Transesterification Of Microalgae Research Articles

Transesterification of Microalgae from Food Waste via Acid Catalyst for Biodiesel Production

Recently, numerous studies have presented the potential of various feedstock of biodiesel catalysed with acid catalysts and its performance. This study examines the potential of microalgae from food waste for biodiesel production by a homogeneous acid catalyst in a transesterification reaction. Initially, lipid was extracted from the microalgae using the microwave-assisted extraction (MAE) method. Then, the lipid was transesterified using a sulphuric acid catalyst under different conditions to decide the optimum condition. About 50% of the lipid was extracted from the microalgae when 400 W of microwave power was used for 15 minutes. The biodiesel yield of 76% has been attained from transesterifying the extracted lipid with methanol using 9:1 of methanol to oil molar ratio, 2.5 wt% of catalyst dosage for 3 hours at 65°C. Overall, this study has shown the potential of microalgae from food waste as one of the options for biodiesel’s feedstock catalysed by acid.
 Keywords: Biodiesel, food waste, microalgae, transesterification, acid catalyst, microwave assisted extraction (MAE)

Potential of microalgae for phytoremediation of various wastewaters for nutrient removal and biodiesel production through nanocatalytic transesterification

AbstractTetraselmis indica, a strain of microalgae, was cultivated in four distinct wastewaters in a photobioreactor of 1000 ml in a 16:8 light/dark period beneath the light intensity of 94.5 μmol m−2 s−1 for 14 days. The maximum biomass growth of 1125 mg/L was attained in the sewage wastewater (SWW). The T. indica eliminated the maximum pollution load from the primary wastewater of the paper mill (PWW), which was 94.95% nitrate, 96.625% phosphate, 99.5% ammonia, 72.8% COD, 94.14% BOD, and 98.9% TDS and heavy metals (94.84% Pb, 93.83% Mg, 99.78% Cu, 81.25% Mn, 94% Cd, 70.34% Zn, 99.84% Fe). The effectiveness of a lithium‐impregnated calcium oxide 1.75‐Li‐CaO nanocatalyst in the transesterification of microalgae was evaluated after growing an appropriate amount of microalgae on all four wastewaters. The nanocatalyst 1.75‐Li‐CaO was prepared by the wet impregnation method and characterized by various structural and spectral techniques. The scanning electron microscopy study shows the structure of nanocatalyst, which is in the shape of oval and hexagonal with a particle size of 20 nm. The Fourier transform infrared spectroscopy spectrum confirms that the nanocatalyst contains necessary functional groups, which were visible at 1470 cm−1. Because of its highest basic strength, 1.75‐Li‐CaO exhibits the highest activity for trans‐esterifying microalgal oil. The FAME profile of PWW‐based microalgae through nanocatalytic transesterification shows the existence of myristic acid (2.81%), stearic acid (5.28%), palmitic acid (38.74%), oleic acid (16.43%), linoleic acid (21.19%), and arachidic acid (5.85%). Thus, this research work validates that microalgae grown on SWW have the highest biomass output, and microalgae cultivated on PWW have the highest FAME yield when used to make biodiesel using nanocatalytic transesterification.

Simultaneous Extraction and In-Situ Transesterification of Chlorella vulgaris Using Microwave-Assisted Method for Biodiesel Production

This research aims to study the simultaneous extraction and transesterification of Chlorella vulgaris (C. vulgaris) using microwave irradiation with methanol as solvent and potassium hydroxide (KOH) as catalyst. The microwave-assisted insitu transesterification of C. vulgaris is assessed at various ratios of biomass-to-methanol, reaction times, and catalyst concentrations during the centrifugation and evaporation process. Gas chromatography-mass spectrometry (GC-MS) analysis is performed to confirm fatty acid methyl ester (FAME) composition. Biodiesel preparation is carried out by simultaneous extraction and transesterification of microalgae from C. vulgaris. The product is then characterized using Fourier transform infrared spectroscopy (FTIR) and proton nuclear magnetic resonance (1H-NMR); microalgae are observed using scanning electron microscopy (SEM). The highest amount of FAME is obtained at a biomass-to-methanol ratio of 1:12, reaction time of 40 min, and catalyst concentration of 2 wt%. Biodiesel shows conversion to about 77.64% of methyl ester (methyl myristate, methyl palmitoleate, methyl linoleate, methyl oleate, methyl arachidonate, and methyl 5,8,11,14,17-eicosapentanoate).

Microalgal biomass as a biorefinery platform for biobutanol and biodiesel production

Microalgal biorefineries have recently emerged as a potentially economically viable option for the co-production of value-added products and fuels, such as biodiesel (via the transesterification of lipids) and biobutanol (via the fermentation of carbohydrates). Whilst microalgal biodiesel has been studied extensively, microalgal biobutanol has received less attention due to the low product yields of the biochemical process from which biobutanol is obtained: the Acetone-Butanol-Ethanol (ABE) fermentation. In this work, we evaluate the potential of a microalgae-based biorefinery by: i) quantifying biobutanol production via ABE fermentation of microalgae (raw and hydrolysate form) using a medium optimised via surface response analysis (SRA) methodology; ii) quantifying biodiesel (fatty acid methyl esthers, FAMEs) production via transesterification of microalgae (raw, hydrolysed, and fermented form). Using SRA-optimised medium, butanol fermentation yields of 10.31% (g g−1 cdw) and 10.07% (g g−1 glucose) were attained by microalgae in raw and hydrolysate form, respectively. Meanwhile, the raw, hydrolysed, and fermented microalgae yielded up to 0.92%, 3.82% and 3.29% (g g−1 cdw) biodiesel, respectively. Results highlight the importance of pre-treatment methods and further support the development of microalgal biorefineries for dual biofuel production.

Evaluation of in-situ transient simultaneous cell disruption and transesterification of microalgae

Microalgae has recently been highlighted as source of valuable products including biofuel. The production process of biofuels from microalgae involves mass cultivation, harvesting, deep dewatering, lipid extraction and biofuel conversion. In this work, lipids from microalgae Navicula sp. were obtained using multifunctional process that consists of acid hydrolysis or cellular disruption, oil extraction and in situ transesterification. The effect of alcohol added to produce ethyl and methyl esters on lipid extraction efficiency was evaluated using methanol and ethanol in order to determine the most suitable route for obtaining the high values of lipids and total reducing sugar. The highest lipid extraction efficiency and total reducing sugar (7.72 % and 2.63 mg/ml, respectively) was obtained for methanol. The low lipid extraction efficiency of multifuctional process is due to transesterification of lipids that gradually released into the system. The formation of alkyl esters was confirmed by FTIR with an increase in carbonyl peak as the reaction progressed, thus muntifuctional process reduce cost of alkyl esters production by eliminating the step of lipid extraction by solvent.

Transesterification of marine macroalgae using microwave technology

ABSTRACTBiodiesel is renewable and environmental friendly, with calorific value equivalent to regular fossil fuel. This fuel can be produced from a variety of feedstocks, such as first-generation biodiesel feedstock (corn, peanut, soybean), second generation (jatropha, animal fats, waste cooking oils, macroalgae), and third generation (microalgae). Among these feedstocks, biodiesel production from microalgae has drawn special attention for different reasons: they have high lipid content and high growth rates; they are tolerant to severe environmental conditions; they offer the possibility of sequester carbon dioxide from the flue gases; their harvesting and transportation are economical compared to other crops; and they have very high photosynthetic yields compared to other terrestrial plants. The advantage of using macroalgae recollected on the beaches as raw material is that allows to obtained energy from a residue.Microwave-assisted extraction and transesterification of microalgae is being researched as a solution for biodiesel production by its benefits, such as shorter reaction times and less amount of heat energy to obtain biodiesel. It is due to the fact that microwaves can easily penetrate through the cell wall structure to extract and transesterify the oils into biodiesel.The aim of this research was to explore the possibility of carrying out the microwave-assisted transesterification of three marine macroalgae (brown and green). Different experimental runs were carried out with different process parameters such as macroalgae-to-methanol ratio, reaction time and catalyst concentrations. Based on the obtained results, the best conditions for microwave-assisted transesterification reaction were macroalgae-to-methanol ratio of 1:15 (wt/vol), sodium hydroxide concentration of 2 wt% and reaction time of 3 min.

Application of Factorial Design Methodology for Optimization of Transesterification Reaction of Microalgae Lipids

This study investigates the effects of alkali catalyst quantity, reaction temperature, reaction time, and acid catalyst quantity on biodiesel production via the transesterification of microalgae using two-level four-factor full factorial design. Under the experimental range considered, the most important factor for FAME yield is the base catalyst quantity. The FAME yield increases with increasing base catalyst quantity. The reaction time and acid catalyst quantity also have positive influences. There is an appreciable interaction between alkali catalyst quantity and the acid catalyst quantity, and thus the effects of these variables must be considered jointly. The best results for laboratory-scale biodiesel production via transesterification were obtained at a 1:65 weight ratio of dry microalgal biomass to alkali catalytic methanol (NaOH/MeOH, 2.5wt.%), with the acid catalysis process (HCl/MeOH, 5.8 vol.%), a 60oC reaction temperature, and a 30-min reaction time.

Biodiesel Production through Direct Transesterification of Microalgae with Alcohol via Ultrasonic Wave

A one-step extraction/transesterification process was developed to directly convert microalgae into biodiesel in the presence of catalyst, KOH using ultrasonic irradiation. The influences of various parameters on the transesterification reaction, including the reaction time, temperature, catalyst concentration, methanol to microalgae mass ratio and ultrasonic power, were investigated. And the optimum conditions for the transesterification process have been obtained as mass ratio of methanol to microalgae as 4:1, catalyst concentration of 7wt.%, temperature as 70oC and ultrasonic power as 100W with an irradiation time of 30 min by orthogonal experiments L9(34 )．Under these conditions, the conversion of fatty acid methyl esters was up to 4.0%.