Environmental Engineering Reference
In-Depth Information
8.3
Food Source from Red
Seaweeds
seaweed masala; Gracilaria edulis as seaweed
pickle, seaweed wafer, and seaweed jelly; and
Ulva lactuca as seaweed jam (Chennubhotla
et al. 1981 ).
Acanthophora or spiny sea plant, Asparagopsis
or supreme limu, Callophyllis or large wire weed,
Hypnea or maidenhair, Halymenia or red sea
lettuce, Laurencia or fl ower limu, and Scinaia
or tender golden weed are eaten fresh or raw;
chopped and cooked, especially with coconut
milk, or sprinkled as a spice in salads; used to
make pudding and jellies; and dried and rehydrated
in the Pacifi c regions (Novaczek 2001 ).
Gracilaria or sea moss is being used as
homemade agar, garnish for sashimi, used for
commercial agar, or fresh as a salad (Madlener
1977 ; Novaczek 2001 ). Gelidiella or little wire
weed is eaten after being simmered as a jelly in
Japan and Vietnam (Madlener 1977 ; Novaczek
2001 ; Tanaka and Nakamura 2004 ). Rhodymenia
palmata or dulse is the most common of edible
seaweeds in Europe and North America. Alaria
fi stula , Chordaria fl agelliformis , and Porphyra
umbilicalis are also used as food, while Porphyra
or purple lever is being consumed fresh or dried
in Japan, China, Korea, Vietnam, North America,
and Europe (Madlener 1977 ; Tanaka and
Nakamura 2004 ; Tsutsui et al. 2005 ). Eucheuma
and Kappaphycus or thorn grass, elkhorn
( Eucheuma ), and brown licorice algae tambalang
( Kappaphycus ) are being eaten with coconut
milk and sugar in Indonesia and Vietnam (Tsutsui
et al. 2005 ).
8.5
Production of Vegetable Oils
from Microalgae
Most current research on oil extraction is focused
on microalgae to produce biodiesel from algal
oil. The biodiesel from algal oil in itself is not
signifi cantly different from biodiesel produced
from vegetable oils. Dilution, microemulsifi ca-
tion, pyrolysis, and transesterifi cation are the
four techniques applied to solve the problems
encountered with high fuel viscosity. Of the four
techniques, transesterifi cation of oil into its cor-
responding fatty ester (biodiesel) is the most
promising solution to the high viscosity problem.
This is accomplished by mixing methanol with
sodium hydroxide to make sodium methoxide.
This liquid is then mixed into vegetable oil. The
entire mixture then settles and glycerin is left on
the bottom while methyl esters, or biodiesel, is
left on top. Biodiesel can be washed with soap
and glycerin using a centrifuge and then fi ltered.
Kinematic viscosities of the fatty acid methyl
esters vary from 3.23 to 5.61 mm/s (Knothe
2005 ). Methanol is preferred for transesterifi cation
because it is less expensive than ethanol (Graboski
and McCormick 1998 ). For production of
biodiesel, macroalga ( Cladophora fracta ) and
microalga ( Chlorella protothecoides ) samples
were used (Demirbas 2008 ). The higher heating
value of Chlorella protothecoides (25.1 MJ/kg) is
also higher than that of Cladophora fracta
(21.1 MJ/kg). Most vegetable oils are unsaturated.
The properties of the various individual fatty
esters that comprise biodiesel determine the
overall fuel properties of the biodiesel fuel. The
average polyunsaturated fatty acids of Chlorella
protothecoides (62.8 %) are also higher than
those of Cladophora fracta (50.9 %). Algae
generally produce a lot of polyunsaturates, which
may present a stability problem since higher
levels of polyunsaturated fatty acids tend to
decrease the stability of biodiesel. However,
8.4
Seaweed Recipes
It is known that about 100,000 tones of seaweeds
are eaten annually in Japan in the name nori, kombu,
and hakama. Seaweeds are rich in proteins,
vitamins, amino acids, growth hormones, miner-
als, and other trace elements. Hypothyroidism
(goiter) can be controlled by the intake of iodine-
rich seaweeds like Asparagopsis taxiformis ,
Sarconema spp., etc. Indian seaweed can be best
consumed as follows: Caulerpa sertularioides ,
Codium , Gracilaria confervoides , Hydroclathrus
clathratus , Laurencia papillosa , and Hypnea
valentiae as seaweed salad; Ulva lactuca as
Search WWH ::




Custom Search