Microwave treatment of wet algal paste for enhanced solvent extraction of lipids for biodiesel production (original) (raw)
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Microalgal Lipid Extraction and Evaluation of Single-Step Biodiesel Production
This work examined solvent extraction of lipid from microalgae for production of renewable biofuels, thereby allowing appropriate selection of solvent and extraction methods. The results of this study revealed that the mixture of chloroform and methanol (C/M) at the ratio of 2:1 (v/v) could extract the highest amount of total lipid from algae, while hexane was found to be a good solvent, concerning the selectivity for targeted lipids such as mono-, di-and tri-glycerides. As far as the extraction methods are concerned, applying disruption, especially with microwave could accelerate the rate of lipid extraction from algae with tough cell walls such as Chlorella vulgaris. On the other hand, ultrasound and microwave assisted extraction techniques added no benefits to the extraction of lipid from powder of Haematococcus pluvialis whose cell wall was previously damaged. Other than lipid extraction, this paper concerns with the development of transesterification process for algal lipid using C. vulgaris as a model system. Here, the effects of the amount of catalyst, alcohol to biomass ratio and reaction time on biodiesel yield were investigated. We also studied a single-step biodiesel production where extraction and transesterification simultaneously took place and comparison between this method and the conventional two-step biodiesel production process was made.
Effects of ultrasonic and microwave pretreatments on lipid extraction of microalgae
Bioprocess and Biosystems Engineering, 2014
The extraction of lipids from microalgae cells of Botryococcus braunii and Chlorella vulgaris after ultrasonic and microwave pretreatment was evaluated. Cell disruption increased the lipid extraction efficiency, and microwave pretreatment was more effective compared with ultrasonic pretreatment. The maximum lipid yield from B. braunii was 56.42% using microwave radiation and 39.61% for ultrasonication, while from C. vulgaris, it was respectively 41.31% and 35.28%. The fatty acid composition in the lipid extracts was also analyzed. The methane yield from the residual extracted biomass pretreated by microwaves ranged from 148 to 185 NmL CH 4 /g VS for C. vulgaris and from 128 to 142 NmL CH 4 /g VS for B. braunii. In the case of ultrasonic pretreatment, the methane production was between 168 and 208 NmL CH 4 /g VS for C. vulgaris, while for B. braunii ranging from 150 to 174 NmL CH 4 /g VS. Anaerobic digestion showed that lipid-extracted biomass presented lower methane yield than non-lipid-extracted feedstock, and higher amount of lipid obtained in the extraction contributed less methane production. Anyway, anaerobic digestion of the residual extracted biomass can be a suitable method to increase economic viability of energy recovery from microalgae.
Solvent Extraction Techniques of Lipid from Algal species in Wastewater Treatment Station
Egyptian Journal of Chemistry
B IODIESEL production process relies on various key steps one of which is the lipid extraction from microalgae cells using economic techniques. In this study, Algal community structure and physicochemical parameters of the wastewater treatment plant (Beni-Suef, Egypt), are determined from March 2016 to February 2017. In this study, we focused on the lipid extracted from wild mixed culture of Chlorella sp. which is the dominant from December 2016 to February 2017. Lipid content and fatty acid profiling of Chlorella sp. are investigated using three different methods (1) conventional extraction (CE), (2) ultrasonic assisted extraction (UAE) and (3) microwave assisted solvothermalextraction (MASE). MASE showed the highest lipid yield of 37.9±0.13%. SEM micrographs showed that MASE had the most distributive effect for algae cells compared to UAE and CE. Six different solvents are tested for MASE technique namely hexane: isopropanol (3:2), hexane: ethanol (1:1), chloroform: methanol (1:1), diethyl ether, ethanol and methanol. A strong linear relation between the direct electric constant and yield percent is obtained with methanol showing the highest yield. The GC-analysis of extracted lipids shows that methanol resulted in the highest percentage of palmitic acid (45.5%). The chemical composition of extracted lipids shows promise towards further conversion to biodiesel.
Microwave and ultrasound enhanced extractive-transesterification of algal lipids
Microwave/ultrasound based extractive-transesterification of algal lipids was studied. Microwave and ultrasound show higher yields/conversions than Bligh and Dyer (BD) Method. Lipid yields were (MW-18.8%; US-18.5%) and FAEE conversions were (MW-96.2%; US-95.0%). Specific energy consumption for MW was 26 MJ/kg and US was 44 MJ/kg biodiesel. The MW or US methods may result in chemical, energy, and economic savings.
Microwave Heating Impact on the Oil Yield from Botryococcus braunii Algae Biomass
Environment, Green Technology, and Engineering International Conference, 2018
Stage, which is still difficult for researchers is extraction of the lipids, especially the cell disruption stage prior to the extraction process. Strength of cell walls of microalgae makes lipids difficult to access. The aim of the experiment was to determine the influence of microwave electromagnetic radiation on the efficiency of lipid extraction from Botryococcus braunii microalgae by Bligh & Dyer method. he use of microwave heating to disintegrate the biomass of microalgae allowed to increase the yield of lipids from 18% in Stage I to 38% in Stage II in incubation time of 15 min in 45 °C.
2015
Background: This study aimed at determining the appropriate method for dewatering and drying biomass and selecting a suitable organic solvent for lipid extraction. Methods: Nannochloropsis Oculata was cultured in Gillard F/2 medium and after reaching the end of the stationary growth phase, algal biomass was separated from aqueous by centrifuge and dried through three methods: Oven, Air-dried and Lyophilized. Soxhlet apparatus achieved lipid extraction of all samples: diethyl ether, n-hexane and n-pentane using three solvents. At each stage, the quantity and quality of the extracted lipids were determined by Gas Chromatography. Results: In all three drying methods, palmitic acid and palmitoleic acid, and most significantly fatty acid composition of microalgae were extracted. The fatty acid composition of palmitic acid extracted by Diethyl ether was significantly more than the other two solvents. Maximum production of triglyceride was observed in Lyophilized and air-dried microalgae w...
Biodiesel Production from Microalgae with Trans-esterification Method Using Microwave
IOP Conference Series: Materials Science and Engineering, 2019
Microalgae has a highly potential to be biodiesel fuel due to its high lipid content. The research used Nannochloropsis oculata microalgae refer to high lipid content (approximately 68%). The objectives of this research are to study edible oil extraction process from Nannochloropsis oculata, to study the effect of microwave on biodiesel yield using KOH catalyst, time reaction as well as catalyst percentage. The trans-esterification process was carried out on microwave with lipid molar-methanol comparison of 1:10, microwave power, reaction time and catalyst composition were also varied. It was found that the addition of co-solvent (addition n-hexane) seems to give the best result in terms of yield, i.e. 54.19%, which was obtained at a 600-watt microwave power, reaction time of 40 min, and 2.5% catalyst concentration. The fatty acid consists of several major constituents, such as palmitic acid 84.81%, oleic acid 12.41% stearic acid 1.87% and linoleat 0.88%. It can be concluded from th...