Strain Selection for Biodiesel Production - Biotechnological Applications of Microalgae - page 21

Hyper lipid
Candidate
strain

Treatment of
single cell

Screening for
lipid

Aquatic sample

Prescreen: Nile red &
Epifluorescence
microscopy

Purification

Strain identification

Screening: High-
throughput methods

Disruption & further
separation

Storage

Qualitative and
quantitative analyses of
lipids

Concentration/
Enrichment

Isolation: Traditional/
automated

FIGURE 3.1 Schematic outline of procedures in bioprospecting algae for biodiesel
production.

of adaptation to the local climate and biota, meaning less energy expended on methods
of environmental control and sterile techniques. Specific criteria for the production of
biofuels from indigenous algae should include biomass and lipid productivity, harvesting
the cells, and oil extractability. Further, the algal oil derived should contain 20%-25%
C16 and C18 saturated fatty acid methyl esters and high amounts of unsaturated fatty
acid chains, thus offering more cleavage sites to produce hydrocarbons (Gunstone and
Harwood, 2007). Phycoprospecting may improve the efficiency of lipid extraction by
yielding organisms with traits amenable to oil recovery. For specific objectives such
as algal biodiesel, feedstocks for wastewater utilization or mitigation of greenhouse
gases (GHGs), the chosen algal strains should satisfy requirements such as the ability
to survive in wastewater, capability to grow robustly with higher cell densities, hyper-
lipid content as triacylglycerol, and be capable of heterotrophic or mixotrophic growth
as wastewater provides both organic and inorganic carbon sources. Until now, research
on screening and acclimation of microalgae to adapt to wastewater environments is
very sporadic (Zhou et al., 2011). A schematic outline and procedures in bioprospecting
algae for biofuel production are outlined in Figure 3.1.

3.2 ISOLATION AND CHARACTERIZATION OF
NATURALLY OCCURRING ALGAE
Despite the existence of morphologically diverse algae in a wide variety of terres-
trial and aquatic habitats, work with algae has been restricted to a relatively few
representatives. This seems partly the result of difficulties encountered in both