Value-Added Products from Microalgae - Biotechnological Applications of Microalgae - page 138

applications is still emerging, but there have already been new areas of research in
microalgal biotechnology to satisfy the new product demands of industry and consumers.
The use of microalgae as food for human consumption is an age-old tradition.
Over 2,000 years ago, the Chinese used Nostoc to survive famine (Milledge, 2011).
Species such as Arthrospira ( Spirulina ) and Aphanizomenon have also been utilized
for decades as a source of food (Spolaore et al., 2006). Despite the plethora of historical
usage by humans, microalgal culture is a fairly new area of biotechnology research, and
its commercial application is virtually untapped (Spolaore et al., 2006; Milledge, 2011).
The interest in algal biomass came about in the 1950s as a result of an increase
in the world's population, and a forecast of insufficient protein supply triggered
the search for alternative novel protein sources (Spolaore et al., 2006). Today, the use
of algae for food still continues in many parts of the world; however, the large-scale
production of algae to eradicate the food calorie and protein shortage has not fully
materialized (Milledge, 2011).
There are a limited number of revolutionary companies that have persevered to
large-scale production of algal biomass and products. The algal products are nor-
mally marketed by the dominant players in the food and pharmaceutical industries.
However, there is a significant gap in the microalgal market for expansion of existing
products and the introduction of new products (Luiten et al., 2003; Pulz and Gross,
2004; Becker, 2007).
10.2 COMMERCIALLY EXPLOITED MICROALGAE,
PRODUCTS, AND APPLICATIONS
At present, the most significant product of microalgal biotechnology in terms of produc-
tion amounts and economic value is microalgal biomass (Figure 10.1; see color insert).
Microalgal biomass has been widely used in the fuel and energy sectors; however,
the nutritional value of algal biomass has endorsed its use as a high-protein supplement
in human nutrition, aquaculture, and as a nutraceutical (Del Campo et al., 2007).
The algal biomass market size is estimated at around 10,000 tonnes y −1 (dr y
weight) (Becker, 2007), with an annual turnover of over US$1.25 million (Milledge,
2011). Despite being a biodiverse resource, microalgae remain understudied in terms
of their morphology and physiology. Much of the literature regarding the systematics
and taxonomy of microalgae focuses on biotechnologically relevant species. More
than 200,000 species are known to exist; however, only 10 to 20 species (Table 10.1)
have been exploited worldwide for biomass, pigments, antioxidants, and special
products (toxins and isotopes) for various product applications (Borowitzka, 1992;
Radmer, 1996; Olaizola, 2003).
This chapter addresses in detail various types of high-value products derived from
algal biomass, their respective applications, production systems, and market positions.
10.2.1 C arotenoids
Carotenoids are colored, lipid-soluble compounds that occur in higher plants, micro-
algae, as well as in nonphotosynthetic organisms (Del Campo, 2007; Takaichi, 2011).
Carotenoids contribute to light harvesting, maintenance of structure, and functioning