysis analysis applied to fatty acid methyl esters (FAME) profiles discriminated three different microalgae groups according to their potential for biodiesel production. Kirchneriella lunaris, Ankistrodesmus fusiformis, Chlamydocapsa bacillus, and Ankistrodesmus falcatus showed the highest levels of polyunsaturated FAME, which incurs in the production of biodiesels with the lowest (42.47-50.52) cetane number (CN), the highest (101.33-136.97) iodine values (IV), and the lowest oxidation stability. The higher levels of saturated FAME in the oils of Chlamydomonas sp. and Scenedesmus obliquus indicated them as source of biodiesel with higher oxidation stability, higher ). The third group, except for the Trebouxyophyceae strains that appeared in isolation, are composed by microalgae that generate biodiesel of intermediate values for CN, IV, and oxidation stability, related to their levels of saturated and monosaturated lipids. Thus, in this research, FAME profiling suggested that the best approach for generating a microalgae-biodiesel of top quality is by mixing the oils of distinct cell cultures.
Bioresource Technology , 2016
h i g h l i g h t s Phosphate, pH and light intensities have marked effect on the FA profile of alga. 60 mg/L phosphate has favoured high biomass and lipid concentration. Illumination of 6000 lux was suitable for biomass and lipid production. Biomass increased at pH 8, whereas pH 6 favoured lipid content. Favourable phosphate, pH and light conditions resulted in good fuel properties. a b s t r a c t The present study dealt with biomass, lipid concentration, fatty acid profile and biodiesel properties of microalga Scenedesmus abundans under different phosphate concentrations, pH and light intensities, one at a time. Among different phosphate concentrations, higher biomass (770.10 ± 11.0 mg/L) and lipid concentration (176.87 ± 4.6 mg/L) were at the concentration of 60 mg/L. Light intensity at 6000 lux yielded higher biomass and lipid concentration of 742.0 ± 9.7 and 243.15 ± 9.1 mg/L, respectively. The biomass (769.0 ± 12.3 mg/L) and lipid (179.47 ± 5.5 mg/L) concentration were highest at pH 8 and pH 6, respectively. All the culture treatments showed marked effect on the fatty acid profile and biodiesel properties of the extracted oil. FAME derived biodiesel properties were compared with European biodiesel standards (EN 14214), Indian biodiesel standards (IS 15607) and American biodiesel standards (ASTM D 6751-08) to assess the suitability of algal oil as biodiesel feedstock.
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...
The viability of algae-based biodiesel industry depends on the selection of adequate strains in regard to profitable yields and oil quality. This work aimed to bioprospecting and screening 12 microalgae strains by applying, as selective criteria, the volumetric lipid productivity and the fatty acid profiles, used for estimating the biodiesel fuel properties. Volumetric lipid productivity varied among strains from 22.61 to 204.91 mg l −1 day −1 . The highest lipid yields were observed for Chlorella (204.91 mg l −1 day 1 ) and Botryococcus strains (112.43 and 98.00 mg l −1 day −1 for Botryococcus braunii and Botryococcus terribilis, respectively). Cluster and principal components analysis analysis applied to fatty acid methyl esters (FAME) profiles discriminated three different microalgae groups according to their potential for biodiesel production. Kirchneriella lunaris, Ankistrodesmus fusiformis, Chlamydocapsa bacillus, and Ankistrodesmus falcatus showed the highest levels of polyunsaturated FAME, which incurs in the production of biodiesels with the lowest (42.47-50.52) cetane number (CN), the highest (101.33-136.97) iodine values (IV), and the lowest oxidation stability. The higher levels of saturated FAME in the oils of Chlamydomonas sp. and Scenedesmus obliquus indicated them as source of biodiesel with higher oxidation stability, higher ). The third group, except for the Trebouxyophyceae strains that appeared in isolation, are composed by microalgae that generate biodiesel of intermediate values for CN, IV, and oxidation stability, related to their levels of saturated and monosaturated lipids. Thus, in this research, FAME profiling suggested that the best approach for generating a microalgae-biodiesel of top quality is by mixing the oils of distinct cell cultures.
The feasibility of biodiesel production by microalgae using industrial wastewater
Bioresource Technology, 2012
This study investigated nitrogen and phosphorus assimilation and lipid production of microalgae in industrial wastewater. Two native strains of freshwater microalgae were evaluated their biomass growth and lipid production in modified BBM medium. Chlamydomonas sp. TAI-2 had better biomass growth and higher lipid production than Desmodesmus sp.TAI-1. The optimal growth and lipid accumulation of Chlamydomonas sp. TAI-2 were tested under different nitrogen sources, nitrogen and CO 2 concentrations and illumination period in modified BBM medium. The optimal CO 2 aeration was 5% for Chlamydomonas sp. TAI-2 to achieve maximal lipid accumulation under continuous illumination. Using industrial wastewater as the medium, Chlamydomonas sp. TAI-2 could remove 100% NH 4 + -N (38.4 mg/L) and NO 3 À -N (3.1 mg/L) and 33% PO 4 3À -P (44.7 mg/L) and accumulate the lipid up to 18.4%. Over 90% of total fatty acids were 14:0, 16:0, 16:1, 18:1, and 18:3 fatty acids, which could be utilized for biodiesel production.
Characterization of biodiesel produced from microalgae grown on fish farm wastewater
SN Applied Sciences
This project investigated the influence of fish wastewater nutrients on properties of fatty acid methyl esters (FAME) of three microalgae species (Tetradesmus obliquus, Heterochlorella luteoviridis and Chlamydomonas reinhardtii) cultivated in unmodified and modified fish farm wastewater (FFW). The fuel properties obtained from the FAME of microalgae cultivated in FFW were then compared to the fuel properties obtained from FAME of the same microalgae species cultivated in a standard growth media of modified tris-acetate-phosphate. FFW nutrients supported the accumulation of desirable biodiesel fatty acids. C16-C18 were the main fatty acid component in all samples making up to 95%. All samples had saturated fatty acids above 22% and over 60% unsaturated fatty acids. Fuel properties of biodiesel produced from microalgae species cultivated in FFW were similar to fuel properties of biodiesel from the same species cultivated in the standard growth media. When compared to ASTM D6751-02 and EN 14214 biodiesel standards, biodiesel from FFW had desirable fuel properties (cetane number, kinematic viscosity, density, higher heating value, cold filter plugging point and iodine value). Overall, Chlamydomonas reinhardtii (in both FFW media) had the most suitable biodiesel property, especially when looking at the cold filter plugging point.