quickly, also without any preparation application on in-situ humid biomass is
possible. For instance, grinding or simple pressing with algal paste or a diluted
algal suspension with water content higher than 60% cannot be used proficiently. In
contrast to other processes ultrasonic can be applied to wet biomass more effectively.
The process of cell destruction is accompanied by extraction of the lipids. Most
extensively used solvents include chloroform along with methanol. Other extraction
solvents include acetone, ethanol, acetone, and iso-propyl alcohol showing various
choices of efficiencies in extraction of lipid.
1.4.2 High-Pressure Homogenization
Charles Stacy French invented high-pressure homogenization. In this process of cell
disruption, the feed is passed through a very tiny orifice under high pressure which
results in hydraulic force creation and results in cell disruption. HPH was widely
used in extraction and sterilization of the inner constituents of micro-organisms.
Numerous benefits include formation of little heat, risk of thermal degradation is also
lower, lower reactor cooling rate, dead volume is almost nil, and simple scale up.
1.5 Extraction of Lipid
It is a critical step to the use of algae to produce fuels. It is probably an affordable
choice too. For release of the preferred products the algae cells must be subjected to
cell disruption. Methods include: 1) mechanical methods such as bead beating, 2)
electric field application, 3) application of sonic waves, 4) shock through osmosis,
and 5) expelling through manual press. Biological and chemical methods include: 1)
solvent extraction (single solvent, co-solvent, and direct reaction by transesterification), 2) supercritical fluids, and 3) enzymatic extraction.
1.5.1 Single Solvent Extraction
Among the commonest extraction techniques is the single extraction of solvents. A
lipid-like solvent, for instance, hexane, petroleum ether, or other solvent (which is
merely a light solvent and petroleum based in nature) is used. This method is
commercial. Extraction proceeds at high temperatures and with high pressure. The
benefits include an increased rate of mass transmission and solvent availability, and a
decreased immiscible solvent dielectric constant. A co-solvent method is a little
different to use. A solvent is chosen on two parameters. Option should include: 1) a
co-solvent polar in nature that disturbs the algal membrane cells, and 2) a co-solvent
with lesser polarity to better suit the extracted lipids polarity (alkanes fits in
26
A. Shrivastava et al.
possible. For instance, grinding or simple pressing with algal paste or a diluted
algal suspension with water content higher than 60% cannot be used proficiently. In
contrast to other processes ultrasonic can be applied to wet biomass more effectively.
The process of cell destruction is accompanied by extraction of the lipids. Most
extensively used solvents include chloroform along with methanol. Other extraction
solvents include acetone, ethanol, acetone, and iso-propyl alcohol showing various
choices of efficiencies in extraction of lipid.
1.4.2 High-Pressure Homogenization
Charles Stacy French invented high-pressure homogenization. In this process of cell
disruption, the feed is passed through a very tiny orifice under high pressure which
results in hydraulic force creation and results in cell disruption. HPH was widely
used in extraction and sterilization of the inner constituents of micro-organisms.
Numerous benefits include formation of little heat, risk of thermal degradation is also
lower, lower reactor cooling rate, dead volume is almost nil, and simple scale up.
1.5 Extraction of Lipid
It is a critical step to the use of algae to produce fuels. It is probably an affordable
choice too. For release of the preferred products the algae cells must be subjected to
cell disruption. Methods include: 1) mechanical methods such as bead beating, 2)
electric field application, 3) application of sonic waves, 4) shock through osmosis,
and 5) expelling through manual press. Biological and chemical methods include: 1)
solvent extraction (single solvent, co-solvent, and direct reaction by transesterification), 2) supercritical fluids, and 3) enzymatic extraction.
1.5.1 Single Solvent Extraction
Among the commonest extraction techniques is the single extraction of solvents. A
lipid-like solvent, for instance, hexane, petroleum ether, or other solvent (which is
merely a light solvent and petroleum based in nature) is used. This method is
commercial. Extraction proceeds at high temperatures and with high pressure. The
benefits include an increased rate of mass transmission and solvent availability, and a
decreased immiscible solvent dielectric constant. A co-solvent method is a little
different to use. A solvent is chosen on two parameters. Option should include: 1) a
co-solvent polar in nature that disturbs the algal membrane cells, and 2) a co-solvent
with lesser polarity to better suit the extracted lipids polarity (alkanes fits in
26
A. Shrivastava et al.