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specific cultivation conditions, algal oil content can exceed 50% by weight
of dry biomass (Chisti, 2007).

6.6.2 Carbon Sequestration for Microalgae Growth
Microalgae have the capability to grow in nutrient-rich environments and
accumulate nutrients and metals from wastewater (de-Bashan and Bashan,
2010; Devi et al., 2012; Hoffmann, 1998; Mallick, 2002) employing hetero-
trophic cultivation. Microalgae cultivation with wastewater treatment is a
potential option for environmental sustainability and carbon neutrality. Five
characteristically different ecological water bodies (mixotrophic) were eval-
uated to assess the biodiesel production capability of their native microalgae
(mixed) (Venkata Mohan et al., 2014). The lipid yield varied between 4%
and 26%, which depends mostly on the nature and function of the water
body. Carpet mill effluent as feedstock showed its potential for algal biomass
growth associated with biodiesel production (Chinnasamy et al., 2010).
Cultivation of Scenedesmus sp. in fermented swine wastewater yielded lipids
and other value-added products in association with nutrient removal (Kim
et al., 2007). Nitrogen and phosphorus assimilation associated with lipid
production was studied with freshwater microalgae using industrial waste-
water (Li et al., 2012a,b). The functional role of macro/micro nutrients,
such as carbon, nitrogen, phosphorus, and potassium, in the heterotrophic
cultivation of microalgae (mixed) in domestic wastewater was studied on
biomass growth and lipid productivity employing sequential GP and SP
(Devi et al., 2012). Nutrient limitation during the SP showed a positive
influence on the lipid productivity. Nitrogen limitation can also activate dia-
cylglycerol acyl transferase, which converts acyl CoA to TAG (Takagi et al.,
2000). Acid-rich effluents from fermentative H 2 producing reactors were
evaluated as potential substrate for lipid accumulation by hetrotrophic
microalgae cultivation with simultaneous treatment (Venkata Mohan and
Devi, 2012). Microalgae can grow heterotrophically by utilizing VFA and
results in lipid accumulation. Acetate can be easily assimilated by the algal
cell as a part of the acetyl CoA metabolism in a single-step reaction catalyzed
by acetyl CoA synthetase (Boyle and Morgan, 2009). For achieving highly
dense microalgal cultures in mixotrophic mode, glucose along with in-
organic CO 2 can be utilized. Different concentrations of glucose as organic
carbon source was optimized for biomass growth and lipid accumulation
(Chandra et al., 2014).
Microalgae are considered to be photosynthetically more efficient than
terrestrial plants to fix CO 2 (Chiu et al., 2008; Indra et al., 2010). Algae can