Page 307 - Advances in Eco-Fuels for a Sustainable Environment

264 Advances in Eco-Fuels for a Sustainable Environment

Rice bran

Non catalytic
in situ trans(esterification)

Upper layer
Solvent extraction Vacuum evaporator

Water phase Filtrate
containing
fermentable Vacuum filtration Crude biodiesel
sugars Solid

Defatted rice bran Extraction of
unreacted oils and
bioactive compounds
using deep eutectic
Carbohydrate
solvent (DES)
Purified
biodiesel
Protein
Recovery of bioactive
Phenolic and compounds (γ-oryzanol)
flavonoid compounds

Fiber, etc. Bioactive compounds
(γ-oryzanol)

Fig. 9.3 The flow diagrams of value-added products (biodiesel and γ-oryzanol) produced from
rice bran.

compounds (g-oryzanol) from the DES phase will be easier because γ-oryzanol was
enriched in this phase. Consequently, by using the biorefinery concept as shown in
Fig. 9.3, the production cost of biodiesel can be lowered.

9.4.2 Biorefinery approach in biodiesel production from
microalgae
Microalgae have been touted as a potential feedstock not only in biofuel production
but also as a source of bioactive compounds. Even though the lipid content in the
microalgae cell is quite high, only using the microalgae lipid to produce biodiesel
is still not economically feasible. Valuable product generation from other constituents
of the microalgae cell could be a possible way to increase the profit of the product
output [27]. Although the composition of the cell depends on the microalgae species
and the cultivation conditions, many valuable products can be obtained from cells.
Constituents of microalgae can be divided into major components and minor compo-
nents. The major components are lipids, proteins, and carbohydrates while the minor