Microalgae: A Renewable Source of Bioproducts - Food and Industrial Bioproducts and Bioprocessing - page 229

-carotene isolated from the halotolerant
green alga Dunaliella salina grown in 400 hectare hypersaline 'lakes' at Hutt lagoon in
Western Australia and at Whyalla in South Australia.. At Whyalla, the company processes
up to one million litres of brine per hour. This pigment has a multitude of uses in food
products and as a source of pigmentation in farmed prawns (Borowitzka, 1999). Cognis
promotes its product Betatene ® as GRAS (Generally Recognized As Safe) for use as a
nutrient for food and beverage applications and as a natural colorant in water dispersible
powders and oils. Betatene ® actually contains a mixture of carotenoids, including
β

Cognis Australia is now a major supplier of β

-carotene, lutein, zeaxanthin and cryptoxanthin. It also contains both the cis
and trans isomers of

-carotene, α

β -carotene, compared to synthetic β -carotene which is almost entirely

the trans isomer.
Commercial production of carotenoids from microalgae is diversifying, with recent
interest in the fast-growing Chlorella protothecoides (chlorophyte) as a promising organism
for commercial production of lutein by heterotrophic fermentation (Shi et al ., 2002 ). Wei
et al . (2008) showed that the addition of reactive oxygen species (ROS) could increase
yields of carotenoid up to 31.4 mg/l with biomass yields up to 15.9 g/l.
While there is an already established market for some of the microalgal carotenoids, such

as -carotene, there is potential for other pigments in new applications or as an alternative

source for established applications. Fucoxanthin is receiving interest for a possible role in
combating obesity. While there are macroalgal sources (Miyashita et al ., 2011 ), microalgae
offer an attractive alternative with potentially novel applications, with early research
demonstrating interesting anti-proliferative activity of well differentiated pathologic cells
(Moreau et al ., 2006). Lutein, a carotenoid pigment from green algae, is receiving much
attention for prevention of age-related macular degeneration of the eyes. Research has
focused on screening for microalgae that produce high contents of lutein as well as
identifying conditions that optimise lutein production (Shi et al ., 2002 ; Del Campo et al .,
2007). Different procedures for recovery of the lutein from microalgal biomass are also
being investigated (Cer

β

ό n et al ., 2008 ).

9.9 PHARMACEUTICALS

Despite interest in microalgae as a source of pharmaceuticals since the 1990s, a commercial
product has yet to be achieved. Borowitzka (1995) reviewed efforts to screen for
antimicrobials, including antivirals, toxins and other pharmacologically active compounds,
as well as the hurdles that are needed to get a new pharmaceutical into the market place.
Microalgal toxins that are so significant in environmental issues, aquaculture and human
health when produced by harmful algal blooms (HABs) (Hallegraeff, 2003) have a role as
toxin standards. As part of biodiscovery for anticancer compounds, the US National Cancer
Institute played a major role in the search for bioactive compounds from algae having
anticancer properties (Apt and Behrens, 1999). Interestingly, there have been more drugs
leads from the cyanobacteria than eukaryotic microalgae, but Gerwick and co-workers
(1994) suggest that microalgae deserve more attention. The Natural Products Reports (e.g.
Pietra, 1997; Faulkner, 2002) give on-going information on the secondary metabolites of
microalgae and other microorganisms and their activity. Overall, the potential of microalgae
for pharmaceuticals remains largely untapped.