In situ biodiesel production from wet Chlorella vulgaris under subcritical condition

Process application of Subcritical Water Extraction (SWE) for algal bio-products and biofuels production

“…With increasing residence time, the aqueous phase and solid residue showed a gradual decrease while the gaseous yield gradually increased. Tsigie et al [31] showed that the fatty acid methyl ester (FAME) yield increased with increasing reaction time during SWE for biodiesel production from C. vulgaris. It has also been suggested that a longer residence time is essential to increase FAME yield, and the series of process steps takes place in the order: cell wall breakage, release of lipids out of the cell, and reaction of lipids with methanol [31].…”

“…Tsigie et al [31] showed that the fatty acid methyl ester (FAME) yield increased with increasing reaction time during SWE for biodiesel production from C. vulgaris. It has also been suggested that a longer residence time is essential to increase FAME yield, and the series of process steps takes place in the order: cell wall breakage, release of lipids out of the cell, and reaction of lipids with methanol [31]. Longer retention times are recommended for repolymerization of small organic materials formed from protein hydrolysis [49].…”

“…Biocrude, a precursor of biodiesel, is the main product generally targeted from SWE of algal biomass. After refining, the biocrude is used directly or co-processed with petroleum diesel as a transportation fuel [30,31]. Biocrude can also be used as the feedstock to produce other bio-products such as resins and polyurethane foam materials [30].…”

In situ transesterification of Jatropha curcas L. seeds in subcritical solvent system

“…This has the potential of greatly lowering biodiesel production cost. In order to eliminate the step of oil extraction from seeds or microbial cells, in situ transesterification of oil seeds or microbial biomass under suband super-critical methanol conditions has been extensively studied [10][11][12][13][14][15][16]. Due to the high oil content of Jatropha curcas L. (JCL) seeds, the high yield of oil seeds and its easy of cultivation, non-edible oil from JCL seeds has recently been suggested as the next generation feedstock oil for biodiesel production.…”

Biodiesel production under subcritical solvent condition using subcritical water treated whole Jatropha curcas seed kernels and possible use of hydrolysates to grow Yarrowia lipolytica

“…In-situ transesterification of wet activated sludge under subcritical conditions (448 K, 8 h) was studied by Huynh et al [14], with a fatty acid methyl ester (FAME) yield comparable to that of the conventional acid catalyzed reaction which required 24 h. The same process was applied utilizing wet oleaginous yeast (Yarrowia lipolytica) cells [15] and wet microalgae (Chlorella vulgaris) cells [16]. Levin et al [17] utilized wet microalgal biomass to carry out carbonization at 523 K. Through carbonization, algal biomass was easily separated from water (culture media) thus resulting in lower moisture for subsequent transesterification step.…”