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Bioconversion of marine waste biomass for biofuel and value-added products recovery 487

medium-sized with colors of red, green, brown, and black (Brennan and Owende,
2010). Based on the pigments, seaweeds are classified into various types according
to their cell structure:
1. green algae (sea grapes and sea lettuce);
2. brown algae (kelp, kombu, arame);
3. red algae (laver, dulse); and
4. blue-green algae (chlorella, spirulina).

22.2.4.1 Rhodophyta

The world’s largest part of the seaweeds group comes under rhodophyta and is gen-
erally identified as red algae. The color of this seaweed is pure red or purplish
because of the presence of pigments called phycobilins. This is the distinctive char-
acter of red algae and the cyanobacteria. The common characteristics of red algae
are lack of flagella and centrioles, storage of starch in the cytoplasm, presence of
pigments such as phycoerythrin, phycocyanin, and allophycocyanin, and lack of
chloroplast endoplasmic reticulum (Elshahed, 2010).

22.2.4.2 Phaeophyta (brown algae)
Phaeophyta otherwise called brown algae are generally marine algae. Fucoxanthin
is the main pigment present in the phaeophyta, and this pigment is responsible for
brown color.
Branched, filamentous structure of brown algae with the presence of two layer
cell wall and inner layer having the cellulose and the outer wall is made up of algin
and fucoidan. These seaweeds are the essential resource of the industrial hydrocol-
loid alginate. The majority of brown algae are lithophytes, which require rigid sub-
strata for attachment (Tsui et al., 2006).

22.2.4.3 Charophyta
Charophyta is a collection of green algae mainly found in freshwater. Embryophyta
comes under terrestrial plants and appear inside the Charophyta. This green algae
living mainly in freshwater and having chlorophyll pigment a and b, cell wall con-
sist of cellulose, absence of phycobilins, and the starch has been stored within the
plastids (Murphy et al., 2007).

22.2.4.4 Streptophyta
Streptophyta is one of the green algae and the embryophyte otherwise called land
plants originated from streptophyte green algae. It is also the freshwater algae col-
lection of scaly, single cellular flagellates to multifaceted, in which streptophyte
and embryophyte distribution, while left over green algae is categorized as chloro-
phyta (Park et al., 2006). The charales (stoneworts) are frequently called a sister of
land plants. In addition, a lot of and physiological characters (e.g., type of photores-
piration, phytochrome system) have been emerged from this type of algae.