Value-Added Products from Microalgae - Biotechnological Applications of Microalgae - page 154

Low harvesting costs could be one of the key concepts in establishing the eco-
nomic viability of the entire system. However, these applications remain in their
infancy, and extensive research and development are needed. Successful technolo-
gies and processes are available for wastewater treatment, such as the Advanced
Integrated Wastewater Pond Systems (AIWPS) Technology, commercialized by
Oswald and Green in the United States (Olguín, 2003). Phycoremediation with the
employment of microalgae is a field with great promise and demand with so many
regions in the world prone to eutrophication.
10.3 CONCLUSION
Since the use of microalgae to survive the famine in China some 2,000 years ago,
the commercial applications of microalgae have been increasing rapidly. Of the
many microalgal species that exist, a few species are stored in collections, and only
a handful have been exploited for high-value products (Olaizola, 2003); hence, there
are only a few high-value products in the marketplace (Milledge, 2011). The chal-
lenge in progressing to commercialization can be overcome by focusing efforts on
products with a huge market potential and a distinct competitive advantage in large
markets such as food.
Algal biomass “health food” appears to be the main commercial product, fol-
lowed by food additives in the form of carotenes, pigments, and fatty acids. Algal
production within the health-food market has the highest sales value but is largely
dependent on health benefits and proof of efficacy (Becker, 2007; Milledge, 2011).
As natural additives, these commodities are superior to synthetic products, although
there is much to consider regarding the economics, sustainability, and environmental
perspectives of the production of each product (Harun et al, 2010; Milledge, 2011).
There are various factors to consider in developing manufacturing processes of
high-value metabolites. These include ensuring that proper taxonomic treatment is
applied such that efficient screening of the microalgae can be conducted—not only
for the fastest growing species, but also for those organisms with desirable robust
characteristics and valuable products. A key starting point is to expand the inven-
tory of microalgal species represented in culture collections and cell banks (Pulz
and Gross, 2004; Sekar and Chandramohan, 2008). Production systems are also an
important factor to consider. The type of production system depends on the nature
and value of the end-product (Metting, 1996). Currently, outdoor open-pond systems
are the mainstream mode of microalgal cultivation (Spolaore et al., 2006). The most
successful genera cultivated in open-pond systems are Spirulina, Dunaliella, and
Chlorella . Microalgal products of high value and purity, such as isotopically labeled
research compounds and reagent-grade phycobilins, are produced in photobioreac-
tor systems (Metting, 1993; Millledge, 2011). Overall operating and maintenance
costs of open-pond systems are lower compared to those of photobioreactors (which
are restricted mainly to the production of high-value products). Ideally, open ponds
make for a competitive cultivation alternative (Harun et al., 2010) and are likely to
be the way for commercial cultivation of microalgae. The location of the pond, algal
strain, light and CO 2 availability, final product yield, and quality are important fac-
tors to consider in open-pond cultivation systems.